BACK OF FOREARM 1

SUPPERFICIAL LAYER

•Origin: (common extensor origin)

•Front of lateral epicondyle of humerus

•Brachioradialis

Insertion:

•base of styloid process of radius.

Action:

•Accessory flexor of elbow joint when forearm is mid-pronated.

•Extensor carpi radialis longus

Insertion :

•Dorsal surface of base of metacarpal 2

Action :

extends and abducts the wrist

•Extensor carpi radialis brevis

Insertion

•Dorsal surface of base of metacarpal 3.

Action:

•Extends and abducts the wrist.

Nerve supply:

•Deep branch of radial nerve.

•Extensor digitorum

Insertion:

four tendons into the dorsal aspects of the bases of the  middle and distal phalanges of  the (medial 4 fingers).

Action:

•Extends the proximal & distal inter -  phalangeal joints of the (medial 4  fingers), metacapo - phalangeal  joints and also extends the wrist.

The  expansion is the  tendons of extensor digitorum. Fibrous sheath that encloses several tendons that pass across the metatarsophalangeal joints

The  expansion is the  tendons of extensor digitorum. Fibrous sheath that encloses several tendons that pass across the metatarsophalangeal joints

•Extensor digiti minimi

Insertion:

•Extensor expansion of the little finger

Action:

•Extends the proximal & distal inter -  phalangeal joints of the little finger; metacapo - phalangeal  joints and also extends the wrist.

•Extensor carpi ulnaris

Insertion:

•The DORSAL base of the metacarpal 5

Action:

Extends and adducts the wrist

•Anconeous

Origin:

Posterior surface of lateral epicondyle of humerus

Insertion

•Olecrenon & upper posterior surface of ulna

Action:

•Extension of the elbow joint.