Anatomy Tables - Axilla, Posterior Shoulder, & Arm

Topographical Anatomy of the Thorax

Structure/Space Description/Boundaries Significance
midaxillary line
(TG4-01)
an imaginary vertical line passing through the middle of the axilla used as a surface landmark for descriptive purposes
midclavicular line
(TG4-01)
an imaginary vertical line passing through the midshaft of the clavicle used as a surface landmark for descriptive purposes
deltopectoral triangle
(TG2-12)
a triangle in the upper chest region that is bounded medially by the clavicle, superiorly by the deltoid m., and inferiorly by the pectoralis major m. the deltopectoral triangle is pierced by the cephalic vein on its course from the upper limb to join the axillary vein in the axilla
nipple
(N182, TG2-10)
located superficial to the 4th intercostal space in the male and prepuberal female; areola is dark ring surrounding nipple location of the left nipple may be used to help locate the apex of heart, which is approximately 8 cm from the midline in the left 5th intercostal space; a surface landmark used to place the stethoscope for auscultation of the bicuspid valve
suprasternal notch(N185, TG4-04) the notch located at the superior border of the manubrium of the sternum, between the sternal ends of the clavicles also known as: jugular notch
cubital fossa
(N418, TG2-24)
superior - line between humeral epicondyles, medial - pronator teres, lateral - brachioradialis site for phlebotomy

Osteology

Bone Structure Description Notes
clavicle
(N419, N420, N421, TG2-03A, TG2-03B, Practical)
  an "S" shaped bone located between the sternum and the scapula it articulates medially with the manubrium of the sternum and laterally with the acromion process of the scapula; it forms a strut that supports the upper limb; it is frequently fractured; it is the first bone to begin ossification during development (Latin, clavicula = little key, this term was used to refer to the catch that fastens a window as well as to keys; curved window fasteners resemble the shape of this bone)
  acromial extremity the flattened lateral end of the clavicle it is marked on its inferior surface at the junction of the medial 2/3 and the lateral 1/3 by a roughened area for attachment of the coracoclavicular ligament; it articulates with the coracoid process of the scapula through a syndesmosis; it articulates with the acromion process of the scapula through a synovial joint; due to the shape of the distal clavicle, the acromion process passes inferior to the clavicle in acromioclavicular dislocations (Latin, akron = tip + omos = shoulder, therefore the tip of the shoulder)
rib
(N185, TG4-04)
the bone forming the lateral thoracic wall 12 pairs; several types are described: typical or "true" ribs, "false" ribs, "floating" ribs; all three types of ribs have many features in common: head, neck, tubercle, angle, body, costal groove
sternum
(N185, TG4-04)
the broad flat bone forming the anterior thoracic wall it is formed by three parts: manubrium, body, xiphoid process (Latin, sternum = breastbone, sternere = spread out)
manubrium the superior part of the sternum (Latin, manubrium = handle)
jugular (suprasternal) notch a notch on the superior border of the manubrium it is located between the clavicular notches which articulate with the sternal ends of the clavicles (Latin, jugulum = throat)
clavicular notch a notch on the superolateral border of the manubrium it articulates with the sternal end of the clavicle
sternal angle the junction of the manubrium and body of the sternum it is an anterior projection located at the level of the costal cartilage of rib 2; an important landmark for internal thoracic anatomy
body the middle part of the sternum it articulates with the manubrium superiorly and the xiphoid process inferiorly; laterally it articulates with the costal cartilages of ribs 2-7
xiphoid process the inferior part of the sternum it is variable in size, shape & ossification; it articulates with the body of the sternum superiorly (Greek, xiphos = sword + eidos = appearance)
scapula
(N420, N421, TG2-03A, TG2-03B, Practical1, Practical2)
  the bone of the shoulder the scapula floats in a sea of muscles, so it is difficult to fracture; it articulates with the axial skeleton through only one bone - the clavicle at the coracoclavicular and acromioclavicular joints
coracoid process
(TG2-03)
a beak-like process that projects anteriorly from the lateral end of the superior border of the scapula it is the attachment site for the short head of the biceps brachii m., the coracobrachialis m., the pectoralis minor m. and the coracoacromial and coracoclavicular ligaments (Greek, korax = crow + eidos = appearance. The coracoid process of the scapula is shaped like a crow's beak)
scapular notch a notch on the superior border of the scapula located medial to the attachment of the coracoid process it is bridged by the superior transverse scapular ligament; the suprascapular a. passes superior to the superior transverse scapular ligament and the suprascapular n. passes inferior to it (Army goes over the bridge, Navy goes under the bridge)
acromion(Practical) a broad, flat process located at the lateral end of the scapular spine it articulates with the clavicle through a synovial joint (acromioclavicular joint) (Latin, akron = tip + omos = shoulder, therefore the tip of the shoulder)
supraspinous fossa a broad depression located superior to the spine of the scapula it is the site of origin of the supraspinatus m.
infraspinous fossa a broad depression located inferior to the spine of the scapula it is the site of origin of the infraspinatus m.
humerus
(N420,N421, TG2-03A, TG2-03B, Practical)
  the bone of the arm (brachium) the humerus articulates proximally with the scapula at the glenoid fossa; it articulates distally with the radius and ulna at the elbow joint
head(Practical) the smooth, rounded proximal end of the humerus it articulates with the glenoid cavity of the scapula to form the shoulder joint
anatomical neck the constricted region located inferolateral to the head it is located at the circumference of the smooth articular surface of the head
surgical neck the proximal part of the shaft of the humerus it is located inferior to the greater and lesser tubercles; it is a site of frequent fracture; fractures of the surgical neck of the humerus endanger the axillary n. and the posterior circumflex humeral a.
greater tubercle the large projection located lateral to the head of the humerus it is the attachment site of the supraspinatus, infraspinatus & teres minor mm.
lesser tubercle the projection located lateral to the head of the humerus on the anterior surface it is the insertion site of the subscapularis m.
intertubercular groove the groove on the anterior surface of the humerus that is located between the crest of the greater tubercle and the crest of the lesser tubercle it is occupied by the tendon of the long head of the biceps brachii m.; the transverse humeral ligament spans the intertubercular groove and holds the biceps tendon in place; it is the attachment site for the tendon of the pectoralis major (lateral lip), teres major (medial lip), and latissimus dorsi (floor) (Latin, tuber = knobby process, nodule)
crest of the greater tubercle the ridge of bone on the anterior surface of the humerus extending inferiorly from the greater tubercle it forms the lateral lip of the intertubercular groove; it is the attachment site for the transverse humeral ligament and the pectoralis major m.
crest of the lesser tubercle the ridge of bone on the anterior surface of the humerus extending inferiorly from the lesser tubercle it forms the medial lip of the intertubercular groove; it is the attachment site for the transverse humeral ligament and the teres major m.
deltoid tuberosity the roughened process on the lateral surface of the mid-shaft of the humerus it is the insertion site of the deltoid m.
lateral epicondyle a knob-like projection on the lateral side of the humerus proximal to the capitulum it is the site of attachment of the common extensor tendon which is the origin of several forearm extensor muscles (extensor carpi radialis brevis m., extensor digitorum m., extensor digiti minimi m., extensor carpi ulnaris m. and supinator m.); inflammation of the attachment of the common extensor tendon is called lateral epicondylitis which is also known as "tennis elbow" (Greek, kondylos = the knob formed by the knuckle of any joint)
medial epicondyle a knob-like projection on the medial side of the humerus proximal to the trochlea it is the attachment site of the common flexor tendon which is the origin for the superficial group of forearm flexor muscles (pronator teres m., flexor carpi radialis m., palmaris longus m., flexor carpi ulnaris m. and flexor digitorum superficialis m.); inflammation of the attachment of the common flexor tendon is called medial epicondylitis which is also known as "golfer's elbow"; the ulnar nerve is in contact with bone as it courses posterior to the medial epicondyle where it is susceptible to injury from blunt trauma or fracture Greek, kondylos = the knob formed by the knuckle of any joint)
radial groove (Practical) the groove that spirals around the posterior surface of the shaft of the humerus it is a depression for the radial n. and the deep brachial vessels; fracture of the humerus at mid-shaft can injure the radial nerve and deep brachial vessels because they are in contact with bone at this location
ulna
(N436,N439, TG2-04AB, Practical)
  the bone on the medial side of the forearm (antebrachium) the ulna articulates proximally with the trochlea of the humerus and the head of the radius; it articulates distally with the ulnar notch of the radius (Latin, ulna = elbow or arm)
  olecranon the proximal end of the ulna it is the insertion site of the tendon of the triceps brachii m.; when the elbow is extended, the olecranon of the ulna engages the olecranon fossa of the humerus (Greek, olecranon = the head or point of the elbow)
  coronoid process the anterior projection of bone located distal to the trochlear notch (Greek, coronoid = resembles a crow)
styloid process a small projection from the distal surface of the head of the ulna it is the site of attachment of the articular disk of the distal radioulnar joint
radius
(N436,N439, TG2-04AB, Practical)
  the bone on the lateral side of the forearm (antebrachium) the radius pivots on its long axis and crosses the ulna during pronation
  head the rounded proximal end of the radius it has a smooth, rounded surface for articulation with the ulna; the head of the radius is encircled by the annular ligament (4/5 of a circle) and the radial notch of the ulna (1/5 of a circle)
  neck the constricted area of the radius located distal to the head the annular ligament of the radius surrounds the head of the radius, not the neck of the radius
  radial tuberosity a roughened area on the anteromedial surface of the radius located just distal to the neck it is the insertion site of the tendon of the biceps brachii m.
styloid process the distal-most projection from the lateral side of the radius the radial styloid process projects lateral to the proximal row of carpal bones

Muscles

Muscle Origin Insertion Action Innervation Blood Supply Notes Image
pectoralis major
(N188, TG2-12)
medial 1/2 of the clavicle, manubrium & body of sternum, costal cartilages of ribs 2-6, sometimes from the rectus sheath of the upper abdominal wall crest of the greater tubercle of the humerus flexes and adducts the arm, medially rotates the arm medial and lateral pectoral nerves (C5-T1) pectoral branches of thoracoacromial artery the deep fascia on its anterior surface should not be fused to the fascia of the mammary gland - if it is, this is an important clinical sign indicating breast disease (Latin, pectus = breast bone)
pectoralis minor
(N188, N189, N428, TG2-12, TG4-07)
ribs 3-5 coracoid process of the scapula draws the scapula forward, medialward, and downward medial pectoral nerve (C8, T1) pectoral branches of thoracoacromial artery branches of medial pectoral nerve usually pierce pectoralis minor to reach the pectoralis major muscle (Latin, pectus = breast bone)
serratus anterior
(N191, TG4-07, Practical1, Practical2)
ribs 1-8 or 9 medial border of the scapula on its costal (deep) surface it draws the scapula forward; the inferior fibers rotate the scapula superiorly long thoracic nerve (from ventral rami C5-C7) lateral thoracic artery a lesion of long thoracic nerve will cause winging of the scapula (i.e., the medial border of the scapula falls away from the posterior chest wall and looks like an angel's wing) (Latin, serratus = to saw)
deltoid
(N424, TG2-07, Practical)
lateral one-third of clavicle, acromion, lower lip of the crest of the spine of the scapula deltoid tuberosity of the humerus abducts arm; anterior fibers flex & medially rotate arm; posterior fibers extend & laterally rotate arm axillary nerve (C5,6) from posterior cord of brachial plexus posterior humeral circumflex artery; deltoid branch of thoracoacromial artery deltoid is the principle abductor of the arm but due to poor mechanical advantage it cannot initiate this action; assisted by supraspinatus
teres major
(N424, TG2-07, TG2-08)
dorsum of the inferior angle of scapula crest of lesser tubercle of humerus adducts arm, medially rotates arm, assists in arm extension lower subscapular nerve (C5,6) from the posterior cord of the brachial plexus thoracodorsal and circumflex scapular artery teres major inserts beside the tendon of latissimus dorsi, and assists latissimus in its actions (Latin, teres = round)
rotator cuff
supraspinatus
(N425, N426, TG2-08, TG2-16A, TG2-16B, TG2-16C, Practical)
supraspinatus fossa greater tubercle of humerus (highest facet) abduct arm (initiate abduction) suprascapular nerve (C5,6) from superior trunk of brachial plexus suprascapular artery supraspinatus initiates abduction of the arm, then the deltoid muscle completes the action
infraspinatus
(N425, N426, TG2-08, TG2-16A, TG2-16B, TG2-16C, Practical1, Practical2, Practical3)
infraspinatus fossa greater tubercle of humerus (middle facet) laterally rotate arm suprascapular nerve suprascapular and circumflex scapular artery infraspinatus, supraspinatus, teres minor and subscapularis are the rotator cuff muscles
teres minor
(N425, N426, TG2-08, TG2-16A, TG2-16B, TG2-16C, Practical)
upper 2/3 of the lateral border of the scapula greater tubercle of humerus (lowest facet) laterally rotates arm axillary nerve circumflex scapular artery fixes head of humerus in glenoid fossa during abduction & flexion of arm
subscapularis
(N425, N426, TG2-08, TG2-16A, TG2-16B, TG2-16C)
medial two-thirds of costal surface of scapula (subscapular fossa) lesser tubercle of humerus medially rotates arm; assists extension of arm upper and lower subscapular nerves (C5,6) axillary artery subscapularis, supraspinatus, infraspinatus, and teres minor are the rotator cuff muscles
biceps brachii
(N431, TG2-17)
short head: tip of coracoid process; long head: supraglenoid tubercle of scapula tuberosity of radius flexes forearm, flexes arm (long head), supinates musculocutaneous nerve (C5,6) brachial artery a powerful supinator only if the elbow is flexed
brachialis
(N431, TG2-17)
anterior surface of lower one-half of humerus and intermuscular septa ulnar tuberosity of ulna flexes forearm musculocutaneous nerve (C5,6) brachial artery powerful flexor
coracobrachialis
(N431, TG2-17, Practical)
coracoid process of scapula medial humerus at mid-shaft flexes and adducts arm musculocutaneous nerve (C5,6) brachial artery musculocutaneous nerve passes through the coracobrachialis muscle to reach the other arm flexors (biceps brachii and brachialis)
triceps brachii
(N432, TG2-18A, TG2-18B, Practical)
long head: infraglenoid tubercle of scapula; lateral head: posterolateral humerus & lateral intermuscular septum; medial head: posteromedial surface of inferior 1/2 of humerus olecranon process of the ulna extends forearm; long head extends and adducts arm radial nerve deep brachial artery long head of triceps separates the triangular and quadrangular spaces (teres major, teres minor and the humerus are the other boundaries)
anconeus
(N432,N444, TG2-18)
lateral epicondyle lateral side of olecranon and upper one-fourth of ulna extends forearm nerve to anconeus from radial nerve middle collateral and interosseous recurrent artery (Greek, ankon = elbow or a bend)

Nerves

Nerve Source Branches Motor Sensory Notes
intercostal n.
(N180, N192, N257, TG1-17, TG4-11)
ventral primary rami of spinal nerves T1-T11 lateral & anterior cutaneous brs. intercostal muscles; abdominal wall muscles (via T7-T11); muscles of the forearm and hand (via T1) skin of the chest and abdomen anterolaterally; skin of the medial side of the upper limb (via T1-T2) intercostal n. travels below the posterior intercostal a. in the costal groove (Latin, costa = rib)
brachial plexus
(N429,N430, TG2-14, TG2-13, Practical1, Practical2, Practical3, Practical4)
ventral primary rami of C5-8 & T1 dorsal scapular, long thoracic, n. to subclavius, suprascapular, lateral & medial pectoral, medial brachial & antebrachial cutaneous, upper, middle & lower subscapular, musculocutaneous, ulnar, median, axillary, radial muscles of upper limb, excluding trapezius skin of upper limb axons from spinal cord levels C5-T1 are mixed (braided) in the brachial plexus and repackaged into terminal branches so that each branch contains axons from several spinal cord levels (Latin, plexus = a braid. A network of nerves, blood vessels, or lymphatic vessels)
dorsal scapular
(N429, TG2-14, Practical1, Practical2)
brachial plexus (C5)   rhomboid major & minor; levator scapulae   passes through scalenus medius
long thoracic
(N429,N190, TG2-13, TG2-14)
brachial plexus (C5-C7)   serratus anterior   located on superficial surface of serratus anterior; lesion causes scapular winging, hence the saying "C5, 6, & 7 keep the wings from heaven"
lateral cord
(N429, N474, TG2-13, TG2-14)
union of anterior divisions of upper & middle trunks lateral pectoral, lateral root of median n., musculocutaneous anterior arm; contributes to anterior forearm & thenar compartment lateral forearm; contributes to palmar hand  
medial cord
(N430, TG2-14)
anterior division of lower trunk medial pectoral, medial brachial cutaneous, medial antebrachial cutaneous, medial root of median n., ulnar fl. carpi ulnaris & medial half of fl. dig. profundus, contributes to other anterior forearm muscles; hand muscles medial forearm & hand  
posterior cord
(N430, TG2-13, TG2-14)
posterior divisions of upper, middle, & lower trunks upper, middle, & lower subscapular, axillary, radial deltoid, teres major & minor, subscapularis, posterior arm & forearm posterior arm & forearm, posterolateral hand  
suprascapular
(N429, N426, TG2-08, TG2-14, Practical)
superior trunk of the brachial plexus (C5-C6) no named branches supraspinatus, infraspinatus no cutaneous branches passes through the suprascapular notch inferior to the superior transverse scapular ligament
lateral pectoral
(N429, TG2-13, TG2-14, Practical)
lateral cord of brachial plexus   pectoralis major   communicates with medial pectoral n. anterior to axillary a.; pierces clavipectoral fascia
musculocutaneous
(N474, TG2-13, TG2-14, Practical)
lateral cord of brachial plexus (C5,6) lateral antebrachial cutaneous coracobrachialis, biceps brachii, brachialis skin of lateral side of forearm pierces coracobrachialis
medial pectoral
(N429, TG2-13, Practical1, Practical2)
medial cord of the brachial plexus   pectoralis minor & major   communicates with lateral pectoral n. anterior to axillary a.; pierces pectoralis minor
medial brachial cutaneous
(N433,N479, TG2-13, TG2-14)
medial cord of brachial plexus     skin of the medial side of the arm communicates with intercostobrachial n. (Latin, cutis = skin)
medial antebrachial cutaneous
(N433,N479, TG2-13, TG2-14)
medial cord of brachial plexus     skin of medial side of forearm travels with basilic vein for part of course (Latin, cutis = skin)
ulnar
(N433,N476, TG2-13, TG2-14, Practical1, Practical2, Practical3)
medial cord of the brachial plexus palmar cutaneous br., dorsal br., superficial & deep br. flexor carpi ulnaris, flexor digitorum profundus (ulnar half), abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi, ulnar 2 lumbricals, palmar & dorsal interossei, adductor pollicis skin of medial side of wrist & hand & ulnar 1 1/2 digits on palmar side and 2 1/2 digits dorsally motor to most of the muscles of the hand (Latin, ulna = elbow or arm)
upper subscapular
(N429, TG2-13, TG2-14)
posterior cord of brachial plexus   subscapularis (superomedial part)    
thoracodorsal (middle subscapular)N426, TG2-13, TG2-14) posterior cord of brachial plexus   latissimus dorsi    
lower subscapular
(N426, TG2-13, TG2-14)
posterior cord of brachial plexus   subscapularis (lateral part), teres major    
radial
(N477,N478, TG2-13, TG2-14, Practical1, Practical2)
posterior cord of brachial plexus posterior brachial cutaneous, inferior lateral brachial cutaneous, posterior antebrachial cutaneous, superficial & deep br. triceps brachii, anconeus, brachioradialis, extensor carpi ulnaris, extensor carpi radialis longus & brevis, extensor digitorum, extensor digiti minimi, supinator, abductor pollicis longus, extensor pollicis longus & brevis, extensor indicis skin of posterior arm, forearm & hand motor to the extensor muscles of the arm and forearm
axillary
(N426, TG2-13, TG2-14. Practical1, Practical2)
posterior cord of brachial plexus superior lateral brachial cutaneous nerve deltoid, teres minor skin of upper lateral arm endangered by surgical neck fractures
median
(N473,N475, TG2-13, TG2-14, Practical1, Practical2)
lateral & medial cords of brachial plexus anterior interosseous, palmar br., recurrent (motor) br., common palmar digital ns. (1st-3rd) pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, flexor digitorum profundus (radial half), flexor pollicis longus, pronator quadratus, abductor pollicis brevis, flexor pollicis brevis, opponens pollicis, radial 2 lumbricals skin of radial half of palm & palmar side of radial 3 1/2 digits (and nail bed for these digits) motor to the flexor muscles of the forearm (except flexor carpi ulnaris and the medial 1/2 of the flexor digitorum profundus),the muscles of the thenar compartment and the lateral 2 lumbricals
intercostobrachial
(N429,N473,N479)
lateral cut. branch of 2nd intercostal     floor of axilla, medial and posterior surfaces of arm communicates with the medial brachial cutaneous n.

Arteries

Artery Source Branches Supply Notes
suprascapular
(N426, TG2-08, N427TG2-15, Practical)
thyrocervical trunk muscular supraspinatus & infraspinatus, shoulder joint anastomoses with the circumflex scapular a. and the dorsal scapular a. to form the scapular anastomosis
axillary
(N184,N189, TG2-15A, TG2-15B, Practical)
subclavian (continuation of the subclavian lateral to the 1st rib) 1st part: superior thoracic; 2nd part: thoracoacromial, lateral thoracic; 3rd part: ant. & post. humeral circumflex, subscapular shoulder & upper limb pectoralis minor crosses the axillary artery anteriorly and is used to delineate the 3 parts mentioned at left (Latin, axillary = armpit)
superior thoracic axillary, 1st part muscular intercostal spaces 1 & 2 laterally  
thoracoacromial
(N427, TG2-15, Practical1, Practical2)
axillary, 2nd part pectoral br., clavicular br., acromial br., deltoid br. pectoralis major & minor, subclavius, deltoid, shoulder joint  
lateral thoracic
(N191,N427, TG2-15A, TG2-15B)
axillary, 2nd part muscular serratus anterior & adjacent muscles, skin & fascia a rare artery in that it enters the serratus anterior from its superficial surface
subscapular
(N427, TG2-15A, TG2-15B)
axillary, 3rd part circumflex scapular, thoracodorsal subscapularis, teres major, teres minor, infraspinatus, latissimus dorsi anastomoses with suprascapular, dorsal scapular & deep br. of transverse cervical
circumflex scapular
(N427, TG2-09A, TG2-15)
subscapular muscular teres major & minor, infraspinatus anastomoses with suprascapular & dorsal scapular branches (Latin, circum- = around + -flex = to bend)
thoracodorsal
(N427, TG2-15A, TG2-15B)
subscapular muscular latissimus dorsi  
anterior circumflex humeral
(N427, TG2-09A, TG2-15, Practical)
axillary, 3rd part muscular arm muscles near surgical neck of humerus  (Latin, circum- = around + -flex = to bend)
posterior circumflex humeral
(N427, TG2-09A, TG2-15)
axillary, 3rd part muscular arm muscles near surgical neck of humerus passes through quadrangular space with axillary nerve
brachial
(N434,N429, TG2-17, TG2-19, Practical)
axillary (continuation distal to teres major m.) deep brachial, sup. ulnar collateral, nutrient, inf. ulnar collateral; terminal branches are the radial & ulnar arm, forearm & hand normally terminates at the level of the elbow, but high branching may occur
deep brachial
(N434, TG2-18, TG2-19)
brachial ascending br., terminal branches are the middle collateral & radial collateral post. arm  

Veins

Vein Tributaries Drains Into Regions Drained Notes
cephalic v.
(N424, N428, N479, TG2-02, TG2-12A, TG2-12B, Practical)
lateral side of the dorsal venous arch of the hand; superficial veins of the forearm axillary vein superficial parts of the lateral hand and lateral forearm median cubital vein usually shunts some of the blood collected by the cephalic v. to the basilic v. (Latin/Greek, kephale = head)
basilic
(N479, N480, TG2-02, Practical)
dorsal veins of hand medially; superficial veins of forearm, median cubital vein unites with brachial vein(s) to form the axillary vein superficial parts of medial hand & medial forearm connects with deep veins of the forearm via perforating veins
median cubital
(N479, TG2-02, Practical1, Practical2)
cephalic basilic superficial parts of hand & forearm a median antebrachial vein is possible and, when present, it may drain into the median cubital vein
dorsal venous network of hand
(N480, TG2-02, Practical)
dorsal metacarpal veins medially into basilic v. and laterally into cephalic v. superficial, dorsal aspect of digits unlike the foot, a distinct arch may be absent in the hand, replaced by a dorsal venous network of veins

Lymphatics of the Axillary Region

Structure Location Afferents from Efferents to Regions drained Notes
parasternal nodes
(N428, TG2-11)
lateral border of sternum, along the course of the internal thoracic vessels anterior phrenic nodes, lymphatic vessels from the anterior thoracic wall larger lymphatic vessels in the root of the neck medial side of the mammary gland; medial part of the anterior chest wall and muscles parasternal nodes constitute an important drainage pattern in cases of cancer of the mammary gland; one or two parasternal nodes may be found in the anterior end of intercostal spaces 1-6; also known as: sternal nodes
axillary nodes
(N428, TG2-11)
axilla cubital nodes; lymphatic vessels from the upper limb, thoracic wall and subscapular region efferents vessels form the subclavian trunk, some drainage to inferior deep cervical nodes upper limb, most of the mammary gland, some of the anterolateral chest wall, posterior thoracic wall and scapular region axillary nodes number from 20 to 30 and are organized in five groups based on their position within the axilla: 1) pectoral nodes, along the lateral border of the pectoralis major m.; 2) lateral nodes, located along the distal axillary v.; 3) central nodes, centrally located along axillary v.; 4) subscapular nodes, located along the subscapular v. and its tributaries; 5) apical nodes, located at the apex of axilla
pectoral nodes
(N184, TG2-11)
lateral border of pectoralis major most of breast, anterolateral chest wall & muscles central axillary nodes anterolateral thoracic wall and muscles, including most of the mammary gland also known as anterior axillary or level I nodes; an important group of nodes to examine during breast exam
lateral axillary
(N184, TG2-11)
along distal axillary v. small nodes in cubital fossa central axillary nodes upper limb
posterior axillary
(N184, TG2-11)
anterior to subscapularis m. central axillary nodes posterior shoulder a.k.a. subscapular nodes
central axillary
(N184, TG2-11)
along axillary v. posterior to pectoralis minor m. lateral, anterior & posterior axillary nodes apical axillary nodes upper limb, breast, posterior shoulder, lateral chest wall a.k.a. level II nodes
apical axillary
(N184, TG2-11)
along axillary v. medial to pectoralis minor m. at apex of axilla central axillary nodes subclavian lumph trunk upper limb, breast, posterior shoulder, lateral chest wall a.k.a. level III nodes

Topographic Anatomy

Structure/Space Boundaries Significance
quadrangular space
(TG2-08)
boundaries: medial - long head triceps tendon, lateral - humerus, superior - teres minor, inferior - teres major significance: traversed by the axillary nerve & posterior humeral circumflex artery
subacromial/subdeltoid bursa
(TG2-42)
between the deltoid, the supraspinatus tendon and the glenohumeral joint facilitates movement of the supraspinatus tendon and the deltoid
triangular space
(TG2-08)
boundaries: lateral - long head triceps tendon, superior - teres minor, inferior - teres major significance: traversed by the circumflex scapular artery
anterior compartment separated from the posterior compartment by the medial and lateral intermuscular septa contains the biceps brachii, coracobrachialis, and brachialis mm. and musculocutaneous n.
anterior axillary fold anterior boundary of the axilla inferior border of the sternocostal head of the pectoralis major
bicipital aponeurosis
(TG2-17)
a triangular membranous band that runs from the biceps tendon across the cubital fossa and merges with the antebrachial fascia passes obliquely over the brachial artery and median nerve (Greek, aponeurosis = a broad, flat nerve)
medial intermuscular septum extends from the deep surface of the brachial fascia to the medial supracondylar ridges of the humerus divides the arm into anterior and posterior compartments
lateral intermuscular septum extends from the deep surface of the brachial fascia to the lateral supracondylar ridges of the humerus divides the arm into anterior and posterior compartments
posterior axillary fold posterior border of the axilla composed of skin and muscular tissue of the latissimus dorsi and teres major
neurovascular compartment of arm formed by a split in the medial intermuscular septa contains the median & medial antebrachial cutaneous nn. and brachial vessels
posteror compartment of arm separated from the anterior compartment by the medial and lateral intermuscular septa contains triceps brachii, radial n., and deep brachial vessels, as well as ulnar n. in its distal, medial half
cubital fossa superior - line between humeral epicondyles, medial - pronator teres, lateral - brachioradialis site for phlebotomy

Viscera/Fascia

Organ/Part of Organ Location/Description Notes
clavipectoral fascia
(N188,N428, TG2-12, TG4-07)
deep fascia attaching to clavicle, surrounding subclavius m., thickened below as costocoracoid ligament, extending inferiorly to pectoralis minor as costocoracoid membrane (pierced by cephalic v., lateral pectoral n., thoracoacromial a.), encloses pectoralis minor, extends inferolaterally to attach to axillary fascia as suspensory ligament of axilla
mammary gland
(N182, TG2-10)
located anterior to pectoralis major m. from rib 2/3 to rib 6/7 the breast, a modified sweat gland, comprises glandular tissue arranged in up to 20 lobules, surrounded by subcutaneous connective tissue and supported by suspensory ligaments
lactiferous ducts
(N182, TG2-10A, TG2-10B)
drain the lobules of the mammary gland at the nipple beneath the nipple, the ducts dilate to form lactiferous sinuses
areola
(N182, TG2-10)
darkly pigmented skin surrounding the nipple
brachial fascia
(N479, TG2-02)
sheath of deep fascia enclosing the arm that is continuous superiorly with the pectoral and axillary layers of fascia attached inferiorly to the epicondyles of the humerus and the olecranon of the ulna and is continuous with the antebrachial fascia
antebrachial fascia
(N480, TG2-02)
anterior and posterior thickening forming the extensor retinaculum; immediately distal but deeper to the palmar carpal ligament it forms the flexor retinaculum formation of the carpal tunnel through which the median n. and flexor tendons pass

Clinical Terms

Term Definition
anomalies/variations deviation or departure from the normal or common order, form, or rule
gynecomastia excessive development of the male mammary glands, sometimes secreting milk. This can be idiopathic, or as a result of an underlying disease process. (Greek, gyn = female + mastos = breast)
axillary tail (of Spence) part of the mammary gland may extend along the inferolateral edge of the pectoralis major toward the axilla (armpit), forming an axillary tail (of Spence). This portion of breast tissue is in the upper-outer quadrant of the breast which is important because 50% of breast cancer is located in this quadrant and in the axillary tail
supernumerary nipples (polythelia) more than the normal number of nipples, may be on the breast or other parts of the body-found along the "milk line" from axilla to groin. These accessory nipples resemble raised nevi (commonly called "moles").
supernumerary breasts (polymastia) a condition in which more than two breasts are present
carcinoma any of the various types of malignant (invasive) neoplasm derived from epithelial tissue in several sites, occuring more frequently in skin, bronchi, stomach, and prostate gland in men, and in the breast, cervix, and skin in women (Greek, carcino- = cancer + -oma = tumor)
mastectomy/lumpectomy amputation of the breast or of an affected portion (Greek, mastos = breast + -ectomy = excision)
mastitis inflammation of the mammary gland (Greek, mastos = breast + -itis = inflammation)
scintigraphy record indicating the intensity, location, and distribution of radioactivity in tissue following the use of radioactive tracer substances
mammogram special imaging examination of the breast to detect breast cancer. The American Cancer Society currently recommends that screening should begin annually at the age of 40 (and earlier in those patients with a family history of breast cancer).
venipuncture puncture of a vein (usually in the arm) with a hollow bore needle for the purpose of obtaining a blood specimen; risks are localized pain, hematoma (accumulation of blood under the skin), bleeding, secondary infection (rare) and fainting (in susceptible individuals); a common upper extremity vein is the median cubital vein
Erb-Duchenne palsy injury to the superior roots of the brachial plexus, C5 and C6, leads to paralysis of the supraspinatus and infraspinatus muscles, and in more severe forms may involve deltoid, biceps, brachialis, coracobrachialis, brachioradialis, teres minor, and subscapularis; the upper limb is adducted at the shoulder, medially rotated, and extended at the elbow. This type of injury can result from too much traction on the neck, or forcible lateral neck bending, as can occur during delivery. This should be suspected when the muscles of the hand are intact, but the Moro reflex is absent in an infant (Moro reflex is similar to the startle reflex, and involves abduction and then adduction of the arms).
Klumpke's palsy a lower brachial plexus injury; occurs when a person grabs something to break a fall or a baby's arm is pulled too much during delivery; the dorsal and ventral roots of the spinal nerves that form the inferior trunk of the brachial plexus (C8 and T1) may be avulsed; the short muscles of the hand are affected, and a clawhand results
radial nerve/Saturday night palsy The radial nerve is often injured when the humerus fractures at mid-shaft; wrist drop is a common clinical manifestation. The deep branch of the radial nerve can be injured by deep puncture wounds to the forearm. The deep branch of the radial nerve is responsible for extending the thumb and the MP joints. Neither deep nor superficial radial nerve injury causes much sensory loss, but cutting the superifical leaves a coin-shaped area distal to the bases of the 1st and 2nd metacarpals without sensation.
rotator cuff tear can lead to rupture of one or more of the tendons of the muscles forming the rotator cuff; acute tears may occur when the arm is violently pushed into abduction; a tear in the rotator cuff may present as pain in the anterosuperior part of the shoulder; tears also follow dislocation of the shoulder
subdeltoid/subacromial bursitis the tendon of the supraspinatus is separated from the coracoacromial ligament, acromion, and deltoid by the subacromial bursa; when this bursa is inflamed (subacromial bursitis), abduction of the arm is extremely painful during of the arc of 50 to 120 degrees (painful arc syndrome); pain may radiate as far distally as the hand, acute pain is also felt lateral to the acromion
painful arc syndrome pain caused by subacromial bursitis; felt during the arc of 50 to 120 degrees

The material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest & Jaye Schlesinger
Published by ILOC, Inc., New York
Copyright © 1995, unauthorized use prohibited.
The excellent editorial assistance of
Dr. Pat Tank, UAMS
is gratefully acknowledged.