Joint Positions in Anatomy

Elevates, depresses, retracts, and rotates the scapula (shoulder blade).

Extends, adducts, and medially rotates the arm at the shoulder.

Elevates the scapula (shoulder blade).

Retracts and rotates the scapula (shoulder blade).

Spinous processes of C7-T12 vertebrae, parts of the skull, and the nuchal ligament.

Lower six thoracic vertebrae, thoracolumbar fascia, iliac crest, and lower ribs.

Posterior tubercles of the first four cervical vertebrae.

Spinous processes of the upper part of the thoracic spine (minor) and lower cervical spine (major).

Medial epicondyle of the humerus (common flexor origin)

Base of 2nd metacarpal

Medial epicondyle (common flexor origin) and coronoid process

Bases of distal phalanges of 4th and 5th digits

Anterior interosseous nerve, from median nerve (C8, T1)

Pisiform, hook of hamate, 5th metacarpal

Ulnar nerve (C8, T1)

Olecranon and posterior border of ulna (via aponeurosis)

Pronates the forearm (rotates the palm downward) and helps bind the radius and ulna together.

It arises from the posterior surface of the proximal halves of the ulna, radius, and interosseous membrane.

Extends the thumb's distal phalanx (fingertip) at the interphalangeal joint, and also extends the metacarpophalangeal and carpometacarpal joints.

It attaches proximally to the posterior surface of the distal third of the radius and interosseous membrane, and distally to the dorsal aspect of the base of the thumb's proximal phalanx.

Flexes the forearm, especially when the forearm is in a mid-pronated position.

Proximally, it attaches to the lateral supraepicondylar ridge of the humerus. Distally, it attaches to the dorsal aspect of the base of the 2nd metacarpal.

This compartment includes the superficial layer of muscles located on the back (posterior) side of the forearm.

Extends and abducts (moves away from the midline) the hand at the wrist joint, and it's active during fist clenching.

Extensor Carpi Radialis Brevis

Proximal: Lateral epicondyle of humerus; Distal: Dorsal aspect of base of 3rd metacarpal

Extends the medial four digits primarily at metacarpophalangeal joints, secondarily at interphalangeal joints.

Extends the 5th digit (pinky finger) primarily at the metacarpophalangeal joint, secondarily at the interphalangeal joints.

Extensor Digiti Minimi

Extends and adducts the hand at the wrist joint, is active during fist clenching.

Proximal: Lateral epicondyle of humerus; Distal: Dorsal aspect of base of 5th metacarpal

Extends the 2nd digit, helps extend the hand at the wrist.

Adducts the thumb towards the lateral border of the palm, bringing it closer to the other fingers.

Located on the palmar side of the hand, connected to the tendons of the flexor digitorum profundus muscle.

Abduct the 2nd-4th fingers away from the middle finger (axial line), and also help flex the metacarpophalangeal joint and extend the interphalangeal joints.

Adduct the 2nd, 4th and 5th fingers towards the middle finger (axial line), and assist the lumbricals in flexing and extending the finger joints.

All dorsal and palmar interossei are innervated by the deep branch of the ulnar nerve (C8, T1).

Extends the index finger, helping to straighten it out.

The posterior interosseous nerve, a branch of the radial nerve, controls this muscle.

Opposes the thumb, bringing it towards the little finger, enabling gripping.

Moves the thumb away from the palm, towards the side of the hand.

Bends the thumb towards the palm.

Moves the little finger away from the palm, towards the side of the hand.

Bends the little finger towards the palm.

Opposes the little finger, bringing it towards the thumb, aiding in gripping.