SURFACE & SECTIONAL ANATOMY

- Display of CT images reflects the differences among four basic densities: air (black),
water (dark/gray), fat/blood (gray/light), and bone/metal (white)

Nuclear Medicine Imaging: (glucose uptake)  Fluorodeoxyglucose (FDG))

- uses radioisotopes
- physiology (function)  specifically metastatic disease
- Bone and liver metastases are localized with nuclear medicine scans
- increased uptake, the dark spots  high activity areas that correspond to pathologic
changes
- Gallium scans localize areas of inflammation and tumor activity in patients with
lymphoma
- useful in monitoring changes in tumor size.
- short-lived radioisotopes such as carbon-11, nitrogen-13, fluorine-18, and oxygen-15
- emits positively charged electrons called positrons
- release of gamma rays
- detect blood flow through organs such as the brain and heart, diagnose coronary artery
disease
- identify the extent of stroke or heart attack damage

Magnetic Resonance Imaging

- magnetic properties of the hydrogen nuclei
- tiny magnets spinning in random directions.
- strong uniform magnetic energy is applied to small magnetic fields that lie parallel to the
direction of the external magnet.
- radio waves cause the nuclei to send out a weak radio signal that is detected and
reworked into a planar image of the body
- provides information about chemicals in an organ or tissue.
- Noninvasive
- fused with CT scans
- does not use ionizing radiation
- MRI suite requires the identification of zoned safety areas.
- maintaining an area that is ferrous free (no iron) because the strength of the magnet can
cause those items to forcefully fly into the bore of the unit  All items must be
nonmagnetic

Ultrasound
- high-frequency sound waves that are not heard by the human ear
- waves travel forward and continue to move until they make contact with an object &
sound bounces back
- transducer, a handheld instrument, generates high-frequency sound waves & picks up
the returning sound waves
- resultant image is processed onto a screen and is called a sonogram
 - Ultrasound offers no exposure to ionizing radiation + non-invasive and painless +
requires no contrast media

BODY CAVITIES
- spaces within the body that contain internal organs are called body cavities
- two main cavities
o 1) posterior or dorsal cavities
 A) the spinal or vertebral cavity, protected by the vertebrae, which
contains the spinal cord
 B) the cranial cavity which contains the brain.
o 2) anterior or ventral cavities

LYMPHATIC SYSTEM
- When there’s a high chance of the LN being involved: the supraclavicular fossa (SCF) is
commonly treated even without clinical evidence of tumor present (prophylactic
treatment) because the lymphatic drainage of the head and neck eventually drains to
that area
- three main functions:
o 1) lymphatic vessels drain tissue spaces of interstitial fluid that escapes from
blood capillaries and loose connective tissues, filters it, and returns it to the
bloodstream, maintaining the overall fluid levels in the body  draining and
transporting interstitial fluid is the most important system role.
o 2) lymphatic system absorbs fats and transports them to the bloodstream.
 o 3) body’s defense and immunity  lymphocytes and macrophages protect the
body by recognizing and responding to the foreign matter

LYMPHATIC VESSELS
- Lymph is excessive tissue fluid that consists mostly of water and plasma proteins from
capillaries
- Lymphedema, also known as lymphatic obstruction, is a condition of localized fluid
retention caused by a compromised lymphatic system  a problem in the field of
radiation  the arm swells
- Lymphedema can be controlled with compression bandages and therapeutic exercises
- technique known as the sentinel node biopsy reducing the risk of lymphedema
- larger vessels follow veins and arteries and eventually empty into one of two ducts in
the upper thorax—the thoracic duct or the right lymphatic duct— which then flow into
the subclavian veins.
- Fluid movement in the lymphatic system depends on hydrostatic and osmotic pressures

LYMPH NODES

- A lymph node contains both afferent and efferent lymphatic vessels.

o Afferent lymphatic vessels enter the lymph node at several points along the
convex surface  one-way valves that open into the node, bringing the lymph
into it.
o efferent lymphatic vessels  smaller in diameter  valves open away from the
node, facilitating one-way flow.
- Edema can occur when excessive foreign bodies, lymph, and debris are engulfed in the
node  when a person has a cold or the flu
- subdigastric nodes, located in the neck just below the angle of the mandible, become
swollen and tender because of the heightened phagocytic activity
- This condition is commonly seen after mastectomy.
- Arm is often swollen because of the altered natural lymphatic pathways after the
operation

LYMPHATIC ORGANS
- spleen is the largest mass of lymphatic tissue
- B cells: develop into antibody-producing plasma cells
- Thymus: located along the trachea superior to the heart and posterior to the sternum in
the upper thorax
o becomes smaller as we enter adulthood  if it’s large then it indicates a problem
with the immune system  “immunodifiency syndrome”
- T lymphocytes can mature.
- located at the junction of the oral cavity and pharynx  lymphoid tissue protect against
foreign body infiltration by producing lymphocytes
SKULL, VERTEBRAL COLUMN, & THORAX
SKULL
- 22 bones: 8 true cranial bones and 14 considered facial bones.
- consists of two maxillary bones, two zygomatic bones, two nasal bones, two lacrimal
bones, two palatine bones, two inferior conchae, one vomer, and one mandible.
SUTURES
- four prominent sutures in the skull, or fibrous joint
- 1) coronal suture lies between the frontal bone and the two parietal bones.
o begins at the bregma and ends at the temporal bone.
- 2) sagittal suture lies between the two parietal bones and runs from the bregma to the
lambda
- 3) e lambdoidal suture is in the posterior portion of the skull and lies between the
parietal and occipital bones
- 4) squamosal sutures, one on each side of the skull, are located near the ears and lie
between the parietal and temporal bones
PARANASAL SINUSES
- air spaces lined by mucous membranes
- 1) maxillary sinus is a pyramid-shaped cavity = largest of the paranasal sinuses
- 2) frontal sinus lies in the frontal bone above the orbit.
- 3) sphenoid sinus lies posterior and superior to the nasopharynx, enclosed in the body
of the sphenoid bone at the level of the zygomatic arch
o Superiorly the sinus is related to the sella turcica superior to the external
auditory meatus [EAM]) and the pituitary.
- 4) ethmoid sinus is bilateral but consists of a honeycomb of air cells that lie between the
middle wall of the orbit and the upper lateral wall of the nose.
VERTEBRAL COLUMN
- extends from the skull to the pelvis
- 33 bones in the adult vertebral column
- 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae
- sacrum supports the rest of the vertebral column
- vertebrae are separated by radiolucent fibrocartilage called intervertebral disks
- lumbar spine, the height of the disk increases
- protects the spinal cord and provides points of aachment for the skull, thorax, and
extremities.

VERTEBRAL CHARACTERISTICS
- 31 pairs of spinal nerves that run along the spinal cord
o nerves run through the intervertebral and sacral foramina
o nerves terminate at an area termed the cauda equina (horse’s tail)  at the end
of the vertebrae
- first two vertebrae, C1 and C2, are atypical from all others
o C1, the atlas, serves the specialized function of supporting the skull
o C2, the axis, has an odontoid process
- prominent spinous process that can be palpated at the base of the neck.

VERTEBRAL BODY CURVATURES

- cervical curve (C1 to T2)  convex anteriorly
- thoracic curve (T2 to T12)  concave anteriorly
- lumbar curve ( T12 to the anterior surface of L5)  convex forward
- pelvic curve  sacrum and coccyx  concave anteriorly
- Kyphosis: is an excessive curvature of the vertebral column that is convex posteriorly.
o degenerative vertebral changes
- Scoliosis: abnormal lateral curvature of the vertebral column with excessive right or left
curvature in the thoracic region.
 o Wilm’s tumour
- Lordosis: excessive convexity of the lumbar curve of the spine
- Spondylolisthesis: one of the spine’s vertebrae (bones) slips forward over the vertebra
beneath it
o occurs most often in the lumbar spine (low back).
THORAX
- bony cage formed by the sternum, costal cartilage, ribs, and thoracic vertebrae
- protects the organs in the thoracic cavity and upper abdomen
- provides support for the pectoral girdle and upper extremities.

STERNUM & RIBS

- sternum a.k.a breastbone,
- three parts: the manubrium, body, the middle and largest portion and xiphoid process
o manubrium has a depression called the suprasternal notch (SSN) at level of T2
o manubrium also articulates with the first two ribs.
o junction of the manubrium and the body form the sternal angle  angle of Louis
 at the level of T4.
o body of the sternum articulates with the 2nd through 10th ribs
 vertebrosternal ribs => Of the 12 pairs of ribs, the superior 7 pairs are
considered true ribs
 vertebrochondral ribs (false ribs) => next three pairs join with the
vertebrae posteriorly and anteriorly with the cartilage of the immediately
anterior rib
 floating ribs => (last) pairs articulate only with the vertebrae and do not
connect with the sternum in any way
ANATOMY OF THE H&N
BONY LANDMARKS: ANTERIOR & LATERAL SKULL
- frontal bone = maximal convexity on the forehead and articulates with the frontal
process of the maxillary bone
o protects the lacrimal duct and glands.
- glabella = slight elevation directly between the two orbits in the frontal bone, just above
the base of the nose.
o SOM = used to delineate the inferior border of whole brain fields (along with the
tragus and mastoid tip)
- maxilla = bone between the ala of the nose and the prominence of the cheek
o houses the largest of the paranasal sinuses.
- zygomatic bone = forms part of the lateral aspect of the orbit and the prominence of the
cheek.
o articulation between the frontal process of the zygomatic bone and the
zygomatic process of the frontal bone  lateral orbital margin (LOM).
- mastoid process = extension of the mastoid portion of the temporal bone at the level of
the earlobe
o used to delineate the posterior point of the inferior whole brain border
- external occipital protuberance (EOP; or inion) = prominence of the occipital bone of the
skull.
LANDMARKS AROUND THE EYE
- SOM, LOM, medial orbital margin, inner canthus (IC), outer canthus (OC), punctum
lacrimae

LANDMARKS AROUND THE NOSE

- Lateral ala nasi, nasion, glabella
LANDMARKS AROUND THE MOUTH
- Commissure of the mouth, mucocutaneous junction, columella

LANMARKS AROUND THE EAR

- Auricle of pinna, lobule or earlobe, anterior tragus, tragal notch
LANDMARKS AROUND THE NECK
- superiorly by the EOP and laterally by the mastoid processes
PHARYNX
- pharynx is a membranous tube that extends from the base of the skull to the esophagus.
- It connects the nasal and oral cavities with the larynx and esophagus
- divided into the nasopharynx, oropharynx, and laryngopharynx (hypopharynx)
- SET up: S, spinal cord; E, esophagus; and T, trachea.
- nasopharynx or epipharynx = communicates with the nasal cavity and provides a
passageway for air during breathing
- oropharynx or mesopharynx = opens behind the soft palate into the nasopharynx and
functions as a passageway for food moving down from the mouth and for air moving in
and out of the nasal cavity.
- laryngopharynx, or hypopharynx= located inferior to the oropharynx and opens into the
larynx and esophagus. This structure continues throughout the thorax as the esophagus.

LARYNX
- lower portion of the pharynx above it and to the trachea below it
- extends from the tip of the epiglottis at the level of the junction of C3 and C4 to the
lower portion of the cricoid cartilage at the level of the C6 vertebra
- subdivided into three anatomic regions: the supraglottis, glottis, and subglottis
- enlargement in the airway at the top of the trachea and below the pharynx
- passageway for air moving in and out of the trachea and functions to prevent foreign
objects from entering the trachea.
- inferior margin of the sixth cervical vertebra
- larynx continues as the trachea.
- thyroid cartilage forms a midline prominence, the laryngeal prominence or Adam’s apple

NASAL & ORAL CAVITIES

- opens to the external environment through the nostril
- nostrils are continuous with the nasopharynx
- lined with a ciliated mucous membrane
- opens posteriorly into the oropharynx
- houses the soft palate, hard palate, uvula, anterior tongue, and floor of the mouth.
SURFACE ANATOMY OF THE NECK
- most commonly used landmarks of the neck are: Skin profile, Sternocleidomastoid
muscle, Clavicle, Thyroid notch, Mastoid tip, EOP, Spinous processes

LYMPHATIC DRAINAGE OF THE H&N

- lymphatic drainage of the head and neck is through deep and superficial lymphatic
channels
- Enlarged cervical lymph nodes are the most common adenopathy
- site of metastatic disease from the head and neck, lungs, breast, or of primary
lymphoreticular disease such as Hodgkin disease.
- occipital lymph nodes, retroauricular lymph nodes (drain the posterior temporo-occipital
region of the scalp, auricle, and EAM),
- deep parotid lymph nodes (drain the nose, eyelid, frontotemporal scalp, EAM, and
palate)
- submaxillary lymph nodes are facial nodes (drain the eyelids, nose, and cheek and
supply efferent flow to the submandibular nodes)
- submandibular lymph nodes lie on the outer surface of the mandible (drain the scalp,
nose, cheek, floor of the mouth, anterior two-thirds of the tongue, gums, teeth, lips, and
frontal, ethmoid, and maxillary sinuses)
- retropharyngeal lymph nodes
o commonly involved in nasopharyngeal tumors
o included in the treatment fields.
- submental lymph nodes
o in the submental triangle of the digastric muscles
o efferent drainage to the submandibular nodes.
- superficial cervical lymph nodes (in front of the larynx, trachea, and thyroid gland)
- deep cervical lymph nodes (chain of 20 to 30 nodes)
o around the internal jugular chain along the sternocleidomastoid muscle
o cervical lymph nodes are typically included in the treatment fields of most head
and neck cancers that spread through the lymphatics
- jugulodigastric lymph node (a.k.a subdigastric node)
o drains the tonsils and the tongue
o juguloomohyoid lymph node (lies in the omohyoid tendon)
o When these two nodes are enlarged, carcinoma of the tongue may be indicated,
because enlarged neck nodes may be the only sign of the disease
- jugular trunk drains into the thoracic or right lymphatic duct
ANATOMY OF THE THORAX & BREAST
- thorax extends from the clavicles superiorly to the costal margin inferiorly.

ANTERIOR THORACIC LANDMARKS

- supraclavicular lymph nodes are located superior to the clavicles  treated
prophylactically in head and neck and lung cancers
- brachial plexus, a network of nerves located at the medial section of the clavicle
- (Pancoast) tumors of the lung
- musculature of the anterior chest wall: pectoralis major, pectoralis minor, and deltoid

THE BREAST & ITS LANDMARKS

- female breasts lie between the second rib superiorly and the sixth rib inferiorly
- medial border  lateral aspect of the sternum
- upper outer portion, called the tail of Spence, extends into the axilla
- upper limits of tangential treatment fields are typically high near the SSN to include the
entire breast and tail of Spence when the SCF is not treated.
- Most tumors are located in the upper outer quadrant of the breast
- Tumor location is important in associating the tumor spread patterns.
o tumor is located in an inner quadrant, the medially located nodes, such as the
internal mammary nodes
o tumor is located in an outer quadrant, the axillary nodes
- tumor location and extension dictate field parameters.
- e inframammary sulcus, the inferior point of breast attachment, varies from person to
person  females with large breasts, the breast overhangs this point of attachment and
the breast can bolus itself in these cases.

POSTERIOR THORACIC LANDMARKS

- major musculature: musculature includes the t
- inferior angle is at the level of T12
- teres major is a band of muscle between the inferior angle of the scapula and the
humerus
- latissimus dorsi is the broad muscle on either side of the back that spans from the iliac
crest of the pelvic bones to the posterior axilla.
- spine of the scapula is located at the level of T3 to T7
- crest of the ilium is located at the level of L4
- subarachnoid space  lumbar punctures are commonly made.

INTERNAL & SECTIONAL ANATOMY OF THE THORAX

- trachea is the part of the airway that begins at the inferior cricoid cartilage at the level of
C6
- bifurcation, called the carina, at the level of T4 to T5 at angle of Louis  bifurcation
forms the beginning of the right and left main bronchi
- diaphragm is the dome-shaped muscle separates the thorax and abdomen  important
in respiration
 o lies between T10 and T11
- esophagus and inferior vena cava pass through the diaphragm at the level of T8 to T9
- descending aorta goes through at the level of T11 to T12
- lungs correspond closely with the pleura
- heart rests directly on the diaphragm in the pericardial cavity, covered anteriorly by the
body of the sternum
- base of the heart lies at the level of T4
- arteries of the thorax: ascending aorta, descending aorta, left common carotid, left
subclavian arteries, superior vena cava is located at the level of T4, inferior vena cava
(lies in the right cardiodiaphragmatic angle)
LYMPHATICS OF THE BREAST & THORAX
- The lymph nodes of the thorax are divided into nodes that drain the thoracic wall and
breast and those that drain the thoracic viscera.
BREAST LYMPHATICS
- Three lymphatic pathways of the breast: axillary, transpectoral, and internal mammary
pathways
- axillary lymphatic pathway  drain to the axilla (principal pathway)  drain the lateral
half of the breast
o in invasive breast cancers: axillary nodes are commonly biopsied for assessment
of disease spread
- transpectoral lymphatic pathway  provides drainage to the supraclavicular and
infraclavicular fossa nodes.
- internal mammary lymphatic pathway  internal mammary nodes are more commonly
involved with primary breast cancers that are located in the inner breast quadrants
THORACIC LYMPHATICS
- superior mediastinal nodes, tracheal nodes a.k.a paratracheal nodes, inferior
mediastinal nodes, inferior tracheobronchial nodes a.k.a carinal nodes,
bronchopulmonary nodes a.k.a hilar nodes, pulmonary nodes a.k.a hilar nodes,
pulmonary nodes a.k.a intrapulmonary nodes
- right lung, all three lobes drain to the intrapulmonary and hilar nodes  then flow to
the carinal nodes and then to the paratracheal nodes before they reach the
brachiocephalic vein and right lymphatic duct
- left lung, the upper lobe drains to the pulmonary and hilar nodes, carinal nodes, left
superior paratracheal nodes, and then the brachiocephalic vein through the thoracic
duct

ANATOMY OF ABDOMEN & PELVIS

ANTERIOR ABDOMINAL WALL

- anterior abdominal wall is bordered superiorly by the inferior costal margin and
inferiorly by the symphysis pubis, inguinal ligament, anterosuperior iliac spine (ASIS),
and iliac crest
- major muscles that help form the anterior abdominal wall: rectus abdominis, transverse
abdominis, internal oblique, and external oblique.
- xiphoid process at the level of T9  very stable bony landmark & used along with the
SSN to ensure that a patient is lying straight on the treatment couch
o can also be used in conjunction with the symphysis pubis
- umbilicus a.k.a navel or belly button is an inconsistent, mobile landmark at the level of
L4
POSTERIOR ABDOMINAL WALL (TRUNK)
- lower ribs, lumbar spines, PSIS, and iliac crest are palpable
- intercristal line

LANDMARK OF THE ANTERIOR PELVIS

- iliac crest extends from the ASIS to the PSIS. The ASIS is palpable & used in referencing
the location of the femur
- iliac crests are the most superior margin of the ilium
- head of the femur articulates with the hip at the acetabulum
- fibrotic changes can occur and cause painful or limited motion of the joint
- greater trochanter is the only part of the proximal femur that can be palpated
- symphysis pubis  uses these components when setting the anterior border of lateral
prostate fields (the prostate lies immediately posterior to the symphysis pubis
- ischial tuberosities corresponds to the lower region of the buttock.
- use the ischial tuberosities as the inferior border of the anterior and posterior prostate
treatment portals.
- anterior commissure of the labia majora is easily distinguishable in the female  an
important soft tissue landmark from which the upper or lower border pubis is measured.
- base of the penis used as a reference point from which the upper or lower border pubis
is measured in the male
LANDMARKS OF THE POSTERIOR PELVIS
- most commonly used bony surface landmarks of the posterior pelvis: PSISs, the coccyx,
the iliac crests, and the lateral iliac crests
- PSISs are indicated by dimples above and medial to the buttock
- coccyx lies deep with its inferior end approximately 1 cm from the anus.
LOCATION OF NONALIMENTARY ORGANS
- liver is an irregularly shaped organ located in the right hypochondriac region of the
abdomen above the costal margin.
o superior margin of the liver, which bulges into the diaphragm, is at the level of T7
to T8
- gallbladder is located below the lower border of the liver and contacts the anterior
abdominal wall where the right lateral border of the rectus abdominis crosses the ninth
costal cartilage.
o transpyloric plane.
- Spleen located posteriorly at the level of T10 to T11
- often examined surgically in patients with lymphoma to determine disease extension
- Three components, the head, body, and tail, compose the pancreas
o head of the pancreas is located in the C section of the duodenum
o body extends slightly superiorly at the level of L1
o tail of the pancreas passes into the hilum
LOCATION OF THE URINARY TRACT ORGANS
- kidneys lie on the posterior abdominal wall in the retroperitoneal space
- hilum of the right kidney is at the level of L2
- hilum of the left is at the level of L1
- right kidney lies lower than the left because of the presence of the adjacent liver
- Superior and medial to each kidney are the adrenal glands
- Kidneys move 2 cm with respiration
- ureters are tubular structures that transport urine from the kidneys to the urinary
bladder
- anterior to the psoas muscles and enter the pelvis lateral to the sacroiliac (SI) joint.
- neck of the bladder lies posterior to the symphysis pubis and anterior to the rectum.
- superior to the prostate in the male
- urinary bladder is a dose-limiting structure in the treatment of prostatic cancer

LYMPHATICS OF THE ABDOMEN & PELVIS

- lymphatic pathways and nodes of the abdomen  visceral nodes
- three principal groups of nodes of the abdomen: preaortic nodes=> celiac, superior
mesenteric, and inferior mesenteric groups
o celiac nodes = drain the stomach, greater omentum, liver, gallbladder, and spleen
and most of the lymph from the pancreas and duodenum
o superior mesenteric nodes= drain part of the head of the pancreas; a portion of
the duodenum; the entire jejunum, ileum, appendix, cecum, and ascending
colon; and most of the transverse colon
o inferior mesenteric nodes= drain the descending colon, the left side of the
mesentery, the sigmoid colon, and the rectum.
o paraaortic nodes= provide efferent drainage to the cisterna chyli, beginning of
the thoracic duct from T12 to L4
o paraaortics= drain the uterus, ovary, kidneys, and testicles
o common iliac nodes= lie at the bifurcation of the abdominal aorta at the level of
L4
 drain the urinary bladder, prostate, cervix, and vagina.
 breaks up into the external and internal iliac nodes
 external iliac nodes = drain the urinary bladder, prostate, cervix, testes,
vagina, and ovaries
 internal iliac nodes a.k.a hypogastric nodes= drain the vagina, cervix,
prostate, and urinary bladder
o inguinal nodes = more superficial
 drain the vulva, uterus, ovaries, and vagina
 commonly treated with electrons because of their superficial location.