Arm

Gross Anatomy


Arm and Cubital Fossa



Anatomy Tables for Today's Topic

Bones of the Arm and Elbow Region
Muscles of the Arm
Nerves of the Arm and Elbow Region
Arteries of the Arm and Elbow Region
Veins of the Elbow Region
Topographic Anatomy - Cubital Fossa
Joints - Elbow and Proximal Radioulnar

Bones of the Arm and Elbow Region

Bone Structure Description Notes
humerus   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 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 adjacent 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 vessels
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. which are three members of the rotator cuff group
lesser tubercle the projection located on the anterior surface of the proximal end of the humerus it is the insertion site of the subscapularis m., a member of the rotator cuff group
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.
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 tendon of the long head of the biceps in place; it is the attachment site for the tendon of the pectoralis major (lateral lip), teres major (medial lip), and latissimus dorsi (floor)
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.
radial groove 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
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. and extensor carpi ulnaris m.); inflammation of the attachment of the common extensor tendon is called lateral epicondylitis which is also known as "tennis elbow"
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; 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
medial supracondylar ridge a narrow ridge running proximally from the medial epicondyle of the humerus the pronator teres m. takes origin from the common flexor tendon near the most inferior part of the medial supracondylar ridge
lateral supracondylar ridge a narrow ridge running proximally from the lateral epicondyle of the humerus it is the site of origin of the brachioradialis m. and the extensor carpi radialis longus m.
coronoid fossa the depression on the anterior surface of the humerus located proximal to the trochlea near the elbow it accommodates the coronoid process of ulna when the elbow is flexed
radial fossa the depression on the anterior surface of the humerus located proximal to the capitulum near the elbow it accommodates the head of the radius when the elbow is flexed
olecranon fossa the depression on the posterior surface of the humerus located just proximal to the elbow it accommodates the olecranon process of the ulna when the elbow is extended
capitulum the rounded process that caps the distal end of the lateral condyle of the humerus it articulates with the head of the radius; capitulum means "little head"
trochlea the grooved process that caps the distal end of the medial condyle of the humerus it articulates with the trochlear notch of the ulna; the shape of the trochlea and the trochlear notch limits side-to-side movement and guarantees a hinge action; trochlea means "pulley"
ulna   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
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
trochlear notch the crescent shaped notch on the anterior surface of the proximal end of the ulna it is located between the olecranon and the coronoid process; it articulates with the trochlea of the humerus; a ridge within the trochlear notch fits into the groove in the trochlea of the humerus which limits side-to-side movement and guarantees a hinge action
coronoid process the anterior projection of bone located distal to the trochlear notch it is the insertion site of the brachialis m.
radial notch the notch on the lateral surface of the ulna located just distal to the trochlear notch it accommodates the head of the radius; the ends of the annular ligament attach to the anterior and posterior edges of the radial notch of the ulna to encircle the head of the radius
body the long slender midportion of the ulna it is also called the shaft or diaphysis; the interosseous membrane attaches to the entire length of the interosseous border of the body of the ulna
head the distal end of the ulna it is small and rounded for articulation with the radius
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   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.
body the long, slender midportion of the radius it is also known as the shaft or diaphysis; the interosseous membrane attaches to the entire length of the body of the radius along its interosseous border; a fracture of the distal end of the body of the radius with a dorsal displacement of the distal fragment is quite common and is called a Colles' fracture
ulnar notch a shallow notch located on the medial surface of the distal end of the radius it articulates with the head of the ulna
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 of the Arm

Muscle Origin Insertion Action Innervation Artery Notes
anconeus lateral epicondyle of the humerus lateral side of the olecranon and the upper one-fourth of the ulna extends the forearm nerve to anconeus, from the radial nerve interosseous recurrent a. none
biceps brachii short head: tip of the coracoid process of the scapula; long head: supraglenoid tubercle of the scapula tuberosity of the radius flexes the forearm, flexes arm (long head), supinates musculocutaneous nerve (C5,6) brachial a. a powerful supinator when the elbow is flexed; the bicipital aponeurosis, a membranous extension of the biceps brachii tendon, extends across the cubital fossa and protects the structures located there
brachialis anterior surface of the lower one-half of the humerus and the associated intermuscular septa coronoid process of the ulna flexes the forearm musculocutaneous nerve (C5,6) brachial a., radial recurrent a. a powerful flexor
coracobrachialis coracoid process of the scapula medial side of the humerus at mid-shaft flexes and adducts the arm musculocutaneous nerve (C5,6) brachial a. the musculocutaneous nerve usually passes through the coracobrachialis muscle to reach the other arm flexor mm.(biceps brachii and brachialis)
triceps brachii long head: infraglenoid tubercle of the scapula; lateral head: posterolateral humerus & lateral intermuscular septum; medial head: posteromedial surface of the inferior 1/2 of the humerus olecranon process of the ulna extends the forearm; the long head extends and adducts arm radial nerve deep brachial (profunda brachii) a. long head of the triceps separates the triangular and quadrangular spaces (teres major, teres minor and the humerus are the other boundaries); all three heads of origin insert by a common tendon

Nerves of the Arm and Elbow Region

Nerve Source Branches Motor Sensory Notes
musculocutaneous n. lateral cord of the brachial plexus lateral antebrachial cutaneous n. coracobrachialis m., biceps brachii m., brachialis m. skin of the lateral side of the forearm musculocutaneous n. usually passes through the coracobrachialis m.
radial n. posterior cord of the brachial plexus posterior brachial cutaneous n., inferior lateral brachial cutaneous n., posterior antebrachial cutaneous n., superficial and deep brs. muscles of the posterior arm: triceps brachii m., anconeus m.; muscles of the posterior forearm: brachioradialis, extensor carpi ulnaris m., extensor carpi radialis longus m., extensor carpi radialis brevis m., extensor digitorum m., extensor digiti minimi m., supinator m., abductor pollicis longus m., extensor pollicis longus m., extensor pollicis brevis m., extensor indicis m. skin of the posterior arm, forearm and hand all of the muscles on the posterior side of the arm and forearm are innervated by the radial n.

Arteries of the Arm and Elbow Region

Artery Source Branches Supply to Notes
anterior circumflex humeral axillary a., 3rd part unnamed muscular branches deltoid m.; arm muscles near the surgical neck of the humerus anterior circumflex humeral a. anastomoses with the posterior circumflex humeral a.
posterior circumflex humeral axillary a., 3rd part unnamed muscular branches deltoid; arm muscles near the surgical neck of the humerus posterior circumflex humeral a. anastomoses with the anterior circumflex humeral a.; it passes through the quadrangular space with the axillary nerve
brachial axillary a. (brachial a. is the continuation of the axillary a. distal to the teres major m.) deep brachial a., superior ulnar collateral a., nutrient a., inferior ulnar collateral a.; terminal branches are the radial a. and the ulnar a. arm, forearm and hand brachial a. normally terminates by branching within the cubital fossa, but high branching may occur
brachial, deep brachial a. ascending br.; terminal branches are the middle collateral a. and radial collateral a. muscles and tissues of the posterior compartment of the arm deep brachial a. spirals around the shaft of the humerus in the radial groove where it is susceptible to injury in mid-shaft fractures
collateral, inferior ulnar brachial a. unnamed muscular branches lower medial arm anastomoses with the anterior ulnar recurrent a.
collateral, middle deep brachial a. unnamed muscular branches medial head of triceps, anconeus anastomoses with the interosseous recurrent a.
collateral, radial deep brachial a. unnamed muscular branches lower lateral arm travels with the radial nerve; anastomoses with the radial recurrent a.
collateral, superior ulnar brachial a. unnamed muscular branches medial arm muscles travels with the ulnar nerve; anastomoses with posterior ulnar recurrent a.

Veins of the Elbow Region

Vein Tributaries Drains Into Regions Drained Notes
basilic v. medial end of the dorsal venous arch of the hand; superficial veins of the forearm; median cubital v. it unites with the brachial vein(s) to form the axillary v. superficial parts of the medial side of the hand and medial side of the forearm basilic v. communicates with deep veins of the forearm through perforating veins, especially in the cubital region
cephalic v. 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.
median cubital v. cephalic basilic superficial part of the hand and forearm a median antebrachial vein occurs occasionally and, when present, it may drain into the median cubital vein

Topographic Anatomy - Cubital Fossa

Structure/Space Description/Boundaries Significance
cubital fossa a shallow depression on the anterior surface of the elbow region; it is bounded superiorly by an imaginary line between the humeral epicondyles, medially by the lateral border of the pronator teres m. and laterally by the medial border of the brachioradialis m. the median cubital v. crosses this region and is a site for phlebotomy

Joints - Elbow and Proximal Radioulnar

Joint or ligament Description Notes
elbow joint the joint between the distal humerus and the proximal radius and ulna a synovial hinge joint; the elbow joint is a complex joint consisting of humeroradial, humeroulnar and proximal radioulnar articulations all within a common articular capsule; it is strengthened by the ulnar and radial collateral ligaments
radioulnar joint, distal the articulation between the head of the ulna and the ulnar notch of the radius a synovial pivot joint; this joint has a fibrocartilaginous articular disk that attaches to the styloid process of the ulna and the medial side of the distal radius
radioulnar joint, intermediate the articulation formed by the interosseous membrane a syndesmosis; it connects the interosseous border of the ulna to the interosseous border of the radius; proximally directed forces from the hand pass through the radius and are transferred to the ulna through the interosseous membrane
radioulnar joint, proximal the proximal articulation between the radius and ulna that is contained within the capsule of the elbow joint a synovial pivot joint; it is the articulation between the head of the radius and the radial notch of the ulna which is completed by the annular ligament


Other Tables of Interest:


Back Region


Upper Limb

All Anatomy Tables

Tables Organized by System Tables Organized by Region


Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of tables edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2005, Department of Neurobiology and Developomental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.