Anatomy and Physiology

Upper Extremity

Deltoid

Action: Shoulder flexion, extension and ABDuction.

Trapezius

Action: Bilateral neck extension and unilateral scapular roation, retraction, and elevation.

Latissimus Dorsi

Action: Shoulder extension, ADDuction, and medial/internal rotation.

Levator Scapulae

Action: Scapular Elevation

Rhomboids Major & Minor

Actions: Scapular retraction and stabilizes scapula against thoracic cage

Rotator Cuff Muscles

Supraspinatus, Infraspinatus, Teres Minor, Subscapularis

Supraspinatus

Action: First 30 degrees of shoulder ABDuction

Infraspinatus

Action: Shoulder external/lateral rotation

Teres Minor

Action: Shoulder external/lateral rotation

Subscapularis

Action: Shoulder internal/ medial rotation

Teres Major

Actions: Shoulder extension internal/ medial rotation, and ADDuction

Biceps Brachii

Action: Elbow flexion; Forearm Supination

Brachialis

Action: Elbow flexion; forearm pronation

Brachioradialis

Action: Elbow flexion, slight wrist radial deviation

Triceps Brachii

Action: Elbow extension

Flexor Carpi Radialis

Actions: Wrist flexion and radial deviation

Flexor Carpi Ulnaris

Action: Wrist flexion and ulnar deviation

Flexor Digitorum Superficialis

Action: Wrist flexion; Flexion of proximal interphalangeal joints. Only through 2-5

Extensor Carpi Radialis

Action: Wrist extension and radial deviation

Extensor Carpi Ulnaris

Action: Wrist extension and ulnar deviation

Extensor Digitorum

Action: Wrist extension and extension of interphalangeal joints of the second through fifth phalanges