Pelvis, perineum and

extraperitoneal space
Anatomy lab session, edition 2022.
by Prof. Jerzy Gielecki MD, PhD and Anna Żurada MD, PhD

1 Extraperitoneal space and its organs

1.1 Posterior group of the abdominal muscles
Discussed int the abdomen lab session.

1.2 Kidneys
Paired kidneys are responsible for removal of useless products of protein metabolism and excess of salts
and water from the blood. The kidneys in adult measure about 10-12 cm in length, 5-6 cm in width and 2.5
-3.5 cm in thickness.

Fig. 1.1. Topographical relations of kidney

1.2.1 Localisation of the kidneys

Kidneys lay on the posterior abdominal wall (on the level between Th11-L3) and they are situated
retroperitoneally (posteriorly to the peritoneum), both of them are in contact with the diaphragm

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(posterosuperiorly) and are capped by the adrenal gland (anteromedially). Each kidney is obliquely set
because its upper pole is nearer the midline (3.5-4cm) than its lower pole (5.5-6 cm). Superior poles of
both kidneys are protected by thoracic cage. The right kidney lies on the slightly lower level then the left
one, due to the presence of the liver on the right side. The left kidney's upper pole extends above the
posterior segment of the eleventh rib. The superior pole of the right kidney extends above posterior
segment of the right twelfth rib.

Each kidney is located:

1. On the ventral surface of the quadratus lumborum muscle.
2. Laterally to the psoas major muscle and the vertebral column.
The kidney has:
1. Upper & lower poles
2. Anterior & posterior surface
3. Lateral (convex) & medial (concavity with renal sinus)

1.2.2 Renal hilus

The concave medial border of the kidney contains the renal hilus (hilum, hilus renalis), through which the
renal pelvis and vein leave the kidney, and also the renal artery enters there to the kidney. The hila are
located about the level of the transpyloric plane. At the hilus opens medially the renal sinus, the cavity of
the kidney. The renal vessels and the renal pelvis, the distended pre-ureteric portion of the urinary tract,
are arranged in the following order:
1. Superior to inferior, at the renal hilum:
a. Renal vein
b. Renal artery
c. Renal pelvis
2. Anterior to posterior, at the renal hilum:
a. Renal vein
b. Renal artery
c. Renal pelvis

1.2.3 Relations of the kidneys

Both kidneys have similar posterior relations:
Diaphragm separates the upper pole from the costodiaphragmatic recess of pleura (superior one-third
area).
Below there are three muscular areas from the medial to lateral:
1. Psoas major
2. Quadratus lumborum
3. Transversus abdominis

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Fig. 1.2. Anterior relations of kidneys

The left kidney is related anteriorly to:

1. Area of the suprarenal gland (anteromedially)
2. Area of the stomach
3. Area of the pancreas (tail)
4. Area of the spleen
5. Area of the jejunum
6. Area of the splenic flexure of the colon

The right kidney is related anteriorly to:

1. Area of the suprarenal gland (anteromedialy)
2. Area of the duodenum (2nd part)
3. Area of the liver
4. Area of the jejunum
5. Area of the hepatic flexure of the colon

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Fig. 1.3. Posterior relations of kindeys

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1.2.4 Structure of the kidneys
1.2.4.1 Capsules
The kidney has two capsules, false an true:
1. False capsule (of Gerota) or perirenal fascia. This layer arises from the prevertebral fascia. It divides
into two layers:
a. anterior layer
b. posterior layer
The fascia splits inferiorly into two leaflets and fuse superiorly and lateraly for enclosing the kidney
and suprarenal gland. It sourounds the kidney and suprarenal gland.
The renal fat is associated with the kidney and it also sourounds kidney and suprarenal gland and it
is called fat capsule.
The renal fascia fuses around the renal vessels and forms the periuretral sheath.
2. The true fibrous renal capsule separates the kidney from the suprarenal gland.
1.2.4.2 Internal structure
The kidney is divided into two parts: cortex and medulla.
1. Cortex is composed of:
a. Renal corpuscles
b. Proximal convoluted tubules
c. Distal convoluted tubules
2. Medulla is formed by 10 -20 renal pyramids. Every pyramid contains:
a. Proximal straight tubules
b. Henle's loops
c. Distal straight tubules
d. Collecting tubules
1.2.4.3 Collecting system
The collecting system of the kidney is composed of three elements:

1. Minor calyces, which fuse and join to form 2-4 major calyces.
2. Major calyces, which fuse and join to form renal pelvis.
3. Renal pelvis, which narrows to form the ureter.
The urine empties into minor calyces from the collecting tubules. The minor calyces envelop the renal
papillae and urine pierces the tip of the renal papillae.

1.2.5 Arterial supply of the kidney

The renal arteries arise from the lateral aspect of the abdominal aorta and divide into branches near the
hilum. The left and right renal arteries arise usually between L1 and L2, just below origin of the superior
mesenteric artery. The right renal artery passes posteriorly to the inferior caval vein.
The left and right renal arteries give rise to the inferior suprarenal arteries outside the kidney and the
arterial twigs to the ureter.
The renal arteries divide into segmental arteries (arterie segmentales) within the renal sinus.

This division defines five segments:

1. Superior segmental artery

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 2. Anterior-superior segmental artery
3. Anterior-inferior segmental artery
4. Inferior segmental artery
5. Posterior segmental artery
Interlobar arteries arise from each segmental artery. Each interlobar artery enters a renal column. Each
gives off the arcuate arteries, which run across the bases of the pyramids between the cortex and medulla.
Arcuate arteries give of the interlobular arteries, which course between the medullary rays.
Interlobular arteries supply the afferent glomerular arterioles.

1.2.6 Venous drainage of the kidneys

1. Right renal vein enters the inferior vena cava at the lower point then the left renal vein. It usually
has no significant tributaries.
2. Left renal vein is longer than the right and crosses anteriorly the abdominal aorta.
It receives:
a. Left gonadal vein
b. Left suprarenal vein
c. Left inferior phrenic vein
d. Communicates with the accesory azygos vein

1.2.7 Lymphatic drainage of the kidneys

All lymph drain to the renal lymphatic nodes and next to the lumbar lymphatic nodes.

1.2.8 Innervation of the kidneys

The kidneys are supplied by the coeliac plexus, which gives fibres (sympathetic fibres from coeliac plexus
and parasympathetic fibres from cranial nerve X) to the renal plexus.

1.3 Ureters
The ureters (ureteres) are the excretory tubes which convey urine from the kidneys to the bladder. The
ureters are thick-walled, muscular tubes in which peristaltic waves occur at that time when urine passes
along the tube. They are 25-30 cm long. Each ureter descends retroperitoneally from the renal pelvis (L2)
to the urinary bladder (S4).
Course of each ureter has two stages:
a. Abdominal part
b. Pelvic part
In the abdomen, each ureter descends retroperitoneally and in its abdominal course the ureter courses
anteriorly to the psoas major muscle, then crosses over the proximal part of the external iliac a. from
lateral to medial side, to enter the cavity of the true pelvis. The gonadal vessels cross anteriorly to the
middle 1/3 of the ureters. The right ureter descends close to the right margin of the I.V.C. while the left
ureter passes inferiorly under the descending colon. After crossing over the pelvic brim, near the sacral
promontory (promontorium, level of L5/S1), the ureter enters the cavity of the true (lesser) pelvis. The
pelvic portion of the ureter runs along the lateral wall of the true pelvis, then it turns medially to enter the
posterior aspect (the fundus) of the urinary bladder. In females, the ureter passes deeply to the uterine
vessels, near the ischial spine, a place of great danger during hysterectomy procedures.
Mnemonic: Bridge (ductus deferens) over water (ureter).
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1.3.1 Relations of the two parts of the ureter
1. Abdominal part is similar in male and female bat the relations of two sides differ:
a. Right ureter has the following relations:
• Posterior to the descending portion of the duodenum.
• it lies posteriorly to root of mesentery proper.
• it is posterior to the right gonadal vessels.
b. Left ureter has the following relationships:
• it is posterior to the left colic vessels.
• it is adjacent to the left gonadal vessels.
• it lies posteriorly to sigmoid mesocolon.
2. Pelvic part:
a. in the male it crosses:
• Common iliac vessels in front of the sacroiliac joint.
• Vas deferens posteriorly.
b. in the female is crossed superiorly by:
• Uterine artery.
The following table provides the anterior and posterior relations of the abdominal portion of the ureters:

Right ureter anterior relations Left ureter anterior relations

Peritoneum Peritoneum
Duodenum Sigmoid
Ileum Sigmoid
Root of mesentery of small intestine Sigmoid mesocolon
Right colic and ileocolic vessels Left colic vessels
Gonadal vessels (testicular/ovarian) Gonadal vessels (testicular/ovarian)
Right ureter posterior relations Left ureter posterior relations
Psoas major muscle Psoas major muscle
Genitofemoral nerve Genitofemoral nerve
Bifurcation of external iliac artery Bifurcation of common iliac artery
Fig. 1.4. Relations of the ureters

1.3.2 Constrictions of the ureters

The ureters display three constrictions:
1. At the constriction of the renal pelvis to become the ureter proper.
2. Near the sacral promontory (level of S1), where the ureter crosses the pelvic brim to enter the true
(lesser) pelvic cavity.
3. At the fundus where the ureters perforate the musculature of the urinary bladder. The three
ureteric constrictions become problematic when renal calculi are passed to the bladder.

1.3.3 Arterial supply of the ureters

The blood supply of the ureters is highly variable. Each ureter can be supplied by:
1. Arterial twigs from the renal arteries
2. Abdominal aorta
3. Small arteries of the posterior abdominal wall
4. Gonadal arteries
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 5. Common and internal iliac arteries (ureteric branches)
6. Inferior vesical arteries

1.4 Suprarenal glands

Two suprarenal endocrine glands are situated on the upper poles of the kidneys. They are asymmetrical.
The right gland is pyramidal in shape and lies in the front of the right crus of the diaphragm behind the
inferior vena cava and bare area of the liver. The left is crescent and its lower end reaches the hilum of the
kidney. It lies in the front of the left crus of the diaphragm, and behind the splenic vessels and the
pancreas.

1.4.1 Arterial supply of the suprarenal glands

Suprarenal arteries arise from three sources:

1. Superior suprarenal arteries arise from the inferior phrenic artery which is paired parietal aortal
branch.
2. Middle suprarenal arteries arise directly from the abdominal aorta.
3. Inferior suprarenal arteries arise from each renal artery.

1.4.2 Venous drainge of the suprarenal glands

Suprarenal vein exits at the hilus of each suprarenal gland.
1. Right suprarenal vein (vena suprarenalis dextra) drains to the inferior vena cava.
2. Left suprarenal vein (vena suprarenalis sinistra) drains usually to the left renal vein.

1.5 Urinary bladder

The main function of the highly muscular urinary bladder is storage of urine to an average capacity of 500
ml. It is located within the true pelvic cavity, rests on the lining of the inner aspect of the pubis and floor of
the pelvis. The superior surface of the empty bladder reaches the pubic crest, and as the organ fills with
urine it distends superiorly into the abdominal cavity to reach, under extreme conditions, the umbilical
region. The superior surface of the bladder is covered with a sheet of peritoneum which continues with the
peritoneal reflections over the uterus, in the female, and along the upper anterior surface of the rectum in
the male. The bladder shape vary with the amount of the urine it contains and also is determined by
organs, which are closlely related to it.

Fig. 1.5. Schematic drawing of the urinary bladder.

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1.5.1 Structure of the urinary bladder
Urinary bladder has:
1. Apex – anterior end of the urinary bladder. The median umbilical ligament (remanat of the
embryonic urachus) arises from the apex and (enclosed in the peritoneum) forms the median
umbilical fold.
2. Neck – inferolateral part connecting the apex and the body.
3. Body.
4. Fundus of the urinary bladder (base) – posteroinferior surface.

1.5.1.1 Composition of the walls of the urinary bladder

The wall of the bladder consists of the muscular part (smooth muscles) and the mucous membrane.

1. Mucous membrane is loosly connected to the muscular layer exept the area located in the fundus,
which is triangular in shape and is called trigone of the bladder. The ureteric orifices are located in
the two upper angels of the trigone of the bladder. The interureteric fold is sutuated horizontaly
between them. In the lower angle of the trigone of the bladder there is the internal urethral orifice.
2. Muscular wall consists of three layers (fibres of each of them penetrate to the others):
a. External longitudinal layer
b. Circular layer
c. Internal longitudinal layer
The smooth muscles of all layers form the detrusor muscle. Fibres of all layers run toward to the
neck of the bladder and form the internal sphincter.

1.5.2 Relations of the bladder

1. The superior surface of the bladder in the male is covered by the peritoneum and comes in contact
with coils of the small intestine. In the female, with an empty bladder, the superior surface of the
organ is overlapped by the uterus.
2. The two inferolateral surfaces of the bladder are positioned against the fat-filled retropubic space
which is traversed by a multitude of veins (prostatic or vesical tributaries of the internal iliac vein).
The inferolateral surfaces of the bladder meet at the neck of the organ which relates to the
prostate, in the male, and the pelvic diaphragms (pubococcygeal part of the levator ani muscles) in
the female pelvis.
3. The posterior surface or the base of the bladder is related to the seminal vesicles and ampullae of
ductus deferens and rectum in the male pelvis. In the female, the base relates to the anterior wall
of the vagina and to the supravaginal part of uterine cervix.

1.5.3 Arterial supply of the urinary bladder

The urinary bladder is supplied by branches from internal iliac artery:
1. Superior vesical arteries, from the functional part of umbilical artery – branch from the internal
iliac artery. There can be multiple (i. e. two) superior vesical arteries branching off the umbilical
artery.
2. Inferior vesical arteries, which usually branch off directly from the anterior trunk of internal iliac
atrtery.

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1.5.4 Venous drainage of the urinary bladder
All veins from bladder drain into the internal iliac vein and correspond to adequate arteries. The vesical
venous plexus envelops the base of the bladder and prostate and comunicates freely with the prostatic
plexus in male, the veins from the seminal vesicles, and ductus deferentes.

1.5.5 Lymphatic drainage of the urinary bladder

From the superior part of the bladder lymph drains into external iliac lymphatic nodes (nodi lymphatici
iliaci externi), and next to the common iliac nodes (nodi lymphatici iliaci communes). From the inferior part
of the bladder lymph drains into the internal lymphatic nodes (nodi lymphatici iliaci interni), and next to
the common iliac nodes.

1.6 Urethra
The main function of the urethra is to convey urine from the bladder to the external environment -
external urethral orifice, and to allow the passage of sperm between the prostate and the tip of the penis
during ejaculation in male. In male it also provides seminal fluid. The male urethra is represented by a 15 -
20 cm long passage lined by a few types of epithelium. The normal transverse width of urethra, 5 to 6 mm,
can be stretched up to 26 mm for examination of the urinary tract and bladder.

1.6.1 Male urethra

The male urethra can be subdivided into three functional parts:
1. Prostatic – 2.5 to 4.5 cm long, the prostatic urethra extends between the internal urethral orifice
and the superior fascia of the urogenital diaphragm. It passes through the prostata downwards as a
anteriorly concave curve. This part is the widest and dilatable part of the male urethra, which is
narrowest in the superior and inferior segmnet of the prostatic urethra.
2. Membranous – 1.0 to 1.5 cm long, goes via urogenital diaphragm.
3. Spongy – 14 to 15 cm - the longest part of the urethra passes through the root and body of the
penis, within corpus spongiosum of the superficial perineal pouch.

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Fig. 1.6. Course and relations of the male urethra.

Fig. 1.7. The beginning part of the male urethra opened and seen from above. *Prostatic utricle is a homologue of the vagina and uterus.

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Fig. 1.8. The male urethra.

1.6.1.1 Bulbourethral glands

The bulbourethral glands of the male are located on either side of the urethra as the latter passes between
the muscular fasciculi of the sphincter urethrae muscle of the deep perineal pouch.

1.7 Female urethra

The female urethra is a 4 cm long and 5 mm width muscular tube. The superior part of the female urethra
is coresponding to the prostatic part of the male urethra and inferior part is adequate to the membranous
part. The female urethra originates in the apex of the urinary bladder, passes posteriorly, and next
inferiorly to the pubic symphysis. The female urethra lies anteriorly to the vagina and ends in the vestibule
of the vagina as external urethral orifice, which is located between the labia minora, below the clitoris and
in front of the vaginal opening. It is surrounded there by the sphincter urethrae muscle. The female urethra
with the vagina passes through the uretrogenital diaphragm and the perineal membrane.
The female urethra can be divided into four parts:

1. Intramural (intraparietal) portion – inside the bladder's wall.

2. Supradiaphragmatic portion – above the uretrogenital diaphragm, runs along the anterior wall of
the vagina.
3. Diaphragmatic portion – surrounded by the sphincter urethrae muscle.
4. Infradiaphragmatic portion - between the paraurethral glands.
There are the paraurethral glands (glandulae paraurethrales) on each side of the female urethra, which are
homologous to the prostate in male. The ducts from the paraurethral glands open near the external
urethral orifice in the vestibule of the vagina.

1.8 Internal iliac artery

Internal iliac artery is a major artery in the pelvic cavity, which supplies all pelvic viscera, perineum and
postero-anterior side of the thigh.

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Origin: It's origin is located in front of the sacroiliac joint on the L5 level, as the terminal branch of the
common iliac artery.
End: It divides into two terminal branches: inferior gluteal artery and internal pudendal artery.
Course: It passes downwards and behind the internal iliac vein (located behind and partly medially to the
artery) along the pelvic wall and is covered medialy by the parietal peritoneum.

1.8.1 Branches of internal iliac artery

Heads up!
The exact branching pattern of the internal iliac artery remains significantly variable, and during the
dissection classes will differ depending on the particular specimen. Therefore, different artery origin
scenarios are given below.

Internal iliac artery gives off numerous branches, grouped in two trunks (divisions): anterior and posterior.
1. Anterior trunk supplies the pelvis and visceral organs. It usually continues the trajectory of the
internal iliac artery itself, and runs towards the ischial spine. It ends near the lower part of the
greater sciatic foramen. It gives off visceral and parietal branches.
2. Posterior trunk supplies pelvic parietal structures (therefore, gives off only parietal branches). Just
after arising it runs to the posterior side of the pelvic cavity and reaches the upper part of the
greater sciatic foramen, above the piriformis.

1.8.1.1 Branches of the anterior trunk of internal iliac artery

Most of the branches of the anterior trunk supply pelvic viscera. Obturator artery and inferior gluteal
artery are parietal branches.

1. Umbilical artery, which is partly closed after birth and continues as obliterated umbilical artery. The
obliterated part of umbilical artery forms medial umbilical ligament in adults. Eventually, medial
umbilical ligament lays foundation to the medial umbilical fold.
The remaining functional part of the umbilical artery gives off:
a. Superior vesical artery/arteries (single or multiple branches). Supplies the bladder, distal
ureter, and in males: part of ductus deferens and seminal vesicles.
2. Inferior vesical artery, In male it gives off the prostatic branch. Both the superior and inferior
vesical arteries supply the urinary bladder. In female it partly supplies the vagina, thus being called
vaginal artery (not to be confused with the vaginal branch of the uterine artery).
3. Arteries dependable on sex:
a. Female: Uterine artery. Arises below the obturator artery and/or near the umbilical artery.
The uterine artery supplies the uterus, vagina, ovary and uterine tube. It pasess into the
isthmus of the uterus, where the vaginal branch arises and crosses anteriorly the ureter.
Near the margin of the uterus the uterine artery ascends along the lateral margin of the
uterus (there it gives off uteral branches), and next it divides into terminal branches:
• ovaric branch.
• tubal branch.
b. Male: Artery of the ductus deferens. Artery of the ductus deferens passes to the spermatic
cord. It has variable origin: can arise from superior or inferior vesical artery, and also from
the umbilical artery or even from the anterior trunk directly.
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 4. Middle rectal artery, which anastomoses with the superior and inferior rectal arteries.
5. Internal pudendal artery. Usually terminal branch. Supplies mostly external genital organs and
perineum. It divides into:
a. Inferior rectal artery
b. Perineal artery
c. Artery to the bulb of vestibule or artery to the bulb of penis
d. Urethral artery
e. Deep artery of penis/deep artery of clitoris
f. Dorsal artery of penis or dorsal artery of clitoris
6. Obturator artery (parietal). It pasess through the obturator canal (enters along with the obturator
nerve) and supplies the hip adductor muscles. The origin is variable (can also arise from the internal
pudendal artery, external iliac artery, inferior epigastric artery).
7. Inferior gluteal artery (parietal). Usually terminal branch. Usually arises from the terminal part of
anterior trunk and leaves the pelvic cavity through inferior part of the grater sciatic foramen. It
supplies the gluteal region and posterior side of the thigh. Branching off in the proximal part of the
anterior trunk is also possible.
1.8.1.2 Branches of the posterior trunk of internal iliac artery
1. Iliolumbar artery. It passes similarly the lumbar arteries and divides into two terminal branches:
a. Lumbar branch
b. Iliac branch
2. Lateral sacral artery. Usually runs on the pelvic surface of the sacral bone. Can pass into the
anterior sacral foramen.
3. Superior gluteal artery. Leaves the pelvic cavity through superior part of the greater sciatic
foramen (above the piriformis), usually between L5 and S1 spinal nerves.

Fig. 1.9. Relations of the obturatory nerves and vessel on the coronal section.

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Fig. 1.10. Branches of the internal iliac artery. Exact artery origins may vary, depending on the particular specimen. (a) – lacuna vasorum –
space for vessels; (b) – suprapiriform (upper) part of major sciatic foramen; (c) – infrapiriform (lower) part of major sciatic foramen; (d) – minor
sciatic foramen; (e) – obturator foramen.

2 Perineum
The perineum is a diamond shaped area represented by the lowest region of the trunk, which is located
between the thighs and the lower part of the buttocks.

2.1 Boundaries of the perineum

The perineum and the pelvic outlet share the same ligamentous and osseous boundaries:

1. Anterior - pubic symphysis

2. Posterior - the coccyx
3. Anterolateral - on each side, the ischiopubic rami and ischial tuberosities
4. Posterolateral - on each side, tuberosities of ischium and the sacrotuberous ligaments
The perineal region is normally divided into an anterior (urogenital) and a posterior (anal) triangle by an
imaginary line which joins the anterior regions of the ischial tuberosities.
1. Urogenital triangle, located in front of the line, contains the genitalia and the terminal region of the
urinary tract.
2. Anal triangle, posterior to the line, contains the anal canal and anus.

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Fig. 2.1. The perineal region.

Perineum has a floor composed of skin and fascia. Perineum roof is formed by the pelvic diaphragm.

2.2 Pelvic diaphragm

The funnel-shaped pelvic diaphragm lies between the pelvic cavity (above) and the perineum.

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Fig. 2.2. Coronal section through the posterior part of the pelvis.

2.2.1 Structure of the pelvic diaphragm

The pelvic diaphragm is formed by two muscles, levator ani and coccygeus (also called ischiococcygeus).

1. Levator ani muscle, which can be subdivided into three parts (from bottom to top):
a. Puborectalis is U-shaped muscular sling around the anorectal junction, below the coccyx.
Some fibers of this muscle constitute the levator prostatae and pubovaginalis. Origins:
posterior surface of bodies of pubic bones; Insertion: N/A (it forms the sling posterior to
rectum).
b. Pubococcygeus, which is the most substantial part of the levator ani muscle. Origin:
Posterior surface of bodies of pubic bones. Insertion: coccyx and anococcygeal ligament,
also vagina/prostate.
c. Iliococcygeus, which is thinner than pubococcygeus. Arises laterally on each side of the
tendinous arch of the obturator fascia, passes medially and posteriorly, and attaches to the
coccyx and to the anococcygeal ligament. Origin: Tendinous arch of interal obturator fascia.
Insertion: coccyx and anococcygeal ligament.
Action: Stabilization of the abdominal and pelvic cavity contents. Resistance against intra-
abdominal pressure. Opening/closing of the levator hiatus.
Blood supply: Inferior gluteal artery, inferior vesical artery, internal pudendal artery.
Nerve supply: Nerve to levator ani (S4). Pubococcygeous only: pudendal nerve (inferior rectal and
perineal branches).
2. Coccygeus muscle is situated against the posterior part of the iliococcygeus muscle and it forms
the smaller part of the pelvic diaphragm. Origin: Ischial spine. Insertion: Inferior end of sacrum,
coccyx. Action: Stabilization of the abdominal and pelvic cavity contents. Coccyx flexion. Blood
supply: Inferior gluteal artery, inferior vesical artery, internal pudendal artery. Nerve supply:
Anterior rami of S4-S5.

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Fig. 2.3. The pelvic diaphragm.

The pelvic diaphragm is an elastic sling, which is formed by the combined musculature of the levator ani
muscles (puborectalis, pubococcygeus and iliococcygeus muscles) with the coccygeus muscle. The abrupt
transition from rectum to anus is represented by the fine line where the puborectalis muscle encircles the
rectum. The terminal region of the anal canal is surrounded by voluntary (under human control) muscles
known as the external anal sphincter.
The external anal sphincter consists of a superficial and a deep portion. The fusiform superficial sphincter
surrounds the terminal part of the involuntary internal anal sphincter. Anteriorly, it is attached to the
perineal body and bulbospongiosus muscle, while posteriorly it is firmly anchored to the coccyx. The deep
portion of the external anal sphincter is circular in shape and gains its support

by fusing with the levator ani muscle superiorly. In the absence of defecation and/or passage of flatus, the
anal opening is kept in a closed position by the action of the voluntary anal sphincters.
The pelvic diaphragm constitutes the pelvic floor and supports pelvic viscera. Acting together with the
muscles of the abdominal wall, the levator ani muscle and coccygeus muscle compress the abdominal and
pelvic contents.

2.2.2 Fascia enclosing the pelvic diaphragm

The pelvic diaphragm is enclosed between two layers of the fascia:
1. Superior fascia of the pelvic diaphragm, which covers superior surface of the pelvic diaphragm,
continues laterally as the pelvic parietal fascia, a continuation of the internal abdominal fascia,
transversal fascia and the obturatory fascia.

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 2. Inferior fascia of the pelvic diaphragm, covers the inferior surface of the levator ani muscle, and the
medial wall of the ischioanal fossa.

2.3 Urogenital diaphragm

The urogenital diaphragm - U.G., is a three layer structure (fascia, muscle, fascia) filling the triangular area
bordered by the ischiopubic rami. The U.G. diaphragm is traversed by the membranous urethra in the male
and by the urethra and vagina in the female.

2.3.1 The base of the urogenital diaphragm

The base, the free-border of the triangle, is formed by the fusion of two fascia layers:
1. Posterior region of the inferior fascia of the U.G. diaphragm - perineal membrane,, is a relatively
thick fascia, and it is derived from the muscles it encloses (deep transverse perinei muscles and the
sphincter urethrae muscle). Previously it was noted that this layer also forms the roof of the
superficial perineal pouch (space). This membrane is pierced by the urethra and ducts of the
bulbourethral glands in the male and by the urethra and vagina in the female. Additional passages
are encountered for the nerves and vessels subserving structures of the superficial perineal pouch
located external to this membrane.
2. Posterior border of the superior fascia of the U.G. diaphragm, is derived from the endopelvic fascia,
perhaps from its continuity with the fascia of the obturator internus muscle. The superior fascia
forms the floor of the anterior recess of the ischioanal fossa. This fascial layer and the extent of the
fatty layer within the anterior recess was probed by digital examination in a previous dissection
(see ischioanal fossa, below).

The posterior free-border of the U.G. diaphragm corresponds to the imaginary line interconnecting the
ischial tuberosities to split the perineum into its two triangles. The apex of the triangle does not reach the
pubic symphysis. Instead, the union of the anterior region of the two fascial layers (inferior and superior
fascia of the U.G. diaphragm) forms the transverse perineal ligament.

2.3.2 Muscular layer of the urogenital diaphragm

The muscular layer, intermediate in position, is formed by skeletal muscles:
1. Paired deep transverse perineus muscles, which are attached to the medial surfaces of the ischial
rami and pass transversely into the perineal body.
2. Sphincter urethrae muscle (male) or the urethrovaginal sphincter muscle (in female). In male, the
latter muscle covers the bulbourethral glands located on each side of the membranous urethra.
The ducts of these glands perforate the perineal membrane to drain the seminal fluid (secreted by
the bulbourethral glands) into the bulb of the penil urethra.
In female the urethrovaginal sphincter muscle compress the vagina and urethra.

2.3.3 Deep perineal pouch

The deep perineal pouch or the deep perineal space, is a narrow flat space lined above and below by the
superior and inferior fascial layers of the U.G. diaphragm. The two layers of the fascia are attached laterally
to the pubic arch and join each other at the apex of the triangle and also posteriorly at the base of the
triangle. The narrow interfascial region of the U.G. diaphragm is neither a pouch, nor a space, since it is
packed with the following contents in the anatomy of the male and female (see below):

Structure Male Female

Deep transverse perineus muscle + +
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 Compresses vagina - +
Sphincter urethra muscle + +
Compresses urethra + +
Compresses vagina - +
Urethra (membranous portion) + +
Vagina - +
Bulbourethral glands + -
Drain into urethra/penile + -
Branches of pudendal nerve to:
Muscles of deep perineal pouch + +
Dorsum of penis or clitoris + +
Fig. 2.4. Contents of the deep perineal pouches in the two sexes.

2.3.4 Muscles associated with the external genital organs

1. Superficial transverse perineus, which is covered by the deep (muscular) fascia, is located along the
inferior surface of the posterior "free-border" of the urogenital diaphragm. The muscle extends
between the ischial tuberosities and the perineal body.
2. Ischiocavernosus (paired muscle), surrounds the crura of the penis/clitoris. These erectile bodies
are attached along the ischiopubic rami and are superficially covered, in sequence, by
ischiocavernosus muscle and its fascia (also known as the deep fascia or muscular fascia).
3. Bulbospongiosus and its fascia cover the bulb of the penis. The unpaired corpus spongiosum penis
is traversed by the spongy portion of the urethra (male only). The superficial aspect of the bulb is
covered by the paired bulbospongiosus muscles, which are united along the midline. Superficially, a
fascial layer covers the muscles. The posterior end of the bulb is penetrated by the urethra which
crosses the length of the corpus spongiosum as the spongy urethra to open at the glans penis.

The perineal body, also known as the central tendinous point of the perineum, is a fibromuscular structure
attached to the middle of the posterior border of the urogenital diaphragm. This fibrous thickening is
formed by the fusion of fascia and fibers of the musculature of the urogenital diaphragm (sphincter
urethrae and deep transverse perineal muscle) with muscular fasciculi from the pelvic diaphragm
(pubococcygeus muscle of levator ani muscle) and perineal attachment of the external anal sphincter
muscle. The perineal body has significance in obstetric and gynecological procedures of the perineal area.

2.4 Superficial perineal fascia

After reflecting the skin of the perineum, note that the superficial perineal fascia, like that of the
abdominal wall, consists of a superficial adipose (fatty) layer and a deeper fibrous (membranous) layer. The
fatty layer of this region continues up from the thighs and posteriorly into the ischioanal (ischiorectal) fossa
(the fatty tissue of the anal triangle which is concentrated on the lateral aspect of the anus). Upon reaching
the scrotum and skin of penis, the fatty layer diminishes to a monocellular film, which blends with the
fibrous layer of the superficial perineal fascia. In the lower abdominal and perineal region of the male, the
subcutaneous fibrous layer displays several extensions, fusions and attachments with fascia of surrounding
structures resulting in multiple eponyms attributed to the same (fibrous) layer: superficial abdominal
fascia, superficial fascia around the penis, Darto's fascia/muscle lining the skin of the scrotum, Colle's fascia
over the superficial perineal pouch.
Along the midsagittal plane, the fibrous layer of the subcutaneous perineal fascia attaches along the
septum of the scrotum and to the midline of the fibrous raphe lining the superficial aspect of the
bulbospongiosus muscle. Laterally, it attaches to the ischiopubic rami and posteriorly it blends with the

20
fascial lining of the free border of the urogenital diaphragm. These fascial attachments are often verified
clinically in the perineum of the male by regional entrapment of extravasated body fluids following injuries
of the erectile tissue and/or urethra. The attachments of this fascial layer in the female perineum, differ
only in respect to their medial attachment along the intervening vaginal walls.

2.5 Superficial perineal pouch

The superficial perineal pouch represents a specific region of the urogenital triangle bounded inferiorly by
the fibrous layer of the superficial perineal fascia and superiorly by the perineal membrane (inferior fascia
of the urogenital diaphragm).

Structure Male Female

Central tendinous point of the perineum + +
Superficial transverse perineus muscle + +
Root of the penis/clitoris + +
Bulb of the penis/bulbs of the vestibule + -
Proximal part of the spongy urethra + +
Contents of the scrotum + -
Greater and lesser vestibular glands - +
Branches of internal pudendal vessels & nerves + +
Fig. 2.5. Contents of the superficial perineal pouches in the two sexes.

2.6 Ischioanal fossa

The borders of the ischioanal fossa (ischiorectal fossa) are best observed after splitting the pelvis to study
the blood vessels and nerves associated with the muscle and fasciae of the lateral pelvic walls. The canal is
formed by splitting the inferior margin of the fascia of the obturator

internus muscle along the lateral wall of the fat-filled ischioanal fossa. The pudendal canal courses about 4
to 5 cm above the medial aspect of the ischial tuberosity to conduct the vessels mentioned above, and the
nerve to the posterior aspect of the urogenital (U.G.) diaphragm.

2.6.1 Boundaries of the ischioanal fossa

1. Base is formed by the deep fascia and perineal skin,
2. Anteriorly it continues into the anterior recess of the ischiorectal fossa (superior to the urogenital
diaphragm),
3. Medially: by the inferior fascia of the urogenital diaphragm,
4. Laterally: by the obturatory fascia (contains the pudendal canal (canalis pudendalis) - formed by
Two layers of the obturatory fascia, it contains the internal pudendal artery & vein and pudendal
nerve),
5. Apex is located about 6 cm above the ischial tuberosity.

2.6.2 Contents of the ischioanal fossa

1. Internal pudendal artery, vein, and nerve.
2. Branches of pudendal nerve: inferior rectal nerve, perineal nerve, dorsal nerve of penis/clitoris.
3. Inferior rectal artery and vein
4. Posterior scrotal vessels
5. Lymphatics

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Adipose tissue on both sides of the anal canal permits extension of the anal canal during defecation. It also
supports the levator ani muscle action during balancing the graudally changing presures in the intra- and
extraperitoneal spaces.
Clinical comments: Contents of the ischioanal fossa are prone to lesions or compression.

2.6.3 Arterial supply of the perineum (internal pudendal artery)

The perineum is supplied by the branches of one artery - the internal pudendal artery. The superficial
perineal veins are tributaries of the femoral vein (which drains into the external iliac vein) while the deeper
veins collect into the internal iliac vein (via the prostatic or vesical plexus and the internal pudendal vein).
The internal pudendal artery (I.P.A.), a branch of the internal iliac artery, leaves the cavity of the true
(lesser) pelvis by passing laterally, between the piriformis and coccygeus muscle, to reach the inferior rim
of the greater sciatic foramen. Next, the vessel loops around the external aspect of the ischial spine and
attachment of sacrospinous ligament to enter the lesser sciatic foramen by which it gains access to the
perineal structures. At the posterior aspect of the medial wall of ischial tuberosity, the I.P.A., the
accompanying veins, and the pudendal n. (P.N.), enter the pudendal canal.

2.6.4 Branches of the internal pudendal artery

Branches of the I.P.A. has the same distribution and virtually the same branches as the pudendal nerve.
2.6.4.1 Branches within the pudendal canal
1. Inferior rectal artery passes through the fat of the ischioanal fossa to supply the external anal
sphincter mm. and the skin of the anal region,
2. Perineal artery runs over the superficial transverse perineus muscle and passing between the
bulbospongiosus and ischiocavernosus muscles supplies all three muscles of the superficial perineal
pouch. The artery gives off a posterior scrotal/labial branch, which provides afferent branches to
the posterior wall of scrotum (skin and tunica dartos).
2.6.4.2 Branches in the deep perineal pouch
The I.P.A. reaches the posterior border of the deep perineal pouch where it may stay superficial to the
inferior membrane of the U.G. diaphragm (perineal membrane), or most likely, it passes above the perineal
membrane to enter the deep perineal pouch (D.P.P.). Within the D.P.P. the I.P.A. breaks into its terminal
branches as follows:

1. Branches to musculature of the deep perineal pouch (sphincter urethrae and deep transverse
perineus muscles, in the male; mixture of fibers of sphincter urethrae and vagina in the female).
2. Artery to the bulb of penis (male)/vestibule (female) gives off a branch to bulbourethral gland
(male), then the parent artery passes through the perineal membrane, enters the bulb (penis or
vestibule) to supply the bulb and posterior segment of the corpus spongiosum penis.
3. Urethral artery pierces the membrane to enter the corpus spongiosum, which it follow to the glans
of penis,
4. Deep artery of the penis/clitoris, pierces the membrane to enter the center of each corpus
cavernosus penis/clitoris.
5. Dorsal artery of the penis/clitoris leaves the anterior region of the U.G. diaphragm, passes through
the suspensory ligament of the penis (clitoris) to enter the dorsal aspect of the penis where it runs
deep to Buck's fascia (derived from fascia of bulbospongiosus muscle).

2.7 Innervation of the perineum

The perineum is supplied by the branches of the pudendal nerve. Branches of the pudendal nerve are:
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 1. Inferior rectal nerve - to the external anal sphincter
2. Perineal nerves with its:
a. Deep branch (or motor fibers) to all perineal muscles
b. Posterior scrotal (labial) branches (sensory)
3. Dorsal nerve of the penis/clitoris to erectile tissue and skin.

2.8 Venous drainage of the perineum

Tributaries of the external iliac vein:

1. Superficial dorsal vein of penis/clitoris: single structure, which passes towards the pubic
symphysis, without accompanying arteries and/or nerves, to drain, by splitting into a right and left
branch, into the external pudendal vein (a tributary of the greater saphenous vein or of femoral
vein).
Tributaries of the internal iliac vein:

1. Deep dorsal vein of penis/clitoris - on each side the vein is bordered by a dorsal artery (of penis)
and lateral to the artery, branches of the dorsal nerve of penis/(clitoris. The deep dorsal vein (of
penis/clitoris) does not course through the deep perineal pouch. The vein leaves the penis/clitoris
to pass between the transverse perineal and arcuate pubic ligaments to drain into the prostatic
plexus of veins (male) or vesical plexus of veins (female)
2. Deep vein of penis/clitoris: collects blood from the cavernous tissue before draining into the
internal pudendal vein from which blood passes into the prostatic or vesical venous plexus,
3. Rectal plexus of veins.

2.9 Homology of structures in the male and female perineum

Male perineum Female perineum

Bulbourethral glands (Cowper's) Greater vestibular glands (Bartholin's)
Scrotum Labia majora
Corpus spongiosum Labia minora and the bulb of the vestibule
Penis Clitoris
Urethra (consisting of: prostatic via prostate gland, Urethra
membranous (via UG diaphragm) and spongy (via
corpus spongiosum).

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3 Male itnernal genital organs

Fig. 3.1. Male genital organs.

3.1 Testes
The testes are paired, ovoid in shape, male reproductive organs, which are suspended by the spermatic
cords in the scrotum. The testis (testis) is covered by the tunica albuginea. The testes are also covered by
visceral and parietal layers of the tunica vaginalis. The visceral layer of the tunica vaginalis covers tunica
albuginea testis and epididymis.
A testis has:

1. Two surfaces - medial and lateral

2. Two margins - anterior and posterior
3. Two ends - superior and inferior

The septa testis divides the stroma testis into lobules. The stroma testis is composed of the seminiferous
tubules. The main function of the testes is production of the male gamete cells and male sex hormones
called androgens.

3.1.1 Descent of the testes

The testes enter the inguinal canal after birth and descend through the canal into the scrotum. Normally
the stalk of the processus vaginalis obliterates after birth and one part surrounds the testis. This part is
called the tunica vaginalis.

3.2 Epididymis
The epididymis is a structure located on the superior and posterolateral surfaces of the testis (comma-
shaped).
It is composed of:
1. Head (superior part) - which is composed of the lobules of the epididymis

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 2. Body - contains the efferent ductules
3. Tail - continuous as the ductus deferens

3.3 Ductus deferens

The ductus deferens is a muscular tube which conveys the sperm cells from the tail of the epididymis (of
testes) to the point of union with the ducts of the seminal vesicles. Both, the ductus deferens and
excretory duct form the ejaculatory duct (ductus ejaculatorius). Along its ascent (40-45 cm), each ductus
deferens passes through the spermatic cord and inguinal canal to enter the cavity of the lesser (true)
pelvis.

The ductus deferens can be divided into four parts:

1. Testicular part: accompanies epididymis
2. Portion in the spermatic cord: ascends in the spermatic cord,
3. Inguinal part: passes through the inguinal canal,
4. Pelvic part: passes along the lateral wall of the pelvis and turns into the urinary bladder.

Near the bladder the ductus deferens enlarges and forms the ampulla of the ductus deferens. In cross
sections, this retroperitoneal tube passes from lateral to medial over the ureter to reach the posterior
aspect of the bladder. (The mnemonic of this relation is: bridge [ductus] over water [ureter]). The ureters
descend medially and parallel to the saccules of the seminal vesicles.

3.4 Arterial supply of the testis, epididymis and ductus deferens

1. Testicular artery from the abdominal aorta,
2. Artery of ductus deferens from the internal iliac artery or the umbilical artery,
3. Cremasteric artery from the inferior epigastric artery.

3.5 Venous drainage of the testis, epididymis and ductus deferens

1. Pampiniform plexus
2. Right and left testicular veins which drain into the inferior vena cava and left renal vein.

3.6 Lymphatic drainage of the testis, epididymis and ductus deferens

The lymph from the testis and epididymis drains into the superficial inguinal lymphatic nodes.

3.7 Innervation of the testis, epididymis and ductus deferens

Sympathetic fibers from the testicular plexus (from the celiac plexus) and the parasympathetic from CN X
(vagus nerve).

3.8 Spermatic cord

The spermatic cord begins at the deep inguinal ring, runs through the inguinal canal, and ends at the
posterior border of the testis.

Contents of the spermatic cord:

1. Ductus deferens
2. Testicular artery
3. Artery of the ductus deferens
4. Cremasteric artery
5. Pampiniform plexus
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 6. Genital branch of the genitofemoral nerve
7. Sympathetic and parasympathetic fibres of the ductus deferens
8. Associated lymph vessels

4 Male external genital organs

4.1 Scrotum
The scrotum consists of a few layers, which are presented below in order from the outermost to the
innermost one:

1. Skin
2. External spermatic fascia, which contains the dartos muscle (tunica dartos), is the continuation of
the cutaneous fascia of the anterior abdominal wall; the superficial fascia divides the scrotum into
two halves: the left and right half, it is indicated by the scrotal raphe.
3. Cremasteric fascia is the continuation of the superficial fascia of the anterior abdominal wall
4. Cremaster muscle is the continuation of the the internal oblique and transverse muscle
aponeurosis
5. Internal spermatic fascia is a continuation of the abdominal transversal fascia

4.1.1 Arterial supply of the scrotum

1. Anterior scrotal branches from the external pudendal arteries,
2. Posterior scrotal branches from the internal pudendal artery. Veins correspond to the arteries.

4.1.2 Innervation of the scrotum

1. Genitofemoral nerve supplies the dartos muscle and the cremaster muscle,
2. Anterior scrotal nerves from the ilioinguinal nerve,
3. Posterior scrotal nerves from the pudendal nerve.

4.2 Penis
The penis (penis) is a male organ of copulation (homologous with the clitoris in the female), and is the
common way out for urine and semen.
The penis can be divided into portions:

1. Root of the penis

2. Body of the penis
3. Glans penis

4.2.1 Root of penis

The root of the penis begins near the inferior region of the pubic symphysis where the three tubes
separate into the left and right cavernous body of penis (corpus cavernosum penis) and the spongious
body of penis (corpus spongiosum penis). The separation of the two corpora cavernosa forms the crura
(lat. pl. of crus, a leg) of the penis. The left and right crus is covered by the corresponding ischiocavernosus
muscle (musculus ischiocavernosus) which, in turn, is superficially lined by the muscular fascia.
The root portion of corpus spongiosum is slightly enlarged to form the bulb of the penis (bulbus penis).
Located between the corpora cavernosa, the bulb is firmly attached to the perineal membrane (inferior
fascia of the urogenital diaphragm). The corpus spongiosum contains the spongy urethra (pars spongiosa
urethrae).

26
Fig. 4.1. Inferior aspect of the male perineum.

4.2.2 Body of penis

The body of the penis has no muscles and consists of the corpora cavernosa and the corpus spongiosum.
The root and body of the penis are composed of the cavernous erectile tissue.

4.2.3 Glans of penis

The glans of penis is located distally, it is an expanded part of the corpus spongiosum, and enters there the
external orifice of the urethra (near a tip of the glans). There, on the glans is the highest concentration of
the sensory nerve endings in comparison with the rest of the penis.

4.2.4 Arterial supply of the penis

Arteries, which supply the penis are branches from the internal pudendal artery (arteria pudenda interna):
1. Dorsal arteries of the penis pass on both sides of the dorsal vein
2. Deep arteries of the penis pierce the crura and pass within the corpora cavernosa; they can be
observed in a cross section of the cavernous bodies
3. Artery of the bulb
4. Artery of the urethrae

4.2.5 Venous drainage of the penis

1. Unpaired deep dorsal vein of the penis is located deep to the deep fascia of the penis (Buck's
fascia). On its lateral aspects the vein is accompanied by the left and right dorsal artery and nerve
(of the penis). The deep dorsal vein receives blood from the cavernosus spaces and enters the
lesser pelvis by passing between the arcuate pubic ligament (on the inferior aspect of the pubic

27
 symphysis) and the transverse perineal ligament (on the anterior region of the urogenital
diaphragm). It drains into the prostatic plexus of veins (prostatic venous plexus).
2. Paired superficial dorsal veins drain blood from the superficial coverings of the penis. These veins
return blood into the external pudendal veins and next into the femoral veins.
3. Paired deep veins of the penis, which are located inside the corpora cavernosa, return blood into
the internal pudendal vein.

4.2.6 Lymphatic drainage of the penis

1. Almost all lymph (except the glans penis) is returned into the superficial inguinal lymph nodes.
2. The lymph from glans penis is returned to the deep inguinal lymph nodes.

5 Accessory glands in the male reproductive system

5.1 Prostate (prostatic gland)
The prostate (prostata) is the largest accessory gland, and is located in the true pelvic cavity at the neck of
the urinary bladder. Here it surrounds the first 4 cm of the male (prostatic) urethra. The normal prostate
resembles a 20 – 30 g "buckeye nut", which measures about 4 cm at the base, 2 cm in its anterior to
posterior length and 3 cm in height.
The prostate has:
1. Base - is penetrated by the urethra and related to the caudal region of the urinary bladder
2. Apex - the inferior region of the glans, rests on the superior (deep) layer of the urogenital
diaphragm,
3. Four surfaces:
a. Anterior surface - is convex, it extends between apex and base
b. Posterior surface - triangular in shape, it is in contact with the ampulla of the rectum and
can be easily palpated by examining with a finger in the rectum (per rectum examination)
c. two lateral surfaces
The prostate is enclosed in the fibrous capsule (true capsule), and also by outer capsule, which is the
sheath from the pelvic fascia. Between them the prostatic venous plexus is situated. The alkaline secretion
produced by the prostatic glandular tissue maintains the integrity of the sperm cells and their mobility. It is
transported by the prostatic ductules and ducts (about 30 in number), which enter into the prostatic sinus
on both sides of the posterior wall of the urethra.

5.1.1 Lobes of the prostate

Usually the prostate is divided into three lobes:
1. Two lateral lobes - between them, on the posterior surface, a groove is marked in the midline plane
by the ejaculatory ducts
2. Middle lobe is located between the ejaculatory ducts and the urethra, which are situated
posteriorly to the uvula of the urinary bladder
The clinicians often divide the gland into five lobes which relate to the urethra:
1. Anterior lobe, in front of the urethra
2. Posterior lobe, behind the urethra, inferior to the entrance of the ejaculatory ducts
3. Median lobe, located posteriorly to the urethra and above the ejaculatory ducts

28
 4. Two lateral lobes unite the anterior and posterior lobes, and are penetrated by the ejaculatory
ducts (union of ductus deferens with the duct of the seminal vesicle)

5.1.2 Topographical relations of the prostate

The prostate is located in the true pelvis in the infraperitoneal space.
1. Anteriorly - is located the pubic symphysis
2. Posteriorly - the rectum
3. Superiorly - the urinary bladder
4. Inferiorly - it is supported by the urogenital diaphragm
5. Laterally - the levator ani muscle

Fig. 5.1. Midsagittal section through the male pelvis.

29
Fig. 5.2. Localization of the prostatic gland on the midsagittal section.

5.1.3 Supporting components of the prostate

1. rectovesical ligament - extends between the rectum and the urinary bladder
2. puboprostatic ligament - between the pubic symphysis and the prostate
3. the urogenital diahragm
4. the urethra - stabilizes with the urinary bladder and urogenital diaphragm

5.1.4 Arterial supply of the prostate

The prostate is supplied by branches from the internal iliac artery:
1. Inferior vesical artery
2. Middle rectal artery

5.1.5 Venous drainage of the prostate

The prostatic veins form the prostatic venous plexus, which is located outside the true capsule, and drain
mainly into the internal iliac vein. However, the prostatic venous plexus communicates also freely with the
vesical venous plexus.

5.1.6 Lymphatic drainage of the prostate

Most of lymph produced in the prostate is drained into the internal iliac and sacral lymphatic nodes.
Clinical comments: The enlargement of the middle lobe with advancing age often obstructs the flow of
urine. This obstruction can be removed by insertion of a surgical instrument called the rectoscope into
urethra. Sometimes the prostate is surgically removed, and that is called a prostectomy.

5.2 Bulbourethral glands

Two yellowish bulbourethral glands - Cowper's glands are situated posterolaterally to the membranous
urethra in male. The bulbourethral glands are oval in shape (about 0,5-0,8 cm in diameter) have long ducts

30
of the bulbourethral glands (ductus glandulae bulbo-urethralis) about 3.5-4.0 cm in length, which pass
through the urogenital diaphragm, and open into the proximal part of spongy urethra.

5.3 Seminal vesicles

The paired seminal vesicles resemble small bags (5 cm long, 2 cm in width and 1.5 cm thick) filled with
raisins which rest upon the posterior border of the urinary bladder. The alkaline secretion produced by
these glands is added to the seminal fluid - the seminal vesicles do not store sperm. The duct of each
seminal vesicle narrows significantly near the prostate and joins the corresponding ductus deferens to
form one of the two ejaculatory ducts, which enters the lateral lobe of the prostate. The fluid is expelled
into the excretory duct during orgasm, when the seminal vesicles are contracted.

5.3.1 Topographical relations of the seminal vesicles

1. Seminal vesicles lie parallely and laterally to the descending part of the vas deferens,
2. Posterior relations:
a. Upper region of the vesicles is separated from the rectum by the intervention of peritoneal
lining of the rectovesical pouch,
b. Inferiorly, in the absence of this peritoneal pocket, the posterior surfaces of the vesicles are
separated from the rectum by the connective tissue.

Fig. 5.3. Relations of the deferent ducts and the seminal vesicles (fundus of the urinary bladder).

5.3.2 Arterial supply of the seminal vesicles

The arteries, which supply the seminal vesicles come from the inferior vesical arteries, artery of the ductus
deferens and middle rectal artery. Veins, which drain the seminal vesicles are homologous with the
arteries.

5.3.3 Innervation of the seminal vesicles

The seminal vesicles receive sympathetic fibers from the inferior hypogastric plexus and parasympathetic
fibers from the pelvic splanchnic nerves.

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6 Female internal genital organs
6.1 Uterus
The uterus is a thick (2-3 cm), pear shaped muscular female reproductive organ, measuring about 7-8 cm
in length, 4-5 cm in width, which occupies the central region of the true pelvis.
Uterus is divided into four parts:
1. Fundus, superior, rounded part of the uterus or the part located above the entrance of the uterine
tubes. The regions where the entrances of the paired uterine tubes are located are called cornua of
the uterus.
2. Body, the region between fundus and isthmus, superior two thirds of the organ.
3. Isthmus, a 1 cm constricted region between the body and the cervix.
4. Cervix, is a 2 cm long region, half of which penetrates the posterior region of the vagina, which is
called the infravaginal part. In opposition to that, the supravaginal part of cervix is defined as a
region between the isthmus and posterior vaginal wall.
The cavity of the uterus is triangular in shape. The cervical canal appears as a spindle-shaped channel
which narrows, anteriorly at the ostium, and posteriorly at the isthmus. The uterine ostium is a small
aperture at the vaginal end of the cervical canal.

Fig. 6.1. Midsagittal section through the female pelvis.

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6.1.1 Ligaments of the uterus
1. Cardinal ligament or the transverse cervical ligament is important for stabilization of the cervix in
the midline position. It extends from the lateral pelvic wall to the cervix of the uterus and lateral
side of the vagina,
2. Uterosacral ligament - runs posteriorly from sides of the cervix, around sides of the rectum, to the
middle part of the sacrum,
3. Round ligament - passes under the anterior layer of the broad ligament, from the point of the
organ, which is located anteroinferiorly to the entrance of the uterine tube, to the deep inguinal
ring,
4. Broad ligament, double layer fold of the peritoneum - extends from the lateral sides of the uterus
to the floor and lateral walls of the pelvis. It contains the uterine artery, extraperitoneal tissue
(parametrium), ovarian artery and vein, venous plexus. The round ligaments and uterine tubes are
enclosed between layers of the broad ligament. It also gives an attachment for the ovaries as
double-layer mesovarium and for the uterine tubes as mesosalpinx,
5. Suspensory ligaments of the ovary, fold of the peritoneum, which is prolongation of the broad
ligament; it passes from the lateral end of the ovary to the lateral pelvic wall,
6. Vesicouterinal ligament extends from the anterior surface of the cervix to the fundus of the urinary
bladder,
7. Pelvic diaphragm or the pelvic floor consists of all muscles, which form the diaphragm and are
important for supporting the uterus.

Fig. 6.2. Folds of the peritoneum around the female reproductive organs.

33
6.1.2 Topographical relations of the uterus
The uterus has the following relations:
1. Anteriorly the body of uterus relates to the vesicouterine pouch (excavatio vesicouterina) of
peritoneum (peritoneum is reflected from the posterior margin of the superior surface of the
urinary bladder into the fundus of the uterus), which separates the bladder from the uterus. This
region of the bladder also relates to the supra vaginal region of the cervix. The vaginal cervix is
related to the anterior and lateral fornices of the vagina.
2. Posteriorly the body of uterus comes in contact with the peritoneal lining of the rectouterine pouch
(of Douglas), and coils of ileum or sigmoid colon. The peritoneum, which is reflected from the
fundus into the ampulla of the rectum, separates the uterus from the rectum.
3. Laterally, the body of uterus is related to the broad ligament and uterine vessels. The supravaginal
region of the cervix contacts laterally with the descending ureters, which cross inferiorly to the
uterine artery 2 cm from the cervix.
The uterus has a vesical and an intestinal surface. The relations of the uterus vary with the amount of urine
in the bladder and feces in the rectum. Normally, the organ is inclined anteriorly over an empty bladder. In
addition, the uterus displays two angular displacements: an angulation between its body and its cervix
(anteflexion), and a larger angle (90 ° to 110 °) with the vagina (anteversion).

6.1.3 Composition of the wall of the uterus

The wall of the uterus consists of three layers:
1. Outer layer (perimetrium), which is formed by the parietal peritoneum with the connective tissue,
2. Middle layer (myometrium), which is the muscular part of the uterine wall. It is a layer of smooth
muscles, which normally is about 15 mm thin and increases about 100 times in length during
pregnancy
3. Inner layer (endometrium). It is a mucosus coat, which is sloughed off during each menstrual cycle.

6.1.4 Arterial supply of the uterus (uterine artery)

The main artery of the uterus is the uterine artery, which is a branch from the internal iliac artery. It arises
as the third branch from the internal iliac artery and runs medially between layers of the broad ligament.
The uterine artery is divided into three parts:

1. First portion - descends medially and anteriorly.

2. Second portion - passes horizontally, superiorly to the ureter, which crosses that part 2 cm laterally
from the cervix of the uterus. This part gives off a branch, which supplies the cervix of the vagina.
3. Third portion - ascends along lateral side of the body of the uterus and gives off many branches to
the uterus. At the end, it turns laterally just below the entrance of the uterine tube and runs along
the uterine tube to the ovary and anastomoses (unites) with the ovarian artery.

6.1.5 Venous drainage of the uterus

The uterine vein (vena uterina) accompanies adequate artery and drains to the internal iliac vein. The veins
of the uterus form the uterine venous plexus (plexus venosus uterinus), which is located on each side of
the cervix, and is connected freely with the rectal, vesical and vaginal plexuses. The uterine venous plexus
drains into the internal iliac vien through the uterine vein.

6.1.6 Lymphatic drainage of the uterus

The lymph from the uterus drains in four main directions:
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 1. Lymph from the fundus is drained into the superficial inguinal lymphatic nodes through lymphatic
vessels going with the round ligament
2. Also from the fundus and superior part of the body lymph passes through lymphatic vessels within
the suspensory ligament of the ovary to the lumbal lymphatic nodes
3. Lymph from the inferior part of the body passes to the external iliac lymph nodes,
4. Lymph from the cervix is returned to the sacral and internal iliac lymph nodes.

6.2 Uterine tubes

The paired uterine tubes - Fallopian tubes are located on the left and right upper borders of the broad
ligament and extend laterally from the cornua of the uterus. They end freely in the peritoneal cavity not so
far from the ovaries. The main function of the Fallopian tube is transport of the oocytes from the ovary
(the ova is directed by the ciliated epithelium of the tube to the uterine cavity) and sperm from uterus to
the ampulla, where fertilization usually takes place. The portion of the broad ligament adjacent to the tube
is known as the mesosalpinx (mesosalpinx).

6.2.1 Parts of the uterine tubes

Each (10 cm long, 1 cm width) tube is divided into four parts:
1. Infundibulum, resembling the mouth of a trumpet, represents the expanded lateral projection, by
which the tube communicates with the peritoneal cavity. The rim of this structure has a multitude
of finger-like projections, the fimbriae (20-30 of them), which overlie the ovary,
2. Ampulla, the widest part of the uterine tube, connects the infundibulum to the isthmus,
3. Isthmus, is the narrowest part (2,5 cm long) by which the tube connects to the superolateral
uterine wall,
4. Intramural part is shortest segment, which passes through muscular part of the uteral wall and
terminates at the aperture of the uterine ostium, by which the tube connects to the cavity of
uterus.

Fig. 6.3. Uterine tube

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6.2.2 Arterial supply of the uterine tube
The tubal branches come from two opposite directions. The tubal branch from the uterine artery passes
laterally and anastomises with another tubal branch from the ovarian artery.

6.2.3 Venous drainage of the uterine tube

Veins of the Fallopian tube drain into the uterine (trough the uterine plexus) and ovarian veins.

6.2.4 Lymphatic drainage of the uterine tube

The lymph vessels drain along the ovarian artery and vein into the lumbal lymph nodes.

6.2.5 Innervation of the uterine tube

It receives sympathetic fibres from the coeliac plexus (upper part of the tubal plexus) and from the inferior
hypogastric plexus. The uterine tube receives parasympathetic fibres from the 10th cranial nerve (vagus
nerve) and splanchnic pelvic nerves.

6.3 Ovaries
The ovaries (4 by 2 cm, weighing 2-4 g, oval in shape) are bilateral primary sex female organs, which
occupy the right and left ovarian fossa of the lateral pelvic wall.

Each ovary is covered by cuboidal epithelium, which blends with the peritoneal lining of the mesovarium,
however the oocytes are expelled during ovulation into the peritoneal cavity.
Each ovary has:
1. Anterior margin with hilum of the ovary and mesovarium (mesoovarian border of the ovary),
2. Posterior margin, which is free
3. Inferior end - uteral end
4. Superior end - tubal end
5. Medial surface
6. Lateral surface
Sectioned ovary may be divided into:

1. Outer layer – cortex: contains most of the ovarian follicules.

2. Inner layer – medulla: composed of hormonally functional stroma.
Follicules and corpora lutea may enlarge the ovary to the diameter of 6 cm without being thought to be
pathologically distended.

6.3.1 Ligaments of the ovaries

The ovary is supported by:
1. Mesovarium is an attachment to the posterior border of the broad ligament.
2. Suspensory ligaments of the ovary is an additional attachment, which is the lateral prolongation of
the broad ligament. It provides the ovarian vessels and nerves, which enter to the hilum of the
ovary through the mesovarium.
3. Ligament of the ovary extends from the lateral angle of the uterus to the uteral end of the ovary. It
contains the ovarian branch from the uterine artery.

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6.3.2 Topographical relations of the ovary
The ovary is located within the ovarian fossa of the lateral pelvic wall, which is a shallow depression within
the parietal peritoneum. It is situated below the terminal line of the pelvis and in front to the sacroiliac
joint. The ovarian fossa is bounded by medial umbilcal ligament in front and by the ureter and internal iliac
artery. Superiorly, the ovarian fossa is bounded by the external iliac vessels.

6.3.3 Arterial supply of the ovaries

The ovary is supplied by the ovarian arteries, which arise from the abdominal aorta just below the origin of
the renal arteries, descend to the pelvic brim, cross superiorly the external iliac arteries, next pass within
the suspensory ligaments of the ovary and enter the ovary through the hilum. In addition, the ovary is
supplied by the ovarian branch of the uterine artery. It runs from the uterine artery laterally within the
ligament of the ovary and anastomoses with the ovarian artery.

6.3.4 Venous drainage of the ovary

The ovarian vein leaves the hilum and forms the pampiniform plexus near the ovary, between the layers of
the broad ligament. On both sides the ovarian veins ascend from the pampiniform plexuses. The right
ovarian vein enters to the IVC, but the left ovarian vein (vena ovarica sinistra) joins the left renal vein.

6.3.5 Lymphatic drainage of the ovary

Lymph vessels follow blood vessels through the suspensory ligaments of the ovary and return lymph to the
lumbal lymph nodes.

6.4 Vagina
The vagina is female organ of copulation. It is a distensible muscular tube (7 to 9 cm in length) which
extends between vestibule of the vagina and uterus. The organ consists of two walls which are in contact
except at their upper end. The posterior vaginal wall (12 cm long) is slightly longer than the anterior wall (9
cm long). The vagina descends anteroinferiorly. It pierces the urogenital diaphragm together with the
sphincter uretrae muscle. Assuming the bladder is empty, the posterior portion of the vagina receives the
neck of the uterus at an angle of about 900. This angle increases as the bladder fills and elevates the
fundus of the uterus. In cross sectional anatomy the lower part of the organ resembles an exaggerated
letter H with a long horizontal bar limited by two short parallel lines. Only in the superior end where the
cervix of the uterus enters the vagina, anterior and posterior walls are not in apposition. The vaginal recess
around the cervix is called the fornix.

6.4.1 Topographical relations of the vagina

1. Anteriorly: bladder, terminal parts of the ureters and urethra
2. Posteriorly: recto-vaginal pouch (space), rectum and anal canal
3. Laterally: broad ligament and ureter, levator ani
4. Inferiorly: perineal body, vestibule of the vagina
External orifice of the vagina is sourrounded by the sphincter of the vaginal muscle.

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7 Female external genital organs

Fig. 7.1. Female external genital organs overview

7.1 Mons pubis

The mons pubis is a fatty elevation anterior to the pubic symphysis, which iscovered by pubic hairs.

7.2 Labia majora

The labia majora are two folds of skin, which contain large amount of fatty tissue, situated on each side of
the pudendal cleft. They meet posteriorly at the posterior labial commissure (commissura labiorum
posterior) and anteriorly at the anterior labial commissure (commissura labiorum anterior). They are
embryologically homologous to the male scrotum.

7.3 Labia minora

The labia minora are delicate folds, which are located between the labia majora and they border the
vestibule of the vagina. The labia minora join together superiorly to the clitoris at the prepuce of the
clitoris and posteriorly in young female they meet at the frenulum of the labia minora, which is incised
during labour (episiotomy).

7.4 Vestibule of the vagina

The vestibule of the vagina (vestibulum vaginae) is a space bounded laterally by the labia minora anteriorly
by frenulum of the clitoris (frenulum clitoridis), posteriorly by the frenulum of the labia minora (frenulum
labiorum pudendi). There opens the external urethral orifice, about 2.5 cm below the clitoris and anteriorly
to the vaginal orifice.

The vaginal orifice (ostium vaginae) is closed by the hymen during childhood and may be only a few cm in
diameter in virgins.

7.5 Clitoris
The clitoris (clitoris) is 2 -3 cm long, and is an organ corresponding in female to the penis in male. It is
located posteriorly to the anterior labial comissure and anteriorly to the prepuce of the clitoris.

The clitoris consists of:

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 1. Root
2. Body (composed of by two crura and two corpora cavernosa),
3. Glans
The clitoris enlarges during tactile stimulation, but not significantly.

7.6 Bulbs of the vestibule

Each bulb of the vestibule (2.5 cm) is covered by the corresponding bulbospongiosus muscle and its fascia.
The bulb of the vestibule (bulbus vestibuli) is composed of erectile tissue and is situated on both sides of
the vaginal orifice. The posterior end of the bulb (male) is penetrated by the urethra which crosses the
length of the corpus spongiosum as the spongy urethra to open at the glans penis. The (female) urethra
opens independently between vagina and clitoris without passing through erectile tissue of the corpus
spongiosum. The posterior ends of each bulb of the vestibule are in contact with a small (0.5 cm) nodular
mass formed by the greater vestibular gland. The bulbs of the vestibule and the greater vestibular glands
are located deep to the labia minora.

7.6.1 Greater vestibular glands

The greater vestibular gland is about 0,5 cm in diameter, round in shape and secretes lubricating mucus
into the vestibule of the vagina.

7.6.2 Lesser vestibular glands

The lesser vestibular glands are small glands which also produce mucous and open into the vestibule of
the vagina.

7.7 Arterial supply of the female external genital organs

Arterial supply of the vulva is generally from the two pudendal arteries:
1. External pudendal artery, which gives off the following branches:
a. Dorsal artery of the clitoris
b. Deep artery of the clitoris
c. Posterior labial arteries
d. Artery of the vestibule bulb
2. Internal pudendal artery
a. Anterior labial arteries

7.8 Venous drainage of the female external genital organs

All the veins from the vulva drain into the internal pudendal vein (vena pudenda interna) and next into the
internal iliac vein except two external pudendal veins (venae pudendae externae) – they receive blood
from the anterior labial veins and return blood to the femoral vein.

7.9 Lymphatic drainage of the female external genital organs

Most of lymph vessels drain into the superficial inguinal lymph nodes and deep inguinal lymph nodes.

7.10 Innervation of the female external genital organs

The nerves of the vulva are branches from the ilioinguinal nerve (nervus ilioinguinalis), the genital branch
of the genitofemoral nerve (ramus genitalis nervi genitofemoralis) and pudendal nerve (nervus pudendus).

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