 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Anatomy Tables - Axilla, Posterior Shoulder, & Arm
|
|||||||||||||
|
|
||||||||||||
|
|||||||||||||
Anatomy Tables - Axilla, Posterior Shoulder, & Arm |
|||||||||||||
|
|||||||||||||
Osteology |
|||
|---|---|---|---|
| Bone | Structure | Description | Notes |
| 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 | |
| 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) | |
| 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 "tennis 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 | Notes | Image |
| 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 | 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 | 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 | 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 | 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 | 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) | 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) | 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) | powerful flexor | ) |
| coracobrachialis (N431, TG2-17, Practical) |
coracoid process of scapula | medial humerus at mid-shaft | flexes and adducts arm | musculocutaneous nerve (C5,6) | musculocutaneous nerve passes through the coracobrachialis muscle to reach the other arm flexors (biceps brachii and brachialis) | ) |
| 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) | 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) | ) |
| 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 | 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 | (Greek, ankon = elbow or a bend) | ) |
Nerves |
|||||
|---|---|---|---|---|---|
| Nerve | Source | Branches | Motor | Sensory | Notes |
| 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 | |
Lymphatics of the Axillary Region |
|||||
|---|---|---|---|---|---|
| Structure | Location | Afferents from | Efferents to | Regions drained | Notes |
| axillary nodes (N184, TG2-11) |
axilla | efferents form subclavian trunk | upper limb, most of breast, some anterolateral chest wall | axillary nodes are grouped as: 1) pectoral/anterior nodes, along lower border of pectoralis major; 2) lateral nodes, distal along axillary v.; 3) central nodes, centrally located along axillary v.; 4) subscapular/posterior nodes, along subscapular v. & tributaries; 5) apical nodes, at apex of axilla, receiving lymph from all other groups | |
| 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 |
| 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. |
|
||
| Copyright© 2000 The University of Michigan. Unauthorized use prohibited. |
|
|
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
.jpg',%20'left',%20860,%20860)){kind=link}
.jpg',%20'left',%20860,%20860)){kind=link}
.jpg',%20'left',%20860,%20860)){kind=link}
){kind=link}
){kind=link}
){kind=link}
.jpg',%20'left',%20860,%20860)){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}
){kind=link}