Superficial Posterior Forearm

Question 1

Brachioradialis

Answer 1

Origin: Lateral supracondylar ridge of humerus, lateral intermuscular septum of arm
Insertion: Styloid process of radius
Action: Elbow flexion
Innervation: Radial nerve

Question 2

Extensor carpi radialis longus

Answer 2

Origin: Lateral supracondylar ridge of humerus, lateral intermuscular septum of arm
Insertion: Posterior aspect of base of metacarpal bone 2
Action: Hand extension, hand abduction
Innervation: Radial nerve

Question 3

Extensor carpi radialis brevis

Answer 3

Origin: Lateral epicondyle of humerus (common extensor tendon)
Insertion: Posterior aspect of base of metacarpal bone 3
Action: Hand extension, hand abduction
Innervation: Deep branch of radial nerve & posterior interosseous n.

Question 4

Extensor digitorum

Answer 4

Origin: Lateral epicondyle of humerus (common extensor tendon)
Insertion: Dorsal aspects of bases of both middle and distal phalanges of digits 2-5
Action: Metacarpophalangeal / Interphalangeal joints 2-5: Finger extension
Innervation: Posterior interosseous nerve

Question 5

Extensor digiti minimi

Answer 5

Origin: Lateral epicondyle of humerus (common extensor tendon)
Insertion: Extensor expansion of digit 5
Action: Metacarpophalangeal joint 5: Finger extension
Innervation: Posterior interosseous nerve

Question 6

Extensor carpi ulnaris

Answer 6

Origin: Lateral epicondyle of humerus, posterior border of ulna
Insertion: Base of metacarpal bone 5
Action: Hand extension and adduction
Innervation: Posterior interosseous nerve

Question 7

Anconeus

Answer 7

Origin: Lateral epicondyle of humerus
Insertion: Lateral surface of olecranon
Action:
Assists in forearm extension at the elbow joint;
Stabilization of elbow joint
Innervation: Radial nerve