From 2 to 19

​➤ Anatomy of Oral Cavity, Palate & tongue

➤ Anatomy of Pharynx

➤ Anatomy of Salivary Glands

From 20 to 30

➤ Anatomy of anterior abdominal wall

➤ Anatomy of posterior abdominal wall

From 31 to 41
➤ Division of abdominal cavity

➤ Anatomy of Peritoneum

➤ Anatomy of Oesophagus

➤ Anatomy of Stomach

From 42 to 58
 ➤ Anatomy of duodenum

➤ Anatomy of Pancreas, spleen

➤ Anatomy of Rectum & anal canal, Ischiorectal fossa

From 59 to 66

➤ Anatomy of Liver & biliary system

From 67 to 77

➤ Arterial blood supply of GIT

➤ Portal circulation

➤ Splanchnic circulation
2023-2024

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Anatomy of the oral cavity

The oral cavity is separated into two regions by upper and

lower dental arches consisting of the teeth and alveolar bone
that supports them:
a) The outer oral vestibule, which is horseshoe shaped, is
between the dental arches and the deep surfaces of the
cheeks and lips. It opens into exterior by the oral fissure.
b) Oral cavity proper: the space enclosed by the dental
arches. Posteriorly it opens into the oropharynx by the
oropharyngeal isthmus, which is bounded:
 superiorly by the soft palate.
 inferiorly by the tongue Sublingual region seen when tongue is
turned upwards
 on each side by the palatoglossal arches.
The approximation of these arches shuts off the mouth
from oropharynx and is essential to deglutition
When the jaws are closed, the two parts of the mouth
cavity are connected by the space behind the last molar
tooth.
The floor of the mouth presents the following features:
1. Lingual frenulum (frenulum lingula): a median fold
of mucus membrane which connects the lower surface
of the tongue with the floor of the mouth.
2. Plica fimbriate: fold of mucus membrane on the sides
of the frenulum.
3. The sublingual fold: a small ridge on each side of the
lingual frenulum. It is formed by the underlying
sublingual gland, and it receives the openings of its
ducts.
4. The sublingual papilla: a small conical elevation on the anteromedial end of the
sublingual fold. The submandibular duct opens on its top.

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The Lips: two folds of skin and subcutaneous tissue surround the oral fissure and join
each other at the angles of the mouth. Each lip has a fold of mucus membrane called
labial frenulum connect it with the gum in the median plane. The outer surface of
upper lip has a depression in median plane called philtrum.
The cheeks: The cheeks lie on the sides of the oral fissure. They are covered externally
by skin and lined internally by mucus membrane.
Gums (Gingiva): These are highly vascular folds of dense fibrous tissue fixing the
teeth in the alveolar arches of the jaws.
The Teeth: They are either primary (deciduous) or permanent teeth.
A- Primary teeth:
 These teeth are temporary, and they erupt during the 1st two years after birth. They
are 20 in number, 10 in each jaw.
 They are arranged as 2 incisors, 1 canine & 2 molars in each half of jaw (Rt. or Lt.).
B- Permanent teeth:
They begin to replace deciduous teeth at the age of 6 y. They are 32 in number, 16 in
each jaw. They are arranged as 2 incisors, 1 canine, 2 premolars and 3 molars (in each
half of the jaw).

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It forms the roof of the mouth cavity separating it from nasal cavity and is formed of
hard & soft palate.
- Hard palate: It is formed from Rt. & Lt. halves separated from each other by inter-
palatal suture. Each half is formed from two parts:
1- Anteriorly: the palatine process of maxilla. It forms about the anterior ¾ .
2- Posteriorly: the horizontal plate of palatine bone. It forms the posterior ¼ .
The 2 parts are separated from each other by
palatomaxillary suture.
- Soft palate (called palatine aponeurosis):
 It is a mobile fold of fibrous tissues
covered by mucus membrane.
 It is attached anteriorly to the posterior
border of the hard palate.
 Its posterior border has a conical median
projection called the uvula.
 The soft palate swings up and down to
separate the nasopharynx from the
oropharynx (acts as a policeman) during
deglutition.
Muscles of the palate: These are 4 muscles (see
practical).
 Tensor palati  Palatopharyngeus
 Levator palati  palatoglossus
Nerve supply of the palate:
A. Motor: all muscles of the palate are supplied by the pharyngeal plexus except tensor
palati muscle which is supplied by a branch from mandibular n. (n. to
med.pterygoid).
B. Sensory: derived from the following nerves:
a. Greater and lesser palatine nerves and the naso-palatine nerve. These are
branches from maxillary nerve.
b. Branches from the glossopharyngeal nerve.

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Blood supply of the palate:

A. Arterial:
a) Greater palatine a.: branch from the 3rd part of maxillary a.
b) Ascending palatine a.: branch from the facial a.
c) Twigs from the ascending pharyngeal a.
B. Venous drainage: the veins of palate drain into the pharyngeal venous plexus
which end by two pharyngeal veins in the internal jugular vein.
- Lymph drainage of palate: drains into the deep cervical lymph nodes.

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Anatomy of the Tongue

- It is a muscular organ concerned
with speech, taste sensations &
deglutition.
- It has an apex, base, and two
surfaces: dorsal (upper) and ventral
(lower).
1) The apex (tip): directed
forwards. It lies behind the
incisor teeth.
2) The base: directed backwards.
It is attached to the mandible by
genioglossus muscle & attached
to hyoid bone by hyoglossus
muscle.
3) The dorsal (upper) surface: directed upwards towards the palate. It is divided by
V- shaped sulcus called sulcus terminalis into two parts:
a. The anterior 2/3 (called the oral part): lies Infront of the sulcus terminalis in
the floor of the mouth.
b. The posterior 1/3 (called the pharyngeal part): lies behind the sulcus
terminalis in the anterior wall of the oro-pharynx.
The apex of sulcus terminalis is directed backwards, and it has a narrow pit called
foramen caecum which is the embryonic remnant of the thyroglossal duct. This
duct gives origin to thyroid gland in fetus.
4) The ventral surface: Its mucus membrane is smooth, and it is reflected from the
lower surface of the tongue into the floor of the mouth. It presents special features
described with the floor of mouth.
- Lingual papillae: These are folds of mucus membrane on the dorsum of the anterior
two thirds of the tongue. They increase the surface area of the mucus membrane which
comes in contact with the food. They are Vallate, Fungiform, and Foliate papillae.
- The lingual tonsil: These are collections of lymphoid follicles in the submucosa of the
dorsal surface of the posterior 1/3 of the tongue.

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Muscles of Tongue:
1. Intrinsic muscles: see practical
2. Extrinsic Muscles: see practical
Blood supply of the tongue:
1- Arterial Supply of the Tongue:
a- Lingual artery: carries the main arterial supply of tongue.
b- Tonsillar branch of facial a. supplies post. part of tongue.
c- Twigs from ascending pharyngeal artery: supply the posterior part of the tongue.
2- Venous Drainage of the Tongue:
The tongue is drained by 2 groups of veins that lies superficial and deep to the
hyoglossus muscle. They join at the posterior border of the hyoglossus to form the
common lingual veins that end either in the internal jugular v. or in common facial v.

Nerve supply of the tongue:

1- Motor: All muscles of tongue (intrinsic and extrinsic) are supplied by hypoglossal n.
except the palatoglossus muscle which is supplied by the pharyngeal plexus.
2- Sensory:
a. The ant. 2/3:
1. General sensations carried by the lingual nerve (branch of mandibular n.).
2. Taste sensations carried by chorda tympani which is a branch from facial n.
b. The post. 1/3: both general & taste sensations are carried by glossopharyngeal n.
c. Root of the tongue (posterior part): both general and taste sensations are carried by
the internal laryngeal nerve (branch of the vagus nerve).
Lymphatic drainage of the tongue:
a. Anterior 2/3:
1. The tip drains into the submental L.N.
2. The margins drain into the submandibular L.N. of its side.
3. The central part drains into the submandibular L.N. of both sides.
b. Posterior 1/3: drain into the deep cervical L.N. of both sides.

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A) arterial supply of tongue. B) Veins of the tongue

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Anatomy of Salivary glands

1-Submandibular salivary gland
The submandibular gland is one of the three pairs of salivary glands is situated partly
below and partly deep to the posterior half of the mandible weights about 10–20 g.
Parts: It consists of two parts: (a) a large superficial part and (b) a small deep part. They
are superficial and deep to mylohyoid muscle subsequently. The two parts are
continuous with each other around the post. border of mylohyoid muscle.
a. A-Superficial part: The superficial part presents two ends anterior and posterior
and three surfaces inferior, lateral, and medial. The anterior end extends up to the
anterior belly of the digastric muscle. The posterior end extends up to the
stylomandibular ligament, which separates the submandibular gland from the parotid
gland.

b. B- Deep Part: It’s situated on the lateral surface of the hyoglossus below the lingual
nerve and the submandibular ganglion and above the hypoglossal nerve. It is related
laterally to mylohyoid.

The submandibular and sublingual glands

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Relations: Relations: The three surfaces of the superficial part have important relations:
A- Superficial surface (inferior surface) from superficial to deep is covered by the
following structures:
1. Skin.
2. Superficial fascia containing platysma & cervical br. of facial n.
3. Deep fascia.
4. Facial vein.
5. Submandibular lymph node
B-Lateral surface is related to:
1. Submandibular fossa on the inner aspect of the body of mandible.
2. Med. pterygoid ms. (near its insertion).
3. Facial artery.

C-Medial surface is extensive and divided into three parts anterior, middle & posterior:
(a) Anterior part is related to: - Mylohyoid muscle.
(b) Middle part is related to: Hyoglossus & Styloglossus muscles
(c) Posterior part is related to: Styloglossus muscle.2- Stylohyoid ligament.
B- Deep Part: It’s situated on the lateral surface of the hyoglossus below the lingual
nerve and the submandibular ganglion and above the hypoglossal nerve and its vena
commitants. It is related laterally to mylohyoid.
The submandibular duct:
It is 5 cm long. It arises from the deep part of submandibular gland. It runs

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forwards between the hyoglossus and the mylohyoid muscles. Then it passes between
the genioglossus medially and the sublingual salivary gland (laterally) where it is hooked by
the lingual nerve. Finally it opens in the floor of the mouth on an elevation called the
sublingual papilla on the side of the frenulum of the tongue.

2-The Sublingual gland

This is smallest of the three pairs of large salivary glands. It lies in the floor of the mouth
between the mucus membrane and the mylohyoid muscle. It is almond shaped and rests
in the sublingual fossa of the mandible. It is separated from the base of the tongue by the
submandibular duct. It is mostly mucus in nature and weighs about 3–4 g. The gland
pours its secretion by a series of ducts, about 15 in number, into the oral cavity on the
sublingual fold, but a few of them open into submandibular duct.
Blood supply the submandibular and sublingual glands: The glands are supplied by
facial and lingual arteries and drained by common facial & lingual veins.
Nerve supply of the submandibular and sublingual glands:
1- Sensory: from the lingual nerve.
2- Sympathetic:
a. Submandibular gland: from the plexus around the facial artery
b. Sublingual gland: from the plexus around the lingual artery.
3- Parasympathetic:
Preganglionic parasympathetic fibers from the superior salivary nucleus (in the
pons) pass with the facial nerve then with its chorda tympani branch.
The chorda tympani join the lingual nerve in the infratemporal fossa. The
parasympathetic fibers relay in the submandibular ganglion. Postganglionic
fibers pass directly to supply the submandibular and sublingual salivary glands.
Submandibular ganglion
 It is a parasympathetic ganglion which lies in the submandibular region. It lies on the
superficial surface of hyoglossus muscle suspended from the lingual nerve.
 Roots: 1) Sensory: branch from lingual nerve.
2) Sympathetic: from the plexus around the lingual artery.
3) Parasympathetic: mentioned above (parasympathetic nerve supply of
submandibular and sublingual salivary glands).
Branches: supply the submandibular and sublingual salivary gland

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3-The Parotid gland

- It is the largest salivary gland in the body.
Site: It lies below the external acoustic meatus between the angle of mandible &
sternomastoid muscle.
Shape: roughly pyramidal in shape. It has:
a- 2 ends: upper and lower.
b- 3 borders: anterior, posterior & medial border.
c- 3 surfaces: superficial (lateral), anteromedial & postero-medial surfaces.
Surface anatomy of the parotid gland:
It is represented by the four points:
 Point A: at the tragus of the auricle.
 Point B: at the mid-point of the
anterior border of the mastoid
process.
 Point C: at the midpoint of the
mandibular notch.
 Point D: at a point on the anterior
border of sternomastoid muscle 2cm
below and behind the angle of the
mandible.

The borders of the gland are represented Surface anatomy of parotid gland and its duct.

by the following lines:

Upper end by a line concave upwards between points A and B. It fits into the
external acoustic meatus
Anterior by a line from point A downwards and forwards to point C then it
border curves downwards and backwards to point D
Posterior by a line on the ant. border of sternomastoid muscle between points
border B and D.
Surface represented by the middle third of a line drawn between 2 points:
anatomy of  The tragus.
parotid duct:  A point halfway between ala of nose & red margin of upper
lip.

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The capsule of the parotid gland: It has two capsules:

1. True (inner) capsule: formed by condensation of the connective tissue of the
gland.
2. False (outer) capsule: formed from the deep cervical fascia which is splitted into
two layers; one passes superficial and the second passes deep to the gland. The
deep layer is attached between the styloid process and the angle of the mandible to
form the stylomandibular ligament. This ligament separates the parotid from the
submandibular gland.
Clinically: when the parotid gland is inflamed as in mumps. It is enlarged. The patient
suffers from severe pain due to firm enclosure of the gland by false capsule (deep
cervical fascia).
Relations of the parotid gland (fig):

The parotid duct & its course:

The parotid duct is 2 inches (5 cm) long. It emerges from the anterior border of the gland
and passes forwards on the masseter muscle, finger breadth below the zygomatic arch.

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At the anterior border of the masseter, it curves inwards and pierces the following
structures:
1) Buccal pad of fat.
2) Buccopharyngeal fascia.
3) Buccinator muscle.
4) Mucus membrane of the mouth.

Finally, it opens into vestibule of the mouth opposite upper 2nd molar tooth.
- Before it opens in the mouth the parotid duct passes a short distance between the
buccinator muscle & mucus membrane of the mouth. This oblique passage forms a
valve like mechanism which prevents inflation of the duct system during violent
blowing.
- It can be felt in the living by rolling a finger at upper part of the anterior border of
masseter muscle during clenching of teeth.
Structures inside the parotid gland:
1- Facial n. & its branches are superficial
2- External carotid a. is deep
3- Retromandibular v. (posterior facial v.) lies in between
4- Auriculo-temporal n.
5- Deep parotid lymph nodes.
How these structures enter and leave parotid gland?
1- Facial n.: enters the gland through its postero-medial surface & divides inside it
into 5 terminal branches. These branches are.:
 Temporal Leaves the gland through its upper end
 Zygomatic leave the gland through its anterior border. One or more of these
 Buccal
branches may be double.
 Mandibular
 Cervical Leaves the gland through its lower end
2- External carotid artery enters the gland through its postero-medial surface and
divides inside it into its 2 terminal branches: superficial temporal a. & maxillary a.
 The superficial temporal artery leaves the gland through its upper end.
 The maxillary artery leaves the gland through its antero-medial surface.

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3- The retromandibular vein: formed inside the gland by union of:

a- Superficial temporal vein enters the gland through its upper end.
b- Maxillary vein: enters the gland through its anteromedial surface. Within the
gland, the retromandibular vein divides into anterior & posterior divisions which
leave the gland through its lower end.
4- Auriculo-temporal nerve enters the gland through its anteromedial surface and
leaves it through its upper end.

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The accessory parts of the parotid gland:

1- The anterior border of the gland extends forwards above the parotid duct superficial
to masseter muscle. This part may be separated from the main part of the gland to
form the accessory parotid gland.
2- The upper part of gland may extend behind temporomandibular joint to enter the
mandibular fossa. So, patient with mumps feels severe pain during mastication.
Blood supply of parotid gland: Arterial: receives branches from external carotid a.
& its terminal branches. Veins: drain into the retromandibular vein.
Lymph drainage: lymph vessels from the parotid gland drain into the parotid lymph
nodes which in turn drain into the upper deep cervical lymph nodes.
Nerve supply of the parotid gland:
1- Sensory: from the auriculo-temporal nerve.
2- Sympathetic: from the plexus around the external carotid artery.
3- Parasympathetic (Very important):

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a) Preganglionic parasympathetic fibres arise from the inferior salivary nucleus in the
medulla oblongata and pass with the glossopharyngeal nerve.
b) passes in the jugular foramen the glossopharyngeal nerve gives its tympanic branch
which enters the middle ear to supply its mucosa and gives the lesser petrosal nerve.
c) The lesser petrosal nerve leaves the middle ear cavity and passes through foramen
ovale. It enters the infra-temporal fossa to relay in the otic ganglion.
d) Postganglionic parasympathetic fibres arise from the otic ganglion and pass with the
auriculo-temporal nerve (branch from the posterior division of mandibular nerve) to
reach to and supply the parotid gland.
- Clinically:
- Tumor in the parotid gland may compress the facial nerve causing unilateral facial
paralysis.
- The terminal branches of facial nerve run horizontally in the parotid gland. So
surgical incisions must be done transverse to avoid injury of these branches.
- The parotid duct is relatively superficial. It may be damaged in face injuries.

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Anatomy of pharynx
- It is a musculo-membranous tube which acts as passage for air and food.
- It begins at the pharyngeal tubercle at base of the skull and ends at the level of C6
where it continues with the oesophagus. It is 3.5 cm wide at its beginning and 1.5 cm
at its end, so it is wider above than below.
- Divisions: as it descends it lies behind the nose, the mouth and the larynx and opens
into each of these three parts.
- It is formed from three parts:
1- Nasopharynx: lies behind the nose
2- Oropharynx: lies behind the mouth and opens into it by oropharyngeal isthmus.
3- Laryngo-pharynx lies behind the larynx and opens into it by the laryngeal inlet.
Anatomy of Oropharynx:
Extension: It lies behind the oral cavity and extends from the level of the soft palate down to the level
of the upper end of the epiglottis.
Communications:
Anteriorly, with the mouth cavity via the oropharyngeal isthmus.
Inferiorly, continues with the laryngopharynx
Features:
A. Anteriorly: (i) posterior 1/3 of the tongue containing lingual tonsil.
(ii) upper free end of epiglottis.
(iii) median and two lateral (Rt &Lt) gloss-epiglottic folds with epiglottic vallecula in between.
B. Posteriorly: body of C2 vertebra and upper part of the body of C3 vertebra.
 Laterally: palatine tonsils. one on either side. It is located into a triangular fossa (tonsillar
fossa) bounded anteriorly by palatoglossal arch and posteriorly by palatopharyngeal arch.
Palatine tonsils fig. 2, two masses of lymphoid tissue, one on either side. It reaches its normal
maximum size in early childhood. It gradually atrophies after puberty It is located into a triangular fossa
(tonsillar fossa). The fossa bounded by:

 Anteriorly by palatoglossal arch (runs downwards and forwards from palate to the lateral
margin of the tongue).
 Posteriorly by palatopharyngeal arch (runs downwards and backwards to the pharyngeal
wall where it fades out).

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 Superiorly: the soft palate.

 Inferiorly: the posterior third of the tongue.
 Laterally: An incomplete fibrous capsule surrounds its lateral surface. This layer allows the
surgeon to decorticate the tonsil from its bed during tonsillectomy. Paratonsillar (external
palatine) vein lies in this layer: Injury of this vein during the tonsillectomy leads to severe
bleeding.
Blood supply
1- Tonsillar and ascending palatine branches of facial artery.
2- Twigs from the ascending pharyngeal artery.
3- Twigs from the greater palatine artery (branch from the 3rd part of maxillary artery).
4- Twigs from the dorsalis lingual arteries.
Lymph drainage End in the upper deep cervical lymph nodes especially the juglo-digastric lymph
nodes.
Waldeyer’s Ring: Circum-pharyngeal ring of mucosa-associated lymphoid tissue that surrounds the
openings into the digestive and respiratory tracts. It is made up anteroinferior by the lingual tonsil,
laterally by the palatine tonsils, and poster superiorly by the pharyngeal tonsil

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Anatomy of Anterior abdominal wall

Superficial fascia: It is a layer of variable amount of fat. Below the level of the
umbilicus, it is divided into 2 layers, superficial fatty layer, and deep membranous layer.
- The deep membranous layer: called Scarpa’s fascia has the following characters:
1- firmly attached to fascia lata (deep fascia of thigh) along a line parallel to the
inguinal lig.
2- Continues with Colle’s fascia (membranous layer of perineal superficial fascia).
The linea alba (linea= line, alba= white or bloodless):
It is a fibrous cord in the median plane of the anterior abdominal wall. It extends from
the xiphoid process to the upper border of the symphysis pubis. It is formed by
interlacing of the aponeurosis of the 3 muscles of lateral abdominal wall. It is wider
above the umbilicus than below it.
The umbilicus: a fibrous structure situated slightly below the middle of the linea alba. It
is variable in position.
a- In children it is lower due to incomplete development of the pelvis.
b- In adults it lies at level of the highest point of iliac crest opposite the (L3/ L4
disc).
Layers of anterior abdominal wall:
1- Skin. 3- Muscles.
2- Superficial fascia: 4- Fascia transversalis.
a. Superficial fatty layer. 5- Extraperitoneal fatty tissue.
b. Deep membranous layer. 6- Parietal peritoneum.
Muscles of anterior abdominal wall
- These are divided into two groups:
A) Muscles of the anterolateral part of the anterior abdominal wall: (see practical)
1- External abdominal oblique. 3- Transverses abdominis.
2- Internal abdominal oblique.
B) Muscles of the medial part of the anterior abdominal wall: (see practical)
4- Rectus abdominis. 5- Pyramidalis.
The rectus sheath:
- It is an envelope which surrounds the rectus abdominis muscle.
- It is formed by the aponeurosis of the three muscles of the lateral abdominal wall.
- The sheath is divided by two lines into three parts.
o The first line lies at the level of the costal margin.

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o The second line lies midway between the umbilicus and the symphysis pubis.
- Structure of each part of the sheath:
1. First part: it lies above the line at level of the costal cartilage:
a- Anteriorly: aponeurosis of the external abdominal oblique.
b- Posteriorly: 5th, 6th, and 7th costal cartilages.
2. Second part: it lies between the two lines:
a- Anteriorly: aponeurosis of the external abdominal oblique and the anterior
lamellae of the aponeurosis of the internal abdominal oblique muscle.
b- Posteriorly: the posterior lamellae of the aponeurosis of the internal abdominal
oblique muscle, and the transverses abdominis muscle and the fascia transversalis.
3. Third part: it lies below the second line:
a- Anteriorly: the aponeurosis of the external abdominal, the internal abdominal and
the transverses abdominis.
b- Posteriorly: the posterior wall of the sheath is deficient and is formed by the fascia
transversalis only.
The posterior wall of the rectus sheath ends at the second line in a curved line
concave downwards called arcuate line.
- Contents of the rectus sheath:
1- Two muscles: Rectus abdominis and Pyramidalis.
2- Two vessels: Superior epigastric vessels and Inferior epigastric vessels.
3- Lower five intercostal and subcostal nerves and vessels.

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Rectus sheath at 3 levels: A, above costal margin; B, between costal margin & arcuate line; C,
below arcuate line (EO = external oblique, IO = internal oblique, TA = transversus abdominis)

Inguinal ligament: The aponeurosis of the external abdominal oblique between the
pubic tubercle and the anterior superior iliac spine (ASIS). It’s free (has no attachment)
and is folded upwards and backwards on itself to form the inguinal ligament.
 The lower aspect of the ligament is round.
 Its upper aspect presents a groove which forms the floor of inguinal canal.
 Lacunar Ligament: the deep fibres from the medial end of inguinal ligament curve
horizontally backward to the medial part of the pectin pubis forming lacunar ligament.
 It is triangular.
 Apex: attached to the pubic tubercle.
 Lateral edge: sharp and forms the medial boundary of the femoral canal.

 Reflected Part of Inguinal Ligament: The superficial fibres from the medial end of
the inguinal ligament expand upward and medially to form this ligament. It lies behind
the superficial inguinal ring and in front of the conjoint tendon.
- Mid-inguinal point: It is a point on the inguinal ligament midway between the
symphysis pubis and the ASIS. The femoral a. passes deep to this point.

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Mid- point of the inguinal ligament: It is a point on the inguinal ligament midway
between the pubic tubercle & ASIS. It lies ½ inch lateral to the mid-inguinal point.
Fascia transversalis:
- This is a layer of deep fascia which lines the deep surface of the transverses
abdominis muscle. It is separated from the parietal peritoneum by extra-peritoneal
fatty tissue.
Superficial inguinal ring:
 It is a  opening in the aponeurosis
of external abdominal oblique
muscle. It lies immediately above
& lateral to the pubic tubercle. It
has an apex, base & 2 crura; medial
& lateral.
 Apex: directed upwards &
laterally.
 Base: formed by pubic crest.
 Structures passing through ring:
1. The spermatic cord in males or
the round ligament of uterus in
females.
Superficial inguinal ring
2. The ilioinguinal nerve in both
sexes.
The deep inguinal ring: a rounded opening in the fascia transversalis lying half an inch
above the mid-inguinal point.
 It has very important relations:
1- The external iliac a. descends behind fascia transversalis. Just below the ring the
external iliac a. gives 2 branches:
a. Inferior epigastric a. ascends upwards and medially behind fascia transversalis to
enter the rectus sheath infront of the arcuate line. Just after its origin it gives a small
but important branch called cremasteric a. which re-enters the ring to continue into
inguinal canal.
b. Deep circumflex iliac a. ascends upwards & laterally up to anterior superior iliac
spine.

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Deep inguinal ring

The inguinal canal

Definition: Oblique intermuscular passage about 4 cm long lying above the medial ½ of
inguinal lig.
Extent and direction: extend from deep inguinal ring to
the superficial inguinal ring. It is directed downward,
forward, and medially. On the body surface, the canal
is marked by 2 parallel lines (1 cm apart and 4 cm
long) just above the medial ½ of inguinal lig.
The boundaries of the inguinal canal:
 Anterior wall: It is formed from superficial to deep
by:

(a) Skin (b) Superficial fascia in the whole extent.

(c) External oblique aponeurosis. (d) internal oblique muscle fibers, in lat. 1/3.

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 Posterior wall: It is formed from deep to superficial by:

(a) Fascia transversalis, in the whole extent
(b) Conjoint tendon, in medial 2/3
(c) Reflected part of the inguinal ligament, in medial most part.
 Roof: It is formed by the lower arched fibers of internal oblique and transversus
abdominis muscles.
 Floor: It is formed by: (a) Grooved upper surface of the inguinal ligament in the
whole extent (b) Abdominal surface of the lacunar ligament at the medial end.
Contents: In male: spermatic cord and ilioinguinal nerve. In female: round ligament of
the uterus and ilioinguinal nerve.
Mechanisms of the inguinal canal: The inguinal Roof &floor of inguinal canal.
canal is a site of potential weakness in the
lower part of the anterior abdominal wall and may provide herniation of abdominal
viscera. But normally it is prevented by strength & good tone of the muscles of
anterior abdominal wall by the following mechanisms:
1. Flap-valve Mechanism: The canal is oblique (deep and superficial inguinal rings do
not lie opposite to each other).
2. Guarding of the Inguinal Rings: The deep inguinal ring is guarded anteriorly by
the internal oblique muscle, and superficial inguinal ring is guarded posteriorly by
the conjoint tendon and reflected part of the inguinal ligament.
3. Shutter Mechanism: The internal oblique surrounds the canal in front, above, and
behind like a flexible mobile arch and thus forming its anterior wall, roof, and
posterior wall. Consequently, when it contracts, the roof is pulled and approximated
on the floor like a shutter.
4. Slit-valve Mechanism: The contraction of external oblique muscle approximates
the two crura medial and lateral of superficial inguinal ring like a slit valve. The
intercrural fibers also help in this act.

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5. Ball-valve Mechanism:
Contraction of cremaster
muscle pulls the testis up and
the superficial inguinal ring
is plugged by the spermatic
cord.
Inguinal triangle (Hasselbach’s
Triangle):
Boundaries:
 Medially: Rectus abdominis.
 Laterally: Inf.epigastric
vessels.
 Inferiorly: Inguinal lig.
Direct and indirect inguinal hernias

Inguinal Hernia
Definition: A protrusion of abdominal viscera (e.g., loops of intestine) into the inguinal
canal. Clinically it presents as a pear-shaped swelling above and medial to pubic tubercle,
above the inguinal ligament.
Types of inguinal hernias:
Indirect inguinal hernia Direct inguinal hernia
 common in children & young adults. It is common in elderly due to weak
inciden

 more often in males > females. abdominal muscles.

ce

 commoner > direct inguinal hernia

It occurs if the hernial sac enters the It occurs if the hernial sac enters the
inguinal canal through the deep inguinal canal directly by pushing the
Course

inguinal ring, lateral to the inferior posterior wall of the inguinal canal
epigastric artery. forward, medial to inferior epigastric
artery through the Hasselbach’s triangle.

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The indirect inguinal hernia may be It is of two types:

congenital or acquired a) Lateral direct inguinal hernia.
a) Congenital indirect inguinal b) Medial direct inguinal hernia.
hernia: It occurs due to patent
Types

processus vaginalis.
b) Acquired indirect inguinal
hernia: It occurs due to increased
intra-abdominal pressure as during
weightlifting.

Complications of hernia: 1. Pain. 2. Obstruction. 3. Bowel necrosis. 4. Perforation.

The inguinal hernia must be differentiated from the femoral hernia:

Inguinal hernia Femoral hernia
More common in males More common in females
Incidence
Occurs in young age in middle and old age
 Deep inguinal ring (in
Site of protrusion oblique hernia)
Through the femoral ring
of hernial sac  Through inguinal ▲ (in
direct hernia)
Descent of hernia Into inguinal canal Into femoral canal
Site of the hernial Lies above and medial to Lies below and lateral to the
sac pubic tubercle pubic tubercle

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Anatomy of Posterior Abdominal Wall

The posterior abdominal wall extends from the 12th rib above to the pelvic brim below. It
is strong and stable because it is constructed by bones, muscles, and fasciae. It supports
retroperitoneal organs, vessels, and nerves.
The posterior abdominal wall is constructed as follows:
1. Bony part: In the median plane, it is made up by lumbar vertebrae & intervertebral
discs. Laterally it is made up by iliac crest, iliac fossa, and inner surfaces of the12th
rib.
2. Muscular part: Above the iliac crest, from medial to lateral sides, it is made up of
psoas major, quadratus lumborum, and transversus abdominis muscles. Below the
iliac crest on either side of the lumbar vertebral column from medial to lateral sides, it
is made up of psoas major and iliacus muscles.

Muscles of the posterior abdominal wall: Three muscles psoas major, iliacus, and
quadratus lumborum, on each side of the vertebral column form most of the posterior
abdominal wall.

Origin and insertion of the psoas major, psoas minor, iliacus, and quadratus lumborum muscles.

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Psoas Major
Origin: The muscle arises from 14 fleshy slips that are as follows:
1. five slips from intervertebral discs between T12–L5 vertebrae and adjoining
margins of the bodies of these vertebrae.
2. Five slips from anterior surfaces & lower borders of transverse process of L1-5.
3. Four slips from tendinous arches bridging the constricted sides of the bodies of
lumbar vertebrae. The lumbar vessels pass deep to these arches.
Insertion: From the site of origin, the muscle descends along the pelvic brim and
enters the thigh behind the inguinal ligament and inserted into the anterior
surface of the tip of the lesser trochanter of the femur.
Nerve Supply: by direct branches from ventral rami of L2, L3, L4 spinal nerves.
Actions: These are as follows:
1. Acting from above, it is the chief flexor of the thigh at the hip joint.
2. Acting from below, it flexes the trunk on the thigh, as in raising the trunk from
recumbent to sitting position.
Psoas minor:
This muscle is present in about 50% individuals. When present, it runs downward in front
of psoas major.
Origin: It arises from the side of the intervertebral disc between T12 and L1 vertebrae
and adjoining parts of their bodies.
Insertion: From the site of origin, the muscle runs in front of the psoas major and ends
in a long flat tendon, which is inserted into the iliopubic eminence.
Nerve Supply: It is by a branch of L1 spinal nerve.
Action: It is a weak flexor of the trunk.
Iliacus
It is a fan-shaped muscle and forms the lateral component of the iliopsoas muscle.
Origin: It arises from the upper two thirds of the floor of iliac fossa, inner lip of iliac
crest and upper surface of the lateral part of the sacrum.
Insertion: The fibres converge on and fuse with the lower part of the psoas major
medially and inserted with it on the anterior surface of lesser trochanter of the
femur and an area (2.5 cm long) below it.
Nerve Supply: It is by the femoral nerve.
Actions: with psoas major, it causes flexion of thigh & lumbar part of vertebral column.

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Quadratus Lumborum
Origin: It arises from:
(a) Posterior one-third of the inner lip of the iliac crest and Iliolumbar ligament.
(b) Lower two to four transverse processes of lumbar vertebrae.
Insertion: The muscles run upward and medially pass posterior to the lateral arcuate
ligament to be inserted into the medial part of the anterior surface of the 12th rib. It
is also inserted into upper lumbar transverse processes, post. to its slips of origin.
Nerve Supply: It is by ventral rami of T12–L3/L4 lumbar spinal nerves.
Actions: These are as follows:
1. it is a lateral flexor of the lumbar vertebral column.
2. It fixes the 12th rib during inspiration for effective contraction of the diaphragm.
3. Muscles of both sides acting together extend the lumbar vertebral column.

Posterior abdominal wall muscles (real anatomy) Relation of iliacus & psoas major muscles to
inguinal lig.

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Abdominal cavity
The abdominal cavity is divided into nine regions by four imaginary planes (2 vertical &
2 horizontal) on ant. abdominal wall.

1. Superior horizontal plane

(transpyloric plane): It is placed midway
between the suprasternal notch and the
pubic symphysis. It lies at the level of
lower border of L1 vertebra and cuts costal
margin at 9th costal cartilages.

N.B. the subcostal plane is used in

preference to the transpyloric plane. This is
drawn through the lowest parts of the
costal margins at the 10th costal cartilages
and lies at the level of the body of L3
vertebra.

2. Inf. horizontal plane (intertubercular

plane): It is drawn at the level of tubercles
of the iliac crests. It lies at the level of upper border of L5 vertebra.

3. Rt. & Lt. vertical planes (midclavicular planes): from the midpoint of the clavicle to
the mid-inguinal point (a point midway between anterior superior iliac spine &
symphysis pubis).

Nine regions marked out are arranged into three horizontal zones of abdomen: upper,
middle, and lower. They are arranged from right to left
 In upper abdomen (Rt. hypochondrium, epigastric region & Lt.
hypochondrium).
Planes and regions of abdominal cavity.
 In the middle abdomen (Rt. lumbar
region, umbilical region & Lt. lumbar region).
 In the lower abdomen (right iliac fossa, hypogastric region, and left iliac fossa).

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Anatomy of Peritoneum
Definition: is a large thin serous membrane, which lines the interior of the
abdominopelvic cavity. It forms the largest serous sac of the body.

The invaginations by the organs have different forms:

- Some organs invaginate the peritoneum and develop a peritoneal fold connecting them
with the posterior abdominal wall. These organs become covered completely by
peritoneum except at the line of attachment to the peritoneal fold.
- Other organs invaginate the peritoneal sac to a lesser degree and become covered by
peritoneum on the front and sides only.
- Some other organs don’t invaginate the peritoneal sac and covered by the peritoneum
anteriorly only e.g., the duodenum.
Due to the invagination of the peritoneal sac by the organs and formation of peritoneal
folds and the ligaments the peritoneal sac is divided into two sacs; greater and lesser
sac, completely separated from each other except at an opening called epiploic
foramen (of Winslow) or opening into lesser sac.

- Layers of the peritoneal sac:

The peritoneum covering the organs is called visceral peritoneum, and that which
lines the abdominal wall is called parietal peritoneum. The 2 layers are separated from
each other by a potential space called the peritoneal sac which contains a film of
serous fluid called the peritoneal fluid. The peritoneum is a completely closed sac
except the opening of the uterine tube in female.

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- Folds of the peritoneum: These folds

stretch between the organs covered by
peritoneum and the abdominal wall or
other organs. They function to allow
free mobility of the included organs.
These folds have different names
according to the organ included as
omentum, ligament or mesocolon but
the structure is the same. As a role each
peritoneal ligament irrespective to its
name is formed from two layers except
the greater omentum as it is reflected Peritoneal folds.
on itself hence formed of 4 layers:
A- Peritoneal folds:
1. Omenta: Lesser & Greater
omentum.
B- Mesenteries:
1. Mesentery of small intestine.
2. Transverse mesocolon.
3. Pelvic (sigmoid) mesocolon.
C- Ligaments:
1. Falciform ligament.
2. Gastrosplenic ligament.
3. Gastrophrenic ligament.
4. Phrenicocolic ligament.
5. Lienorenal ligament.

Lesser omentum: stretched between the

lesser curvature of the stomach and the Subdivisions of Peritoneal Cavity.

margins of the porta hepatis of the liver. Its right border is free and forms the anterior
boundary of the opening into the lesser sac.

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Greater omentum: stretched between the greater curvature of the stomach and the
transverse colon. It is formed by the peritoneum covering the anterior and the posterior
surfaces of the stomach. The 2 layers descend in the abdominal cavity till the pelvis
acting as a rope to protect the abdominal organs then reflected backwards and upwards
forming posterior two layers up to the anterior border of the pancreas where they diverge.
The ant. one ascends on the ant. surface of pancreas & the post. passes on its inferior
surface.

Subdivisions of the peritoneal cavity:

- The peritoneal cavity is a completely closed sac subdivided in lesser and greater sacs,
which communicate together through the epiploic foramen.
- The lesser sac, or omental bursa, is situated behind the stomach & lesser omentum.

Contents of the right free border of lesser omentum:

 Portal v. (posteriorly).
 Hepatic a. (infront of portal v. and to the left of common bile duct).
 The common bile duct (infront of portal v. & to the right of hepatic a.).

Epiploic foramen (of Winslow) is a short, vertical slit in the upper part of the right
border of the lesser sac .
- It leads into the greater sac.
- It is 3 cm in height in adults.
- Boundaries:
 Anterior: The thickened right edge of the lesser omentum.
 Posterior: The peritoneum covering the I.V.C.
 Above: caudate lobe of liver.
 Below: 1st inch of 1st part of duodenum.

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- It is a muscular tube 25 cm long 2cm wide.

- Begin: at the level of C6 as a continuation of the pharynx.
- End: ends at the cardiac end of the stomach at level of T11 corresponding to xiphoid
process of sternum.
- It has a slight sinuous course but mostly lies in the midline. It starts in the midline
then inclines to the left as far as the root of the neck then gradually returns to the
midline then deviates to the left again to reach its opening in the diaphragm.

Parts of the oesophagus: it has 3 parts:

a- Cervical part (in the neck): the most upper part in lower part of the neck.
b- Thoracic part (in the thorax): it descends anterior to the vertebral column through
the sup. & Post. mediastina until reaching oesophageal opening of diaphragm (one
inch to the left of the median plane at the level of T10).
c- Abdominal part (in the abdomen): It is very short (1–2.5 cm in length) and ends in
the cardiac end of stomach. It lies behind the oesophageal groove of the lt. lobe of
liver.
Oesophageal constrictions (see practical):
1st constriction  at the beginning point. It is the 2nd narrowest point of alimentary
(upper tract (the narrowest is the vermiform appendix).
oesophageal  It is located 15 cm after maxillary central incisor teeth.
sphincter)  corresponds to body of 6th cervical vertebra
2 constriction  It is made by aortic arch & corresponds to T4.
nd

 It is located 22.5 cm after maxillary central incisor teeth.

3 constriction  located at crossing point of oesophagus &lt. main bronchium.
rd

 located at level of T5. It is 27.5 cm after maxillary central

incisor teeth
4 constriction  made by oesophageal opening in the right crus of diaphragm.
th

(lower  located at level of T11. It is 40 cm after maxillary incisor teeth

oesophageal  It is a physiological sphincter mechanism made by muscle fibers
sphincter) of right crus of diaphragm

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Blood supply:
1- Cervical part: the inferior thyroid artery & vein.
2- Thoracic part: from descending aorta and drains into azygos & hemiazygos veins.
3- Abdominal part: the left gastric artery & vein.
Lymphatic drainage: lymph vessels from the oesophagus drain into the following L.N:
1- Cervical part: paratracheal and the lower deep cervical lymph nodes.
2- Thoracic part: posterior mediastinal lymph nodes.
3- Abdominal part: left gastric lymph nodes

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Anatomy of stomach
- It is most dilated part of the gut.
- Shape: the stomach is J-shaped.
- It lies in the upper part of the left side
of the abdominal cavity in the
epigastrium, umbilical region & left
hypochondrium.
- It has:
1. Two openings; cardiac and
pyloric,
2. Two curvatures; lesser and greater
3. Two surfaces; anterior and
posterior. Boundaries of epiploic foramen and contents of the right
free border of lesser omentum.

Openings:
1- Cardiac opening: connects the stomach with oesophagus. It lies one inch to the left
of the median plane, at the level of the 11th thoracic vertebra, opposite the left 7th
costal cartilage, four inches deep to the anterior abdominal wall.
2- Pyloric opening: connects the stomach with the duodenum. It lies one inch to the
right of the median plane, at the level of L1 (transpyloric plane).
Curvatures:
1- Lesser curvature: begins at the right border of the cardiac orifice. It is concave to
the right side. Near its pyloric end, it has a notch called angular notch or incisura
angularis. It gives attachment to the lesser omentum. The right and left gastric
vessels run along it.
2- Greater curvature: begins at the left border of the cardiac orifice. At first it ascends
upwards, backwards and to the left to form the fundus of the stomach, then it
descends downwards forwards and to the right. It is convex to the left. Opposite
the angular notch of the lesser curvature, it presents a dilatation or bulge.
It gives attachment to three peritoneal ligaments:
a- The Gastrophrenic lig. attached to its upper part.
b- The gastrosplenic lig. attached to its middle part. The short gastric vessels run in
this ligament.

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c- The greater omentum attached to its lower part. The Lt. & Rt. gastroepiploic
vessels run in it.
Parts of the stomach:
- It is divided by two lines into four parts.
The first line is drawn horizontally from
the lower part of the left border of the
cardiac orifice to the greater curvature.
The second line is drawn from the
angular notch of the lesser curvature to
the beginning (left end) of the dilatation
on the greater curvature.
- The parts are:
1. Fundus: above the first line.
2. Body: the part between the two
lines.
3. Pylorus: the part distal to the second
line. It is subdivided into:
a. Pyloric antrum: the dilated left part Parts of the stomach
of the pylorus.
b. Pyloric canal: the narrow middle part.
c. Pyloric sphincter: the junction of the stomach with the duodenum. It is
characterized by presence of a constriction on its outer surface due to the
presence of circular muscle fibers. The wall is thick compared to that of the
stomach, other parts of the pylorus or the duodenum. Presence of the prepyloric
vein (vein of Mayo): a small but constant vein which runs infront of the pylorus
connecting the Rt. gastric v. with the Rt. gastroepiploic v.
Peritoneal covering and ligaments of the stomach:
 The stomach is completely covered by peritoneum except a small area on its posterior
surface near the cardiac orifice. This area called bare area of the stomach & related to
the Lt. crus of the diaphragm.
 The peritoneum covering the anterior and the posterior surfaces of the stomach meet at
the lesser curvature to form the lesser omentum. The two layers of peritoneum meet at
the greater curvature to form greater omentum, gastrophrenic & gastrosplenic
ligaments.

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Surfaces:
1- Anterior surface: It is directed antero-superiorly. It is related to:
a. Lt. lobe of liver infront of the fundus.
b. Anterior abdominal wall.
c. Diaphragm separating the stomach from the left 6th to the left 9th ribs.
d. Quadrate lobe of the liver related to the pylorus.
e. The anterior surface of the stomach is separated from these structures by the
cavity of the greater sac.

2- Posterior surface (stomach bed): directed posteroinferiorly and related to several

structures known as stomach bed. These structures from below upwards are:
a- Transverse colon and transverse mesocolon containing the middle colic vessels.
b- Splenic artery running in a tortuous course along its upper border.
c- Body of pancreas f- Left crus of the diaphragm.
d- Front of left kidney g- The spleen.
e- Left suprarenal gland.
The stomach is separated from these structures by the cavity of the lesser sac except the
spleen which is separated from the stomach by the cavity of the greater sac.

Stomach bed

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Surface anatomy of the stomach:

1. Cardiac orifice: represented by two vertical lines one cm each drawn at the level of
the 7th costal cartilage one inch below and to the left of the xiphi-sternal junction.
2. Pyloric orifice: represented by two horizontal lines one cm each drawn at the level of
the transpyloric plane one inch to the right of the median plane.
3. Lesser curvature: represented by a line concave to the right side from the lower end
of the right vertical line to upper horizontal line.
4. Greater curvature: represented by a line from the lower end of the left vertical line.
At first this line passes upwards, backwards and to the left to reach the left 5 th
intercostal space at the midclavicular line to define the fundus. Then this line passes
downwards, forwards and to the right to pass at the level of left 10 th costal cartilage.
Then it continues to join lower horizontal line. This line is convex downwards and to
the left.
Blood supply of the stomach:
- Arterial:
1. Lt. gastric a.: branch from celiac trunk.
2. Right gastric a.: branch from hepatic a.
Both Rt. & Lt. gastric arteries anastomose with each other on the lesser curvature.
3. Short gastric arteries: these are six branches from the splenic artery. They pass in the
gastrosplenic ligament to supply the fundus of the stomach.
4. Left gastroepiploic artery: branch from the splenic artery. It runs on the greater
curvature
5. Right gastroepiploic artery: branch from the gastroduodenal artery branch of hepatic
artery. It runs on the greater curvature of the stomach.
- Venous drainage: the veins of the stomach accompany its arteries and they end either
in the portal vein or one of its tributaries. These veins are:
1. Left and right gastric veins end in the portal vein.
2. Short gastric veins and the left gastroepiploic vein end in the splenic vein.
3. Right gastroepiploic vein ends in the superior mesenteric vein.
Nerve supply of the stomach:
a) Sympathetic: from the celiac plexus around the celiac trunk.
b) Parasympathetic: from both vagus nerves through the anterior & posterior gastric
nerves.

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Lymphatic drainage of the stomach: The lymph vessels of the stomach also accompany
its arteries and they end in one of these lymph nodes groups:
1. Paracardial. 2. Left gastric. 3. Pyloric. 4. Hepatic. 5. Right gastroduodenal. 6.
Pancreatico- splenic.
From these lymph nodes efferent vessels drain into the celiac group of lymph nodes

Blood supply of the stomach

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Anatomy of duodenum
Is the widest, and most fixed part of small
intestine.

Site: above the level of the umbilicus opposite

to the L1, L2, L3 vertebrae.

Shape: it is C-shaped. Its concavity is directed

upwards and to the left where it surrounds the
head of the pancreas. It is formed from 4 parts:
- 1st part: passes horizontally to the right side
at the level of transpyloric plane (L1).
- 2nd part: It descends vertically from the level
of (L1) to the level of (L3).
- 3rd part: passes horizontally from the Rt. to
Lt. at the level of subcostal plane (L3).
- 4th part: It passes upwards and to the left Parts of the duodenum.

from the level of L3 to end at level of L2 at

duodenojejunal flexure.
Peritoneal covering: It is retroperitoneal except
for its beginning, which is connected to the liver by the hepatoduodenal ligament, a
part of the lesser omentum.
Important relations:
a) The 1st part: extends from the pyloric orifice of the stomach to the neck of the
gallbladder and passes anteriorly to the bile duct, gastroduodenal artery, portal
vein, and IVC. Clinically, the beginning of this part of duodenum is referred to as

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the ampulla or duodenal cap & most duodenal ulcers occur in this part of
duodenum.
b) The 2nd part Its anterior surface is crossed by the transverse colon, posterior to it
is the right kidney, and medial to it is the head of pancreas.
 This part of the duodenum contains Posterior relation of 1st part of duodenum

the major duodenal papilla, where the common hepatopancreatic duct opens
on its summit, and the minor duodenal papilla above it, which receives
opening of the accessory pancreatic duct (for illustrating image see pancreas).
 The junction of the foregut & midgut occurs just below major duodenal papilla.
c) The 3rd part: is the longest section, crossing the inferior vena cava, the aorta, and
the vertebral column. It is crossed anteriorly by the superior mesenteric a. & v.
d) The 4th part: of the duodenum passes upward on (or to the left of), the aorta to
approximately the upper border of L2 and terminates at duodenojejunal flexure.
 This duodenojejunal flexure is surrounded by a fold of peritoneum containing
muscle fibers called the suspensory muscle (lig.) of duodenum (lig. of Treitz).

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Relations of the duodenum

Blood supply of the duodenum:

 Arterial:
1. Upper half of the duodenum till the middle of the 2nd part is supplied by branches of
the celiac trunk (artery of the foregut). These branches are:
- Supra duodenal artery.
- Right gastric artery
- Superior pancreaticoduodenal artery
2 Lower half of the duodenum distal to the middle of the 2 nd part is supplied by the
inf. pancreaticoduodenal a. which is a br. from sup. mesenteric a. (artery of the
midgut).
1- Venous drainage: the veins of the duodenum drain into the portal vein

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Anatomy of Pancreas
- It is a mixed endocrine and exocrine gland which is situated transversely across the
posterior abdominal wall from the concavity of the duodenum on the right side to the
spleen on the left side.
- Its length is 12 – 14 cm.
- The pancreas has head, neck, body, and tail.
A- Head: lies in the concavity of the duodenum. It has a projection from its lower left
part called the uncinate process. This process is directed upwards and to the left.
Relations:
1- Anteriorly: transverse colon. The uncinate process is related anteriorly to the
superior mesenteric vessels
2- Posteriorly: the I.V.C. and the terminal parts of the renal veins. The common
bile duct lies infront of the I.V.C. and is embedded in the posterior surface of
the head.
3- Above: first part of the duodenum.
4- Right side (laterally): the second part of the duodenum separated from it by the
superior and inferior pancreaticoduodenal vessels.
5- Below: the third part of the duodenum.
B- Neck of the pancreas: It is a constriction of about 2 cm in length. It lies in the
median plane at the level of the transpyloric plane (L1).
Relations:
Anteriorly: related to the first inch of first part of the duodenum separated from it
by the cavity of the lesser sac.
Posteriorly: related to the beginning of the portal vein by the union of the splenic &
superior mesenteric veins (very important anatomical & surgical landmark).

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Relations & parts of pancreas

C- Body: triangular in cross section. It has three borders: anterior, inferior, and
superior, and three surfaces, anterior, posterior, and inferior. Relations of the
surfaces:
1- Anterior: related to the posterior surface of the stomach separated from it by
the cavity of the lesser sac.
2- Posterior: It is related to the following structures from right to left:
1. Abdominal aorta and the origin of the superior mesenteric artery.
2. The splenic vein infront of the abdominal aorta and above the origin of the
superior mesenteric artery.
3. Left renal vein below the origin of the superior mesenteric artery and it
separates the superior mesenteric artery from the abdominal aorta.
4. Front of the lower part of the left suprarenal gland.
5. Front of the left kidney. 7. Left psoas major muscle.
6. Left sympathetic chain. 8. Left crus of the diaphragm.
3- Inferior: from right to left it is related to:
a- Duodenojejunal flexure. b- Loops of small intestine.
c- Left colic flexure.

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- Borders of the pancreas:

1- Superior border: It intervenes between the anterior and the posterior surfaces. At its
beginning it has an elevation called tuber omental or omental tuberosity of the
pancreas. This tubercle projects beyond the lesser curvature of stomach & comes in
relation to the celiac trunk & the lesser omentum hence the name omental
tuberosity.
The splenic artery runs in a tortuous course along the upper border of the pancreas.
2- Anterior border: It intervenes between the anterior and the inferior surfaces. It
gives attachment to the two layers of the transverse mesocolon which diverge; the
anterior of which passes on the anterior surface and the posterior layer passes on
the inferior surface of the pancreas.
3- Inferior border: It intervenes between the inferior and posterior surfaces of
pancreas.
D- Tail of the pancreas: It is a tapering part, and it passes in the lienorenal ligament
to the spleen where it is related to its visceral surface below and lateral to its hilum.
- Ducts of the pancreas:
1- Main pancreatic duct: It begins at the tail of the pancreas and passes to the right
side within the body till it reaches the neck. At the neck it inclines downwards and
to the right side within the head. It unites with the common bile duct to form the
common hepatopancreatic duct
(ampulla of Vater).
2- Accessory pancreatic duct: It
begins at the lower part of the
head near the uncinate process.
It ascends upwards and to the
right side passing infront of the
main pancreatic duct. It opens
in the posteromedial wall of the
second part of the duodenum
on the top of the minor
duodenal papilla situated 2 cm
above major duodenal papilla.
Ducts of pancreas.

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Peritoneal covering:
2- The body: its anterior and inferior surfaces are covered by peritoneum while its
posterior surface is devoid of peritoneal covering. So, the body of pancreas is fixed
to the post. abdominal wall.
3- The tail: is completely covered by peritoneum as it lies within the lienorenal lig.
- Blood supply of the pancreas:
A) Arterial:
1- Pancreatic branches of the splenic artery: these are 20 small arteries which arise
from splenic a. as it runs its tortuous course along the upper border of pancreas.
2- Superior pancreaticoduodenal artery: branch from the gastroduodenal artery
which is a branch from the hepatic artery.
3- Inferior pancreaticoduodenal artery: branch from the superior mesenteric artery.
B) Venous drainage: the veins of the pancreas drain into the splenic vein, and the
superior mesenteric vein. These veins finally drain into the portal vein.
- Lymphatic drainage: into pancreatico-splenic & pancreatico-duodenal lymph nodes.
- Surface anatomy of the pancreas: It is represented by three points and a small line:
1- Point A & point B are present where the transpyloric plane crosses the midline and
the left midclavicular line respectively.
2- Point C present at the crossing of the subcostal plane with the midline.
3- A small line is drawn 2 inches to the right of the median plane parallel to a line
between the points A and C.
a- The head lies in the interval between the line & a line between the points A &
C.
b- The body lies in the triangle between the three points, A, B and C.
c- The tail lies at the point B.

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Anatomy of the spleen

The spleen is the largest lymphoid organ in the body

Site: The spleen lies in the lt. hypochondrium between fundus of the stomach and
the diaphragm, behind the midaxillary line opposite the 9th, 10th, and 11th ribs. Its
long axis lies parallel to the long axis of the 10th rib.

Site of the spleen

Shape, and Colour: The spleen is a wedge-shaped soft organ with purple colour.
Size: it is usually 3–4 cm thick, 7 cm broad, and 12 cm long (1’’ x 3’’ x 5’’)
Weight :150-200 gm
External features: the spleen has:
1. Two ends: anterior and posterior.
a) The anterior end (lateral end/lower pole) is broad and is more like a border. It is
directed downward, forward, and to the left. It rests on the phrenico colic
ligament below.
b) The posterior end (medial end/upper pole) is rounded. It is directed upward,
backward, and medially towards the vertebral column.
2. Three borders: superior, inferior, and intermediate.

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a) Superior Border: it’s a thin and convex border. It characteristically presents

1-2 notches near its anterior end. These notches indicate that the spleen
develops by the fusion of separate masses of lymphoid tissue (lobulated
development). It ends laterally by an angle.
b) Inferior Border: a rounded, thick and smooth with no notches.
3. Two surfaces: diaphragmatic and visceral.
a) The diaphragmatic surface is smooth, convex, and related to the diaphragm
b) The Visceral surface: concave and irregular. It presents four impressions:
gastric, renal, colic, and pancreatic
 The gastric impression is produced by the fundus of the stomach. It is the
largest impression and lies above the hilum of spleen.
 The renal impression is produced by the left kidney and lies between the
hilum and the inferior border.
 The colic impression is produced by the left colic flexure. It is ▲ in shape
and situated close to the lateral end.
 The pancreatic impression is produced by the tail of the pancreas. It is
located between the hilum and the colic impression (below the lateral end
of the hilum).

Relations of the visceral surface & impressions

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Peritoneal covering: The spleen is completely enclosed in the peritoneum except at its
hilum, from where two peritoneal folds extend — one to the stomach and one to the left
kidney, called gastrosplenic and lienorenal ligaments, respectively
1. Gastro-splenic lig. extends from the hilum of the spleen to the upper one-third of the
greater curvature of the stomach. It contains short gastric vessels.
2. Lieno-renal lig. extends from the hilum of the spleen to the anterior surface of the left
kidney. It contains (a) tail of the pancreas, (b) splenic vessels, and (c) pancreatico
splenic lymph nodes.
3. Phrenico-colic lig.: It is a triangular fold of the peritoneum which extends from the
left colic flexure to the diaphragm opposite to the 10th rib.
2- Visceral surface of the spleen

Blood supply:

o Arterial Supply: by the splenic artery (branch from the coeliac trunk
o Venous drainage: the splenic vein that joins the superior mesenteric vein to form
the portal vein

Splenic artery
.

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The caecum
- The caecum: a blind pouch lying in the right iliac fossa.
- Its average length is 6 cm and its breadth 7.5 cm.
- It continues proximally with the ileum and distally with the ascending colon.
Relations:
- Posteriorly: right iliacus and psoas major muscles and the lateral cutaneous nerve of the
thigh.
- Anteriorly: completely covered by peritoneum and related to loops of the small intestine, the
greater omentum and the anterior abdominal wall.
The vermiform appendix

It is a narrow, vermiform (worm-like) tube about 2 cm long. It emerges from the

posteromedial wall of caecum below the ileocecal valve.

 It is suspended from the terminal ileum by the mesoappendix, which contains the
appendicular vessels.
 Its point of attachment to the cecum is consistent
with the highly visible free taeniae leading directly
to the base of the appendix, but the location of the
rest of the appendix varies considerably.
 It has several positions:
1. Retrocaecal (behind caecum) most common.
2. Pelvic, or descending (when appendix hangs
dependently over the pelvic brim, in close
relation to the Rt. uterine tube & ovary in ♀).
3. Sub-caecal (below caecum).
4. Pre- or post-ileal (anterior or posterior to the
terminal ileum respectively), are occasionally seen, especially when there is a long
appendicular mesentery which allows greater mobility.
 McBurney's point is located one third of the
distance from the right anterior superior iliac spine to
the umbilicus (navel). This point roughly
corresponds to the most common location of the root
of the appendix, where it is attached to the caecum.

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Anatomy of rectum
- The rectum is the terminal part of the large intestine.
- It is about 13 cm. (5 inches) long.
- It begins at the level of the S3 as a continuation of the sigmoid colon and ends at the
anorectal junction one inch in front of and below the tip of coccyx where it continues
as the anal canal .
- It is about 4 cm wide at its beginning (similar to that of the sigmoid colon) but it is
dilated near its end to form the rectal ampulla.
- Unlike other portions of colon, the rectum
does not have taeniae coli or sacculations.
Peritoneal coverings:
1. The upper 1/3 is covered by peritoneum
on front and sides
2. The middle 1/3 is covered by peritoneum
infront only.
3. The lower third has no peritoneal
coverings.
Flexures of the rectum:
1- Anteroposterior flexures
a. Sacral flexure (upper curve): concave forwards. It follows concavity of sacrum.
b. Perineal or recto-anal flexure (Lower curve): convex forwards. The rectum bents
backwards at the anorectal junction to form an acute angle of 80 degree. The
rectum pierces the pelvic diaphragm to continue as the anal canal.
2- Lateral flexures: the rectum has three lateral flexures (curves). The upper &lower
are convex to the right. The middle is the most prominent & convex to the left.
The mucosa of the rectum:
- It has longitudinal folds.
- There are 3 large transverse folds called rectal folds or shelves: known as Houston’s
valves. One-fold lies opposite the concave side of the 3 lateral flexures.
- These folds are about 12 mm. in width
- They contain circular muscle fibers to support the weight of fecal matter to prevent its
descent toward the anal canal as its presence always excites a sensation demanding its
discharge. In the empty state of the intestine these folds overlap each other.

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Relations: see practical

Arterial blood supply of rectum & anal canal:
1. Superior rectal artery: continuation of the inferior mesenteric artery.
2. Middle rectal artery: branch from the anterior division of the internal iliac artery.
3. Inferior rectal artery: branch from the internal pudendal artery, in the perineum, its
anastomosis with the middle rectal a. at anorectal junction.
Venous drainage of the rectum and anal canal: correspond to their arteries.
1. Superior rectal vein ends in the inferior mesenteric vein.
2. Middle rectal vein drains into internal iliac vein.
3. Inferior rectal vein: drain into the internal pudendal vein.

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Anatomy of anal canal

 It is the terminal part of the large intestine, it is about 2.5 to 4 cm.
 It begins at the anorectal junction one inch below and infront tip of coccyx.
 It extends in the anal triangle
downwards and backwards between the
ischiorectal fossae to end at the anal
orifice. It forms a posterior acute angle
about 80 degrees with the lower part of
the rectum.
 It has no peritoneal covering.
Relations: see practical
The internal features of anal canal:
 The anal canal is divided into upper
&lower parts by the pectinate line.
 The pectinate line represents the
embryological site of attachment of anal
Interior of the anal canal
membrane.
 The upper part extends from the anorectal junction to the pectinate line, while the
lower part extends from the pectinate line to the anal verge.
 The upper and lower parts of the anal canal are different in development, blood and
nerve supply and lymphatic drainage.
Features in the upper part of anal canal: The upper part of the anal canal (15 mm long)
presents the following features:
1. Anal columns (columns of Morgagni): These are permanent longitudinal mucous
folds numbering 6 to10. They contain radicles of the superior rectal vein.
2. Anal valves (valves of Morgagni): These are crescentic folds of the mucous
membrane which connect the lower ends of adjacent anal columns. The free margins
of these valves are directed upward. The position of these valves is indicated by the
wavy pectinate line (also called dentate line).
3. Anal sinuses: These are vertical recesses between the anal columns and above the
anal valves. The ducts of tubular anal glands present in the submucosa open in the
floor of anal sinuses.
Features in the lower part of anal canal: The lower anal canal is further divided into
two regions: upper and lower.

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a) Upper region (often called pecten): It is 15 mm long and extends from the pectinate
line to Hilton’s line. It is lined by the non-keratinized stratified squamous epithelium.
The mucous lining in this region appears bluish in colour due to underlying dense
venous plexus and is adherent to the underlying structures.
b) Lower region of lower anal canal: It is about 8 mm in extent and lined by the true
skin containing sweat and sebaceous gland. It shows pigmentation. In adult male,
coarse hairs are often found around the anal orifice. The junction between keratinized
& the non-keratinized parts is indicated by a whitish line called (Hilton's white line).
Anal sphincters:
1) The internal anal sphincter
It is a ring of circular smooth muscle fibers which surrounds the upper two thirds of
the anal canal. It is continuous with the circular muscle of the gut. Its thickness
ranges from 1.5 to 3.5 mm. It is thinner in females. It becomes thicker with age and
in chronic constipation.
Nerve supply: by the sympathetic and parasympathetic fibers. Both are distributed
via the inferior hypogastric plexus.
- Sympathetic fibers arise from the lower two lumbar segments of the spinal cord.
It causes contraction of the sphincter.
- Parasympathetic fibers arise from S2, 3, 4 spinal segments. It causes relaxation
of the sphincter.

A coronal section of anal canal showing internal and external anal sphincters
2) External sphincter: surrounds the lower two thirds of the canal. Thus, it overlaps the
internal sphincter in the middle third. It is formed from striated voluntary muscle fibers
arranged in three parts:
a) Deep part: It is a thick annular band that forms the true sphincter and has no bony
attachment.

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b) Superficial part: arises from the tip of coccyx and anococcygeal body and passes
forward around the sides of the anus to be inserted into the perineal body.
c) Subcutaneous part: surrounds the anal orifice and has no bony attachment.
Nerve supply: by the inferior rectal nerve and the perineal br. of 4th sacral nerve.
Lymph drainage of anal canal: upper half drains into pararectal lymph nodes and finally
into inferior mesenteric L.N. The lower 1/2 drains into superficial inguinal L.N.
Arterial supply of anal canal: The upper part is supplied by superior rectal a. & the
lower part is supplied by inferior rectal a.

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Anatomy of Ischiorectal fossa (Ischio-anal fossae)

Site & shape: a wedge-shaped, fat-filled space situated on each side of the anal canal
below the levator ani muscles. The 2 fossae communicate with each other behind anal
canal.

Functions: They help in dilatation of the anal canal, during defecation.

Measurements: each is 5 cm length x 5 cm width x 5 cm depth

Boundaries of the ischiorectal fossa

Boundaries:
Lat. wall * Fascia covering the obturator internus muscle
* ischium *sacrotuberous ligament
Med. wall *Fascia covering the levator ani muscle * external anal sphincter.
superiorly The medial & lateral walls converge
Anteriorly continuous with recesses that project into the urogenital triangle superior
to the deep perineal pouch.
Post.: Sacrotuberous ligament & on post. surface of which is gluteus maximus.
Floor: Perineal skin.
Contents
1. Ischiorectal pad of fat.
2. Inferior rectal nerves and vessels
th
3. Perineal branch of 4 sacral nerve
4. Posterior scrotal (or labial) nerves and vessels

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Anatomy of Liver
Site: The liver almost fully occupies the right hypochondrium, upper part of the
epigastrium, and part of the left hypochondrium up to the left lateral (midclavicular)
line. It lies mostly under cover of the ribs & costal cartilages immediately below the
diaphragm.
Shape: wedge-shaped and resembles a
four-sided pyramid laid on one side
with its base directed towards the
right & apex directed towards the Diaphragmatic surface of the liver.
left.
Surfaces: Surfaces of the liver include:
 Diaphragmatic surface: smooth,
dome-shaped, and lies against the
inferior surface of the diaphragm in
the anterior, superior, right, and
posterior (area of bare area proper)
directions.
Relation of the posterior and inferior surfaces of the
liver.
 Visceral surface: relatively flat or concave. It is separated in front from the
diaphragmatic surface by the sharp inferior border and lies in the posterior (small part)
and inferior directions.
Borders: the borders between surfaces are ill-defined except the inferior border which is:
 rounded laterally where it separates the right lateral from the inferior surfaces.
 thin and sharp medially where it separates the anterior surface from the inferior
surface.
 It presents two notches:
a) Notch for ligamentum teres: It is located just to the right of median plane.
b) Cystic notch: often corresponds to the fundus of the gallbladder.

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Anatomical lobes of the liver:

morphologically, the liver is divided into
small Lt. Lobe and larger Rt. Lobe (6 times
larger than the Lt. lobe) by:
 The attachment of the falciform
ligament on the diaphragmatic surface.
 The fissure for ligamentum venosum
on the posterior surface.
 The fissure for ligamentum teres on the
inferior surface.
N.B. The Rt. Anatomical lobe shows 2
smaller lobes:
Anatomical lobe of the liver.
1. Caudate lobe: is the part on the post.
surface, lying between groove for IVC to the right, fissure for ligamentum venosum
to the left & porta hepatis below.
 The caudate lobe has 2 processes: a papillary process, which arises from its left
side, and a caudate process above porta hepatis, which connects it to rest of liver.
2. Quadrate lobe is the part on the inferior surface, lying between: Fossa for
gallbladder to right, fissure for ligamentum teres to the left & porta hepatis: above

Ligaments: Ligaments of the liver are of two types: (a) false and (b) true.
a) False Ligaments: The false ligaments are peritoneal folds and include:
1. Falciform ligament: sickle-shaped fold.
2. Coronary ligament: It consists of two layers— upper and lower.
3. Right triangular ligament: It encloses the apex of the bare area of liver.
4. Left triangular ligament: It is a very-very small  fold.
5. Lesser omentum
b) True Ligaments: are the remnants of fetal structures and include:
1. Ligamentum teres hepatis: It is the remnant of the obliterated Lt. umbilical v.
2. Ligamentum venosum: It is the remnant of the obliterated ductus venosus.

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Relations of the liver:

Superior Surface: Related to the diaphragm which separates the liver from:
 Corresponding lung and pleura on either side
 Pericardium and heart in the center
Anterior surface:
- The falciform lig. is attached a little to the right of the median plane.
- It is Related to
 Xiphoid process and Anterior abdominal wall in the median plane
 The diaphragm on each side and costal margin
Right lateral surface: with diaphragm intervening, it is related to:
 Rt. Lung and pleura in the upper one-third
 Costo-diaphragmatic recess in the middle one-third
 10th and 11th ribs in the lower one-third
Posterior surface: This surface presents:
1. The bare area proper of the liver:
 A  area to the right of groove for the IVC between the 2 layers of coronary and
Rt. triangular ligaments.
 It is related to the diaphragm and the Rt. suprarenal gland.
2. The groove for IVC as the name indicates lodges the IVC. Its floor is pierced by
the hepatic veins.
3. The caudate lobe is related to superior recess of lesser sac.
4. The fissure for ligamentum venosum
5. Oesophageal impression: on the post. surface of Lt. lobe just to the left of the
upper part of fissure for lig. venosum & is related to abdominal part of
oesophagus.
Visceral surface (inferior surface):
1. The inf. surface of the Lt. lobe is related to:
a) Stomach (gastric impression): related to fundus & body’s upper part
b) lesser omentum: as the surface comes in contact with the lesser omentum, it
presents a slight elevation called omental tuberosity /tuber omentale. It lies
near the Lt. side of fissure for ligamentum Venosum.
2. The fissure for ligamentum teres.
3. The quadrate lobe is related to lesser omentum, the pyloric end of the stomach
and the first part of the duodenum and transverse colon

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4. Inf. surface of Rt. lobe related to: Fossa for gallbladder, Rt. colic flexure, upper
part of 2nd part of duodenum (duodenal impression) & Rt. kidney (renal
impression).
Porta hepatis
It is a horizontal fissure on the inferior surface of the liver between the quadrate and
caudate lobes. It represents the gateway of the liver and the main structures passing
through the porta hepatis (in the order from posterior to anterior [VAD]) are:
a) portal Vein
b) right & left branches of hepatic Artery
c) The right and left hepatic Ducts.
Porta hepatis also contains lymph nodes& nerves of the liver.

Blood supply: It receives blood from two sources:

 20%: arterial blood (oxygenated) supplied by the hepatic a.
 80%: venous blood (rich in nutrients) supplied by the portal v.
Venous Drainage: Most of the venous blood from liver is drained by 3 large hepatic
veins. They emerge in the groove for IVC and open directly in the IVC.

Lymphatic drainage: it has 2 sets of lymphatics:

 Superficial lymphatics: From the post. aspect of the liver, they drain into the
post. Mediastinal L.N. From the ant. aspect of the liver, they drain into 3-4 nodes
that lie in the porta hepatis (hepatic nodes).
 Deep lymphatics: are lymphatics that accompany the portal triads.
Nerve supply: The liver is supplied by both sympathetic and parasympathetic fibres:
 Sympathetic fibres: are derived from the coeliac plexus.
 Parasympathetic fibres: are derived from the hepatic branch of anterior vagal
trunk
Surface anatomy:
Upper Represented by line joining the following points:
border a) A point on the Lt.5th intercostal space at the Lt. midclavicular line
b) A point at the xiphi-sternal junction
c) A point on the Rt.5th rib at the Rt. midclavicular line
d) A point on the Rt.7th rib at the Rt. midaxillary line

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Lower Represented by line joining the following points:

th
border a) A point on the Lt.5 intercostal space at the Lt. midclavicular line
th
b) A point at the Lt. costal margin at the tip of the 8 costal cartilage
c) A point at the transpyloric plane in the middle line (level of L1)
th
d) A point on the tip of the 9 costal cartilage mid-clavicular line
(related to fundus of gallbladder)
th
e) A point on the Rt.11 rib at the Rt. midaxillary line
Rt. Border Represented by line joining the following points:
th
a) A point on the Rt.7 rib at the Rt. midaxillary line
th
b) A point on the Rt.11 rib at the Rt. midaxillary line

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Extrahepatic biliary apparatus

It receives the bile from liver, stores and concentrates it in the gallbladder, and transmits
it to the second part of the duodenum when required. It consists of 5 components:
1- Rt. & Lt. hepatic ducts: The Rt. & Lt. hepatic ducts drain bile from the Rt. & Lt.
lobes of the liver.
2- Common hepatic duct: a 1-inch duct that joins the cystic duct to form the common
bile duct (CBD).
3- Gallbladder.
4- Cystic duct.
5- Bile duct (formerly, common bile duct).

Gallbladder: is an elongated pear-shaped sac of about 30–50 ml capacity. It stores,

concentrates the bile & discharges it into duodenum by its muscular contraction.
Location: gallbladder lies in fossa for gallbladder on inferior surface of Rt. lobe of liver.

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Dimensions: 10 cm Length and 3 cm Width (at its widest part)

 Parts and Relations: The gallbladder is divided into the 3 parts:
1. Fundus (expanded lower end that projects below the inferior border of liver):
Related anteriorly to the ant. abdominal wall at the tip of Rt. 9th costal cartilage. It
is completely surrounded by peritoneum.

Body: Its upper surface is related directly to the liver and is devoid

2. of the peritoneum. Its undersurface is covered by the peritoneum and is related to

transverse colon and the superior part of the duodenum.
3. Neck (narrow end).: It joins the cystic duct and its junction with this duct is marked
by a constriction. It is related inferiorly to the 1st part of the duodenum. The
posteromedial wall of the neck shows a pouch-like dilatation (Hartmann’s pouch).
The gall stones lodged in this pouch may cause adhesion with the 1 st part of the
duodenum and may perforate it.

Blood supply of gall bladder:

 Arterial Supply: the cystic a. (a branch of Rt. hepatic a.).
 Venous Drainage: The venous drainage of the gallbladder is dual:
 by the cystic vein, which drains into the portal vein.
 by several small veins, which pass directly to the liver.

Lymphatic Drainage: cystic & hepatic L.N.

Nerve Supply
 Sympathetic fibres (T7–T9) via cystic plexus.
 Parasympathetic fibres from the (Rt.& Lt. vagus nerves)
 Sensory: Rt. phrenic n. (thus gallbladder pain is referred to the tip of the Rt. Shoulder)

Cystic duct: It is s-shaped, about 3–5 cm long.

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course of the common bile duct.

Bile duct/common bile duct (CBD): It is usually 7.5 cm (3 inches) long and about 6 mm
in diameter.
Parts: is divided into 4 parts: -
o Supra-duodenal: It descends in the Rt. free margin of the lesser omentum to the
right of the hepatic artery proper and anterior to the portal vein.
o Retro-duodenal: It descends behind the first part of the duodenum.
o Infra-duodenal (or pancreatic): It runs in the groove on the post. Surface of the
head of pancreas and is sometimes completely embedded in the pancreatic tissue.
o Intra-duodenal (or Intramural): The terminal part and the main pancreatic duct both
enter the posteromedial wall of the 2nd part of duodenum at the same site a little
below to its middle. They join each other to form an expansion, the
hepatopancreatic ampulla (or ampulla of Vater) which open on top of the major
duodenal papilla (10 cm distal to the pylorus).

Arterial Supply of the Bile Duct/Common Bile Duct

 The upper part by cystic artery.
 The lower part by superior pancreaticoduodenal artery.

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Arterial blood supply of the GIT

The abdominal parts of the gastrointestinal system are supplied mainly by the celiac trunk
and the superior mesenteric and inferior mesenteric arteries.
1. The celiac trunk supplies the foregut: the lower oesophagus, stomach, superior part of
the duodenum, and proximal half of the 2nd part of the duodenum.
2. The superior mesenteric artery supplies the midgut: the rest of the duodenum, the
jejunum, the ileum, the ascending colon, and proximal 2/3 of transverse colon.
3. The inferior mesenteric artery supplies the hindgut: the rest of the transverse colon, the
descending colon, the sigmoid colon, and most of the rectum.
Celiac trunk (artery of foregut)
Origin: from the abdominal aorta immediately below the aortic hiatus of the diaphragm,
usually at the level of the vertebral body of T12.

Branches: It immediately divides into the left gastric, splenic, and common hepatic
arteries.
 Left gastric artery is the smallest branch of the celiac trunk. It ascends to the
cardio-oesophageal junction then descends along the lesser curvature of stomach and
ends by anastomosing with the right gastric a.
Branches:
a. oesophageal branches to the abdominal
part of the oesophagus.
b. Gastric branches: to both surfaces of
the stomach along the lesser curvature
 Splenic artery: the largest branch of the
celiac trunk. It takes a tortuous course to
the left along the superior border of the
pancreas. It enters the lienorenal lig.
through which it reaches the hilum of
spleen where it divides into five or more
segmental branches, which enter the hilum
of the spleen to supply it. Branches of the splenic artery.

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Branches:
a. Pancreatic branches: numerous small branches, supply whole of the pancreas
except the head.
b. Short gastric branches (3–7 in number)
pass through the gastrosplenic ligament to
stomach’s fundus.
c. Lt. gastro-epiploic artery runs along the
greater curvature of stomach terminates by
anastomosing with the right gastroepiploic
artery.
d. Terminal splenic branches
 Common hepatic artery: a medium-sized
branch that runs to the right and divides into its
two terminal branches at the upper border of
duodenum, hepatic artery proper and

gastroduodenal artery: Branches of the hepatic artery.

1. The hepatic artery proper ascends toward the liver in free edge of lesser
omentum. On reaching porta hepatis, it terminates by dividing into Rt. & Lt.
hepatic arteries.
Branches:
I. The right gastric artery, but it can also arise from the common hepatic
artery (Fig.83). It passes to the left and ascends along the lesser curvature of
the stomach in the lesser omentum, and anastomoses with the left gastric a.
II. Terminal branches: right and left hepatic arteries near porta hepatis.
III. The right hepatic artery gives off the cystic artery to the gallbladder.
2. The gastroduodenal artery, it runs downward behind the duodenum
&terminates at its lower border it gives off:
Branches:
I. The Sup. pancreaticoduodenal a. and that supply the head & uncinate
process of the pancreas and the duodenum. It divides into Ant. &Post.

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branches that eventually anastomose with those of the inf.
pancreaticoduodenal artery.
II. The Rt. gastroepiploic a. that passes to the left, along the greater curvature
of the stomach, eventually anastomosing with the Lt. gastroepiploic a.

Superior mesenteric artery (artery of midgut)

Origin: from the abdominal aorta immediately below the celiac artery, at the level of the
L1 vertebral body.

Course: it runs downward and to the right to enter the root of mesentery where it runs
between its two layers. Throughout its course, it is accompanied by the sup.
mesenteric vein on its right side.
Relations:
Anteriorly it is related to the body of pancreas and splenic vein.
Posteriorly from above
downward it is
related to the lt.
renal vein, uncinate
process of the
pancreas, 3rd part
of the duodenum,
IVC, right ureter,
and right psoas
major (see relations
of the 3rd part of
duodenum).
End: It terminates in the right
iliac fossa by
anastomosing with a
branch of ileocolic
artery—one of its own branches.
Branches: The superior mesenteric artery gives off five sets of branches. All branches
arise from its right side except jejunal & ileal branches which arise from its left side
as follows:

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1. Inf. Pancreatico-duodenal a.: 1st branch arising from the Rt. side and soon divides
into Ant. and Post. branches.
2. Middle colic a.: It runs upward and forward to pass between the two layers of
transverse mesocolon, where it divides into Rt. and Lt branches.
 The Rt. branch Superior mesenteric artery, its branches and distribution.
anastomoses with
ascending br. of the Rt. colic a.
 The Lt. branch anastomoses with ascending br. of the Lt. colic a.
3. Rt. colic a.: It runs to the right behind the peritoneum and divides into ascending and
descending branches.
 The ascending br. anastomoses with Rt. branch of middle colic a.
 The descending br. anastomoses with the ascending br. of ileocolic a. to form
beginning of marginal artery of Drummond.
4. Ileocolic a.: It is the final branch arising from the Rt. side. It passes downward and to
the right toward Rt. iliac fossa where it divides into ascending & descending branches.
 The ascending br. anastomoses with descending br. of Rt. colic a.
 The descending (inferior) br. anastomoses with the terminal end of sup. mesenteric
artery. The descending/inferior branch of the ileocolic artery also gives rise to:
a. Ant. & post. caecal arteries to the caecum.
b. Appendicular a. enters the free margin of and supplies mesoappendix &
appendix.
c. Ileal branch to the terminal part of the ileum before anastomosing with the
superior mesenteric artery
5. Jejunal & ileal branches:
 about 12–15 in number arising from the convex Lt. side of the artery.
 They supply the jejunum and most of the ileum.
 They pass between two layers of the mesentery, where They branch and
anastomose with each other to form a series of arterial arcades from which further
branches arise and form the second, third, and even fifth tiers of arterial arcades.
 Arterial arcades:
- The number of these arcades increases from the jejunum (1-2 arcades) to
ileum.

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- vasa recta (straight
arteries): Extend from
the terminal arcade
and provide the final
direct vascular supply
to the walls of small
intestine.

Inferior mesenteric artery

(artery of hindgut)
Origin: the smallest of the three
anterior branches of the
abdominal aorta. It arises
anterior to the body of
vertebra L3.

Course & End: Initially, the

inferior mesenteric artery
descends anteriorly to the
aorta and then runs downward and to the left to cross the termination of the Lt.
common iliac a. (medial to ureter) at which point it becomes superior rectal artery.

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Branches:
1. Left colic artery: It divides into ascending and descending branches:
a. The ascending br.
b. The descending branch anastomoses with the 1st sigmoid a.
2. Sigmoidal arteries: The sigmoid arteries consist of 2-4 branches and descend to the
left, in sigmoid mesocolon.
3. superior rectal artery: The continuation of the inferior mesenteric artery. It
descends into the pelvic cavity in the sigmoid mesocolon. Opposite vertebra S3, the
superior rectal artery divides into 2 terminal branches descend on each side of the
rectum. At the level of the
internal anal sphincter,
end by anastomosing
along the way with
Inferior mesenteric artery, its branches and distribution.
branches from the middle
rectal arteries (from the
int. iliac a.) and the
inferior rectal arteries
(from the int. pudendal
a.).

Marginal Artery of
Drummond:
Arterial supply of colon & formation of marginal a. of Drummond.
 It is a circumferential
anastomotic arterial channel extending from the ileocaecal junction to the
rectosigmoid junction.
 It is located close (about 3 cm) to inner margin of colon.
 It is formed by the anastomoses between the branches of colic branches of the
superior mesenteric artery (i.e., ileocolic, right colic, and middle colic) and colic
branches of the inferior mesenteric artery (left colic and sigmoidal). The vasa recta
arise from the marginal artery and supply the colon.

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Portal circulation
Length of portal vein: about 3 inches (7.5 cm) in length
The important features of
the portal vein are:
1. It provides about 80%
of the blood that flows
through liver.
2. Its tributaries &
branches contain up to
1/3 of the total volume
of blood in the entire
body.
3. The portal vein & its
tributaries are devoid of
valves. Formation of the portal vein behind the neck of the pancreas.

Formation: is formed behind the neck of pancreas by the union of superior mesenteric
vein and splenic vein at level of L1.
End: It ends at the right end of porta hepatis by dividing into right & left branches.
Course and parts:
For description, the portal vein is divided into 3 parts in relation to the 1 st part of
duodenum:
1. Infra-duodenal part: behind the Neck of pancreas & infront of IVC.
2. Retro-duodenal part: which lies posterior to the 1st part of the duodenum & in
front of IVC.
3. Supra-duodenal part: which lies in the right free margin of lesser omentum.
N.B. Intrahepatic course: After entering the liver, each branch of the portal vein
divides and redivides, like those of the hepatic artery to end ultimately into the hepatic
sinusoids. Here the portal venous blood mixes with the hepatic arterial blood. From
hepatic sinusoids the blood is drained by hepatic veins into the IVC.

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Tributaries:
1. Splenic vein (which receives the inferior mesenteric v.).
2. Superior mesenteric vein.
3. Superior pancreaticoduodenal vein.
4. Left and right gastric veins. The left gastric vein receives a few oesophageal veins
from the lower end of oesophagus.
5. Cystic vein joins the right branch of the portal vein before it enters the liver.
6. Paraumbilical veins (of Sappey) are small veins that join the left branch of the
portal vein before it enters the left lobe of the liver.
Portocaval (Portosystemic) Anastomoses:
- There are many sites where anastomosis exists between portal and systemic venous
systems. These communications form important routes of collateral circulation in
cases of portal obstruction.
- The important sites of portocaval anastomoses are as follows:
1. Lower third of the oesophagus:
Anastomosis Portal: Oesophageal tributaries of left gastric vein
between Systemic: Oesophageal tributaries of accessory hemiazygos vein
Clinically: In portal obstruction, these collateral channels become distended
and tortuous, forming oesophageal varices.
2. Umbilicus:
Anastomosis Portal: Paraumbilical veins
between Systemic: Superficial veins of anterior abdominal wall
Clinically: In portal obstruction, the superficial veins around the umbilicus
become distended and tortuous (varicosity) (snake like) forming
Caput medusae
3. Mid-anal canal
Anastomosis Portal: Superior rectal vein
between Systemic: Middle and inferior rectal veins
Clinically: The distension and dilatation of these anastomotic channels
result in the formation of haemorrhoids or piles which may be
responsible for repeated bleeding per annum.

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Sites of portosystemic anastomosis: 1=lower end of the esophagus, 2=anal canal, 3= in the region of the
umbilicus, 4= at the bare area of the liver, 5=between the colic veins and the renal veins.

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Splanchnic Circulation

 The liver and viscera receive about 30% of the cardiac output via celiac, superior
mesenteric, and inferior mesenteric arteries.
 The liver receives about 1000mL/min from the portal vein and 500mL/min from the
hepatic artery.
 The blood from the intestine, pancreas, and spleen drains via the hepatic portal vein
to the liver and from the liver via the hepatic veins to the inferior vena cava.

Intestinal Circulation:

 The intestines are supplied by a series of parallel circulations via branches of the
superior and inferior mesenteric arteries.
 The blood flow responds to changes in metabolic activity. Thus, blood flow to the
small intestine and hence blood flow in the portal vein doubles after meals and the
increase lasts up to 3 hours.
 The intestinal circulation is capable of extensive autoregulation.

Hepatic Circulation:

 The functional unit of the liver is the acinus. The human liver contains about 100,000
acini. Each acinus is at the end of a vascular stalk containing terminal branches of
portal veins, hepatic arteries, and bile ducts. The hepatic veins drain into the inferior
vena cava.

 Portal venous pressure is normally about 10mmHg, the mean pressure in the hepatic
artery branches is about 90 mmHg and the hepatic venous pressure is about 5mmHg.

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There is an inverse relationship between hepatic arterial and portal venous blood
flow.

 The intrahepatic portal vein radicles have smooth muscle in their walls that is
innervated by noradrenergic vasoconstrictor nerve fibers reaching the liver via the
third to eleventh thoracic ventral roots and the splanchnic nerves. The vasoconstrictor
innervation of the hepatic artery comes from the hepatic sympathetic plexus. There
are no known vasodilator fibers reaching the liver. Conversely, when there is diffuse
noradrenergic discharge in response to a drop in systemic blood pressure, hepatic
blood flow may be reduced to such a degree that there is patchy necrosis of the liver.

Reservoir function of the Splanchnic Circulation:

The reservoir function of the whole visceral circulation is important. For example,
25-30% of the volume of the liver is accounted for by blood and contraction of the
capacitance vessels in the viscera can pump a liter of blood into the arterial
circulation in less than a minute. During severe exercise, constriction of the vessels in
these organs and decreased blood storage in the splanchnic bed, the skin and the lungs
may increase the volume of actively circulating blood perfusing the muscles by as
much as 30%.

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