Anatomy of Joint Positions

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

Extends, adducts, and medially rotates the humerus (upper arm bone).

Raises the scapula (shoulder blade) and rotates it.

Upper neck and back (superior nuchal line, spinous processes).

Back of the upper arm bone (humerus).

The Rhomboid muscles (minor and major) attach to the spine and the shoulder blade, near the spinal column.

Controlled by the spinal accessory nerve and some spinal nerves for sensory feedback.

Controlled by the thoracodorsal nerve.

Supraspinous fossa of scapula.

Laterally rotates the arm.

Axillary nerve (C5, C6).

Tip of coracoid process of scapula.

Helps flex and adduct the arm, resists shoulder dislocation.

Coronoid process and tuberosity of ulna.

Infraglenoid tubercle of scapula.

Median nerve (C6, C7).

Adducts and Medially rotates the arm.

Subscapular fossa of scapula (anterior surface).

Lateral epicondyle of humerus (common extensor origin)

Dorsal aspect of base of 3rd metacarpal

Extensor Digitorum

Lateral epicondyle of humerus; posterior border of ulna via a shared aponeurosis

Extensor expansion of 5th digit

Extends and adducts hand at wrist joint (also active during fist clenching)

Lateral, posterior, and anterior surfaces of proximal third of radius

Extends 2nd digit (enabling its independent extension); helps extend hand at wrist.

Pronates the forearm (turns palm down) and helps bind the radius and ulna together.

Abducts (moves away from midline) and extends (straightens) the thumb at the carpometacarpal joint.

Extends the distal phalanx (fingertip) of the thumb at the interphalangeal joint and also helps extend the thumb at other joints.

Extends the proximal phalanx (thumb's base) of the thumb at the metacarpophalangeal joint.

Weakly flexes the forearm (bends elbow) and is best at this when the forearm is slightly turned.

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

Distal quarter of anterior surface of ulna (proximal) and distal quarter of anterior surface of radius (distal).

Posterior surface of middle third of ulna and interosseous membrane (proximal) and dorsal aspect of base of distal phalanx of thumb (distal).

The Palmaris Longus muscle helps flex the hand at the wrist and tense the palmar aponeurosis, which is a thick fibrous sheet that supports the palm.

The Flexor Carpi Ulnaris (FCU) muscle attaches to several bones in the wrist: the pisiform, the hook of the hamate, and the base of the 5th metacarpal.

This muscle flexes the middle phalanges at the PIP joints of the middle four fingers, and can also help flex the proximal phalanges at the MP joints.

The FDP muscle is innervated by the ulnar nerve, which also provides sensation to the pinky and part of the ring finger.

The FPL muscle flexes the distal phalanx of the thumb, allowing you to bend the tip of your thumb.

Extends the index finger; aids in supination of the forearm and rotation of the radius to turn the palm anteriorly (if elbow is flexed).

Innervated by the posterior interosseous nerve, which is a continuation of the deep branch of the radial nerve.

Opposes the thumb, drawing it medially and rotating it to bring it towards the palm.

Abducts the thumb, moving it away from the hand and helping with opposition.

Flexes the thumb, bringing it towards the palm.

Abducts the little finger, moving it away from the hand and helping with flexing its proximal phalanx.

Flexes the proximal phalanx of the little finger, bending it towards the palm.

Draws the little finger medially and rotates it, bringing it into opposition with the thumb.

A triangular space on the anterior elbow, containing vessels and nerves.

Superior: imaginary line between epicondyles. Medial: flexor muscles (pronator teres). Lateral: extensor muscles (brachioradialis).

Formed by the brachialis and supinator muscles.

Made of fascia, subcutaneous tissue, and skin.

Brachial artery, radial & ulnar arteries, biceps tendon, median nerve, radial nerve.