Extensor region of forearm

Anconeus - Origin

Lateral epicondyle of humerus

Anconeus - Insertion

Lateral surface of olecranon and superior part of posterior surface of ulna

Anconeus - Peripheral Innervation

Radial Nerve

Anconeus - Action

Assists triceps in extending elbow; stabilizes elbow joint; may abduct ulna during forearm pronation

Brachioradialis - Origin

Proximal (2/3) part of supracondylar ridge of humerus

Brachioradialis - Insertion

Distal lateral radius, proximal to styloid process

Brachioradialis - Peripheral Innervation

Radial Nerve

Brachioradialis - Segmental Innervation

C5, C6, C7

Brachioradialis - Action

Relatively weak flexor of elbow; maximal when forearm is in mid-pronation position

Extensor Carpi Radialis Longus - Origin

Lateral supracondylar ridge of humerus

Extensor Carpi Radialis Longus - Insertion

Dorsal aspect of base of 2nd metacarpal

Extensor Carpi Radialis Longus - Peripheral Innervation

Radial Nerve

Extensor Carpi Radialis Longus - Segmental Innervation

C6,C7

Extensor Carpi Radialis Longus - Action

Wrist extension and radial deviation

Extensor Carpi Radialis Brevis - Origin

Lateral epicondyle of humerus

Extensor Carpi Radialis Brevis - Insertion

Dorsal aspect of base of 3rd metacarpal

Extensor Carpi Radialis Brevis - Peripheral Innervation

Radial Nerve (deep branch)

Extensor Carpi Radialis Brevis - Segmental Innervation

C7, C8

Extensor Carpi Radialis Brevis - Action

Wrist extension and radial deviation

Extensor Digitorum - Origin

Lateral epicondyle of humerus

Extensor Digitorum - Insertion

Extensor expansion of digits 2-5

Extensor Digitorum - Peripheral Innervation

Radial Nerve (deep branch)

Extensor Digitorum - Segmental Innervation

C7, C8

Extensor Digitorum - Action

Extends digits 2-5 primarily at metacarpophalngeal joints, secondarily via the extensor mechanism at PIP and DIP joints

Extensor Digiti Minimi - Origin

Lateral epicondyle of humerus

Extensor Digiti Minimi - Insertion

Extensor expansion of 5th digit

Extensor Digiti Minimi - Peripheral Innervation

Radial Nerve (deep branch)

Extensor Digiti Minimi - Action

Extends 5th digit primarily at metacarpophalngeal joint, secondarily via the extensor mechanism at PIP and DIP joints

Extensor Carpi Ulnaris - Origin

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

Extensor Carpi Ulnaris - Insertion

Dorsal aspect of base of 5th metatarsal

Extensor Carpi Ulnaris - Peripheral Innervation

Radial Nerve (deep branch)

Extensor Carpi Ulnaris - Action

Wrist extension and ulnar deviation

Supinator - Origin

Lateral epicondyle of humerus; radial collateral and annular ligaments; supinator fossa; crest of ulna

Supinator - Insertion

Lateral, posterior, and anterior surfaces of proximal (1/3 of) radius

Supinator - Peripheral Innervation

Radial Nerve (deep branch)

Supinator - Segmental Innervation

C7, C8

Supinator - Action

Supinates forearm

Abductor Pollicis Longus - Origin

Posterior surface (of proximal halves) of ulna, radius, and interosseous membrane

Abductor Pollicis Longus - Insertion

base of 1st metacarpal

Abductor Pollicis Longus - Peripheral Innervation

Radial Nerve (posterior interosseous nerve)

Abductor Pollicis Longus - Action

1st CMC abduction and extension

Extensor Pollicis Brevis - Origin

Posterior surface of distal (1/3 of) radius and interosseous membrane

Extensor Pollicis Brevis - Insertion

dorsal aspect of base of 1st proximal phalanx

Extensor Pollicis Brevis - Peripheral Innervation

Radial Nerve (posterior interosseous nerve)

Extensor Pollicis Brevis - Action

1st CMC and MCP extension

Extensor Pollicis Longus - Origin

Posterior surface of middle (1/3 of) ulna and interosseous membrane

Extensor Pollicis Longus - Insertion

dorsal aspect of base of 1st distal phalanx

Extensor Pollicis Longus - Peripheral Innervation

Radial Nerve (posterior interosseous nerve)

Extensor Pollicis Longus - Action

Extension of 1st CMC, MCP, and IP joints (only extensor at IP joint)

Extensor Indicis - Origin

Posterior surface of distal (1/3 of) ulna and interosseous membrane

Extensor Indicis - Insertion

extensor expansion of 2nd digit

Extensor Indicis - Peripheral Innervation

Radial Nerve (posterior interosseous nerve)

Extensor Indicis - Action

Extends 2nd digit primarily at metacarpophalngeal joint, secondarily via extensor mechanism at PIP and DIP joints; weak wrist extension