(26) Arm & Cubital Fossa

medial bicipital groove

divides anterior & posterior compartments of the arm

bicipital aponeurosis

A broad aponeurosis of the biceps brachii located in the cubital fossa of the elbow that separates superficial from deep structures in much of the fossa.

medial epicondyle

medial elevation on the distal end of the humerus. usually bigger than the lateral.

lateral epicondyle

lateral elevation on the distal end of the humerus

olecranon

elbow

intertubercular sulcus

located between greater and lesser tubercles of the humerus where tendon of biceps brachii runs

deltoid tuberosity

raised area on lateral surface of humerus to which deltoid muscle attaches

anatomical neck of humerus

portion of the humerus immediately inferior to the head

surgical neck of humerus

portion of the humerus immediately inferior to the tubercles

capitulum

part of the humerus that articulates with the head of the radius

trochlea

part of the humerus that articulates with the ulna

trochlear notch

part of the ulna that articulates with trochlea of humerus

coronoid fossa

anterior depression of the humerus that receives the coronoid process of the ulna during forearm flexion

coronoid process

hook-shaped part of the ulna that articulates with the coronoid fossa of the humerus during forearm flexion. brachialis attaches.

ulnar tuberosity

roughened area located on the anterior, proximal ulna inferior to the coronoid process where brachialis attaches

radial tuberosity

The rough oval process on the medial and anterior side of the radius, just distal to the neck, where biceps brachii attaches

radial groove

marks the path of the radial nerve on the posterior side of the humerus

Forearm Supination

Rotating the forearm so the palm faces up. Radius & ulna are parallel.

Forearm Pronation

Rotating the forearm so the palm faces down. radius is crossed over ulna.

elbow joints

humeroulnar, humeroradial, proximal radioulnar

humeroulnar joint

hinge joint between trochlea of humerus & trochlear notch of ulna. allows flexion/extension. located medially.

humeroradial joint

ball & socket/gliding joint between capitulum of humerus and head of radius. allows flexion/extension & pronation/supination. located laterally.

proximal radioulnar joint

pivot joint between head of radius articulates & radial notch of ulna. allows pronation/supination.

Fascial Compartments of arm

anterior and posterior compartments, divided by medial and lateral intermuscular septa. Very tight & thick.

anterior arm compartment

contains arm flexors: biceps brachii, coracobrachialis, brachialis. Supplied by the brachial artery, innervated by the musculocutaneous nerve (C5-C7)

posterior arm compartment

contains arm extendors: triceps brachii, anconeus. Supplied by the deep brachial artery (profunda brachii), innervated by the radial nerve (C5-T1).

Biceps Brachii

Two-headed anterior arm muscle with a more lateral long head that originates at the supraglenoid tubercle/glenoid labrum & a more medial short head that originates at the coracoid process, both of which insert at the radial tuberosity & the deep fascia of the forearm.

-Both heads function as forearm supinators & flexors (when supine), & weak arm flexors

-Short head also functions as a weak adductor & to resist shoulder dislocation

-Innervated by the musculocutaneous nerve (C5-C7)

tendon of long head of biceps brachii

courses through the glenohumeral joint deep to fibrous

capsule but superficial to synovial membrane

Biceps Tendon Rupture

Tearing of biceps tendon that results in the muscle belly bulging out & creating the "Popeye sign." Can occur at proximal long head, distal long head, or short head.

proximal biceps tendon rupture

rupture of the long head of biceps brachii tendon at the supraglenoid tubercle

-Most common type of biceps tendon rupture (96%)

-Commonly caused by degenerative changes within the tendon

-Non-operative treatment is usually effective

Distal Biceps Tendon Rupture

rupture of the long head of biceps brachii tendon at the radial tuberosity

-Not very common (3%)

-More common in males, strength athletes, anabolic steroid users, & pro strongman athletes

-Requires surgery

short head biceps tendon rupture

most rare type of biceps tendon rupture (1% of cases)

Coracobrachialis

anterior arm muscle that runs from the coracoid process to the medial midshaft of the humerus. Functions to adduct the arm, weakly flex the arm, & resist shoulder dislocation.

-Innervated by the musculocutaneous nerve (C5-C7)

Brachialis

anterior arm muscle that runs from the distal half of the anterior humerus to the coronoid process & tuberosity of the ulna. Functions only to flex the forearm, both when pronated or supine ("the king of flexion").

-Innervated by the musculocutaneous nerve (C5-C7)

triceps brachii

Three-headed posterior arm muscle with a long head that originates at the infraglenoid tubercle, a lateral head that originates at the posterior humerus lateral to the radial groove, & a medial head that originates at the shaft of the humerus medial to the radial groove, all of which insert at the olecranon process of the ulna.

-All heads, but especially the medial head, function to extend the forearm

-The long head also functions to extend the arm & adduct the arm, & is important for shoulder stability

-Innervated by the radial nerve (C5-T1)

Anconeus

posterior arm muscle that runs from the posterior humerus to the lateral surface of the proximal ulna. Functions to assist triceps brachii in forearm extension.

-Innervated by the radial nerve (C5-T1)

collateral arteries

arteries that meet recurrent arteries in anastomoses around the elbow. Run in same direction as source (toward the fingers)

recurrent arteries

arteries that meet collateral arteries in anastomoses around the elbow. Run in opposite direction of source (toward the shoulder)

brachial artery

Continuation of the axillary artery after the inferior border of teres major that supplies the arm. Branches into the deep brachial artery, super ulnar collateral artery, inferior ulnar collateral artery, radial artery, and ulnar artery.

deep brachial artery (profunda brachii)

first branch of the brachial artery that runs closely with the humerus. Branches into Radial collateral artery & Middle collateral artery

radial collateral artery

Branch of the profunda brachii artery that runs lateral to the humerus & anastomoses with the radial recurrent artery.

middle collateral artery

Branch of the profunda brachii artery that runs posterior to the humerus

superior ulnar collateral artery

branch of the brachial artery that runs with the ulnar nerve & anastomoses with the posterior ulnar recurrent artery.

inferior ulnar collateral artery

branch of the brachial artery that begins just above the elbow & anastomoses with the anterior ulnar recurrent artery.

radial artery

one of the terminal branches of the brachial artery that arises in the cubital fossa & supplies the lateral forearm. Branches include the radial recurrent artery.

radial recurrent artery

branch of the radial artery that curves to run superiorly & anastomoses with the radial collateral artery.

ulnar artery

one of the terminal branches of the brachial artery that arises in the cubital fossa & supplies the medial forearm. Branches include the anterior & posterior ulnar recurrent arteries.

anterior ulnar recurrent artery

branch of the ulnar artery that curves to run superiorly & anastomoses with the inferior ulnar collateral artery

posterior ulnar recurrent artery

branch of the ulnar artery that curves to run superiorly & anastomoses with the superior ulnar collateral artery

Medial Bicipital Groove

located between biceps brachii and triceps brachii. Brachial artery & median nerve travel in the cleft

-Place where pulse of the brachial artery can be felt

superficial veins of the arm

cephalic vein

basilic vein

median cubital vein

cephalic vein

large lateral superficial vein of the arm that drains into the axillary vein

basilic vein

large medial superficial vein of the arm that merges with the brachial veins to form the axillary vein

median cubital vein

Superficial vein located near the middle of the elbow area that connects the basilic & cephalic veins.

-Often first choice for venipuncture

deep veins of the arm

brachial veins

brachial veins

paired deep arm veins that merge with the basilic vein to form the axillary vein

route of ulnar nerve

branches from medial cord → follows brachial artery into arm→ deviates posteriorly → crosses elbow posterior to the medial

epicondyle with the superior ulnar collateral artery → cubital tunnel → anterior forearm & hand

-Gives off an articular branch to the elbow

funny bone sensation

caused by exposure of ulnar nerve at its most medial position

Cubital tunnel

Canal formed by the posterior condylar groove and ligament, the cubital tunnel retinaculum, attaching to medial epicondyle to the olecranon

Cubital Tunnel Syndrome

paresthesia or numbness in ulnar nerve distribution and

weakness/atrophy of hand muscles due to compression of ulnar nerve in cubital tunnel

route of median nerve

branches from lateral and medial cords → follows brachial artery in arm → cubital fossa → anterior forearm and hand

-gives off articular branch to elbow

route of musculocutaneous nerve

branches from lateral cord → pierces coracobrachialis → sends branches into biceps brachii & brachialis → continues as

lateral cutaneous nerve of forearm just above elbow

route of radial nerve

branches from from posterior cord → runs through triangular interval with deep brachial artery → runs between lateral and medial head of the tricep brachii → runs in the radial groove posteriorly → runs inferior to the deltoid tuberosity → pierces the lateral intermuscular septum → gives off branch to

anconeus muscle & posterior cutaneous nerve of the forearm

→ continues across the lateral epicondyle into anterior arm between brachialis and brachioradialis → emerges in elbow → gives off superficial (sensory for dorsum of hand) and deep (motor for posterior compartment of forearm) branches → continues to forearm

Cubital Fossa

shallow triangular depression anterior to the elbow joint that contains the tendon of biceps brachii, the brachial artery (bifurcates into ulnar and radial arteries at the inferior angle), & the median nerve.

Roof of cubital fossa

bicipital aponeurosis & antebrachial fascia

Floor of cubital fossa

brachialis and supinator muscles

base of cubital fossa

Imaginary line between medial and lateral epicondyles

medial border of cubital

pronator teres muscle

lateral border of cubital fossa

brachioradialis muscle

Superficial Structures of the cubital fossa

1. Bicipital aponeurosis

2. Superficial Veins of the arm

3. Lateral & medial cutaneous nerves of the forearm

veins bordering the cubital fossa

1. Basilic Vein

2. Cephalic Vein

3. Median Cubital Vein

muscles surrounding the cubital fossa

1. brachialis

2. supinator

3. brachioradialis

4. biceps brachii tendon

5. pronator teres

nerves bordering the cubital fossa

1. musculocutaneous nerve

2. radial nerve