Elbow and Forearm: Function and Dysfunction

Cubital Fossa: Borders

Brachioradialis

Pronator teres

Cubital Fossa: Contains

biceps tendon

brachial artery

median nerve

Cubital tunnel: Borders

Olecranon process

Medial epicondyle

Cubital tunnel: Contains

ulnar nerve

Radial tunnel: Borders

humeroradial joint

supinator

Radial tunnel: Contains

radial nerve

Radial head and Neck fractures: Mechanism of injury

FOOSH

often combined with elbow dislocation

What is stabilizing structures of the elbow/forearm may be injured?

annular ligament

lateral collateral ligament

Lateral (radial) collateral ligament injury

traumatic stress to elbow with hyperextension or rotation

FOOSH can → excessive elbow varus force → ?

lateral (radial) collateral ligament injury

Medial (ulnar) collateral ligament injury

repetitive throwing injuries

valgus stress to elbow (medial)

FOOSH can → Excessive Elbow Valgus Force →

medial (ulnar) collateral ligament injury

Bone + connective tissue injuries often lead to

joint stiffness

Proximal biceps ruptures

later in life/repetitive overhead use

attritional rupture of the proximal insertion of the long head of the biceps on the supraglenoid tubercle of the scapula

Proximal biceps ruptures: Mechanism of injury

degenerative changes of the proximal biceps tendon (wears down)

Distal Biceps Rupture

traumatic rupture of biceps tendon at its distal insertion on the bicipital/radial tuberosity of the radius

Distal Biceps Rupture: Mechanism of injury

forceful, often eccentric contraction of the biceps with the forearm in supination

Cubital tunnel syndrome

older individuals/repetitive positioning

compression of the ulnar nerve within the cubital tunnel

Cubital tunnel syndrome: Mechanism of injury

injury to medial elbow

prolonged positioning in elbow flexion greater than 90 degrees

prolonged positioning of elbow resting on a hard surface

Cubital tunnel syndrome: Symptoms

pain/paresthesia along ulnar nerve distribution

weakness with pinch and grasp activities

muscle atrophy of ulnar nerve-innervated mucles

sensory loss along ulnar nerve distribution

What is a synergistic muscle action goal?

increase force potential

stabilize proximal joints

How does the scapulothoracic joint and glenohumeral joint position affect the biceps brachii muscle activation?

biceps elbow flexion force potential increased with ST retraction and GH extension

How does forearm joint position affect biceps brachii muscle activation?

biceps selectively recruited when elbow flexion is combined with forearm supination

Biceps and triceps co-contract to stablize?

the elbow when forceful or controlled motions of the forearm, wrist, and/or hand are needed