There are two groups of muscles at
the back of forearm.
1. Superficial Muscle group
2. Deep Muscle group
There are seven muscles in the
superficial group.
1. Anconeus
2. Brachioradialis
3. Extensor carpi radialis longus
4. Extensor carpi radialis brevis
5. Extensor digitorum
6. Extensor digiti minimi
7. Extensor carpi ulnaris
Origin:
Lateral epicondyle of
humerus
Insertion:
Lateral and inferior to
olecranon process of ulna
Action:
1. Not a prime mover in any
joint action;
2. Assists in elbow extension
Nerve supply:
Radial nerve (C7, C8)
Origin:
Lateral supracondylar
ridge on the humerus
Insertion:
Styloid process of the
radius
Action:
Elbow flexion
Nerve supply:Radial nerve (C5, C6)
Origin:
Supracondylar ridge of
humerus
Insertion:
Base of second
metacarpal
Action:
1. Wrist extension
2. Radial deviation
Nerve supply:
Radial nerve (C6, C7)
Origin:
Lateral epicondyle of
humerus
Insertion:
Base of third
metacarpal
Action:
Wrist extension
Nerve supply:
Radial nerve
(C6, C7)
Origin:
Lateral epicondyle
of the humerus
Insertion:
Base of distal
phalanx of the second
through fifth fingers
Action:Extends all three joints of the
fingers (MCP, PIP, and DIP)
Nerve supply:Radial nerve (C6, C7, C8)
Origin:Lateral epicondyle of humerus
Insertion:Base of distal phalanx of fifth
finger
Action:Extends all three joints of fifth
finger (MCP, PIP, and DIP)
Nerve supply:Radial nerve (C6, C7, C8)
Origin:Lateral epicondyle of humerus
Insertion:Base of fifth metacarpal
Action:Wrist extension, ulnar deviation
Nerve supply:Radial nerve (C6, C7, C8)
There are 5 muscles in the deep muscle
group.
1. Supinator
2. Abductor pollicis longus
3. Extensor pollicis brevis
4. Extensor pollicis longus
5. Extensor indicis
Origin:Lateral epicondyle of
humerus and adjacent ulna
Insertion:Anterior surface of the
proximal radius
Action:Forearm supination
Nerve supply:Radial nerve (C6)
Origin:Posterior radius, interosseous
membrane, middle ulna
Insertion:Base of the first metacarpal
Action:Abducts thumb (CMC)
Nerve supply:Radial nerve (C6, C7)
Origin:Posterior distal radius
Insertion:Base of the proximal
phalanx of thumb
Action:Extends CMC and MCP
joints of thumb
Nerve supply:Radial nerve (C6, C7)
Origin:Middle posterior ulna and
interosseous membrane
Insertion:Base of distal phalanx of
thumb
Action:Extends all three joints of the
thumb (CMC, MCP, and IP)
Nerve supply:Radial nerve (C6, C7, C8)
Origin:Distal ulna
Insertion:Base of distal phalanx
of the second finger
Action:Extends all three joints of
the second finger (MCP, PIP, and
DIP)
Nerve supply:Radial nerve (C6, C7, C8)