Articulations and Muscles of the Upper Extremity

A comprehensive vocabulary review of anatomical actions, movements, and muscle groups of the shoulder, arm, and forearm.

Scapular Elevation

The upward movement of the scapula toward the head.

Scapular Depression

The downward movement of the scapula returning from an elevated position.

Scapular Retraction

Also termed adduction of the scapula; the movement of the scapulae medially toward the vertebral column.

Scapular Protraction

Also termed abduction of the scapula; the movement of the scapulae laterally away from the vertebral column.

Scapular Downward Rotation

The movement of the scapula returning it back to the anatomical position following upward rotation.

Shoulder Flexion

An anterior movement of the humerus at the shoulder joint spanning from $0^\bot$ to a normal maximum of $180^\bot$.

Shoulder Extension

A posterior movement of the humerus at the shoulder joint spanning from $0^\bot$ to a normal range of $60^\bot$.

Forearm Supination

Rotation of the forearm from the neutral position that directs the palm anteriorly or upward, with a normal range of $90^\bot$.

Forearm Pronation

Rotation of the forearm from the neutral position that directs the palm posteriorly or downward, with a normal range of $90^\bot$.

Radial Deviation

Lateral movement or abduction of the hand at the wrist joint toward the radial or thumb side.

Ulnar Deviation

Medial movement or adduction of the hand at the wrist joint toward the ulnar or pinky side.

Deltoid

A major shoulder muscle comprising anterior, medial (middle), and posterior fiber groups that performs shoulder flexion, extension, and abduction.

Anterior Deltoid

The anterior fiber division of the deltoid muscle responsible for shoulder flexion.

Medial Deltoid

The middle fiber division of the deltoid muscle responsible for shoulder abduction.

Posterior Deltoid

The posterior fiber division of the deltoid muscle responsible for shoulder extension.

Trapezius

A broad back muscle divided into superior, middle, and inferior sections that performs bilateral neck extension along with unilateral scapular rotation, retraction, and elevation.

Latissimus Dorsi

A large superficial back muscle that performs shoulder extension, adduction, and medial (internal) rotation.

Levator Scapulae

A posterior neck and shoulder girdle muscle whose primary action is scapular elevation.

Rhomboids Major & Minor

Deep shoulder girdle muscles that perform scapular retraction and stabilize the scapula against the thoracic cage.

Rotator Cuff Muscles

A group of four shoulder-stabilizing muscles abbreviated as SITS: Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis.

Supraspinatus

A rotator cuff muscle occupying the supraspinous fossa of the scapula that performs the first $30^\bot$ of shoulder abduction.

Infraspinatus

A rotator cuff muscle occupying the infraspinous fossa of the scapula that performs shoulder external (lateral) rotation.

Teres Minor

A rotator cuff muscle that performs shoulder external (lateral) rotation and adduction.

Subscapularis

A rotator cuff muscle that originates in the subscapular fossa, inserts on the lesser tuberosity of the humerus, and performs shoulder internal (medial) rotation.

Teres Major

A shoulder muscle that performs shoulder extension, internal (medial) rotation, and adduction.

Biceps Brachii

An anterior arm muscle whose actions are elbow flexion and forearm supination.

Brachialis

An anterior arm muscle that flexes the forearm at the elbow and contributes to slight forearm pronation.

Brachioradialis

A muscle spanning the elbow and forearm that performs elbow flexion and slight wrist radial deviation.

Triceps Brachii

A posterior arm muscle whose primary action is elbow extension.

Flexor Carpi Radialis

An anterior forearm muscle that performs wrist flexion and wrist radial deviation.

Flexor Carpi Ulnaris

An anterior forearm muscle that performs wrist flexion and wrist ulnar deviation.

Flexor Digitorum Superficialis

An anterior forearm muscle that performs wrist flexion and flexion of the proximal interphalangeal joints of digits $2$ through $5$.

Extensor Carpi Radialis (Longus and Brevis)

Posterior forearm extensor muscles that perform wrist extension and wrist radial deviation.

Extensor Carpi Ulnaris

A posterior forearm extensor muscle inserting at the base of metacarpal $5$ that performs wrist extension and wrist ulnar deviation.

Extensor Digitorum

A posterior forearm extensor muscle that performs wrist extension and extension of the interphalangeal joints of digits $2$ through $5$.