Muscles Of The Posterior (Extensor) Compartment Of The Forearm

Front 1

Brachioradialis

Back 1

Function: Weak flexion of forearm, maximal when forearm is in midpronated position
Innervation: Radial nerve

Front 2

Extensor carpi radialis longus

Back 2

Function: Extend and abduct hand at wrist joint
Innervation: Radial nerve

Front 3

Extensor carpi radialis brevis

Back 3

Function: Extend and abduct hand at wrist joint
Innervation: Deep branch of radial nerve

Front 4

Extensor digitorum

Back 4

Function: extends digits 2-5 primarily at MP joints, secondarily at IP joints
Innervation: Posterior interosseous nerve, continuation of deep branch of radial nerve

Front 5

Extensor digiti minimi

Back 5

Function: extends digit 5 primarily at MP joint, secondarily at IP joint
Innervation: Posterior interosseous nerve, continuation of deep branch of radial nerve

Front 6

Extensor carpi ulnaris

Back 6

Function: extends and adducts hand at wrist joint
Innervation: Posterior interosseous nerve, continuation of deep branch of radial nerve

Front 7

Supinator

Back 7

Function: supinates forearm
Innervation: Deep branch of radial nerve

Front 8

Abductor pollicis longus (Snuff Box)

Back 8

Function: abducts thumb and extends it at carpometacarpal joint
Innervation: Posterior interosseous nerve, continuation of deep branch of radial nerve

Front 9

Extensor pollicis longus (Snuff Box)

Back 9

Function: extends distal phalanx of thumb at IP joint; extends MP and caropmetacarpal joints
Innervation: Posterior interosseous nerve, continuation of deep branch of radial nerve

Front 10

Extensor pollicis brevis (Snuff Box)

Back 10

Function: extends proximal phalanx of thumb at MP joint; extends carpometacarpal joint
Innervation: Posterior interosseous nerve, continuation of deep branch of radial nerve

Front 11

Extensor indicis

Back 11

Function: extends digit 2; helps extend hand at wrist
Innervation: Posterior interosseous nerve, continuation of deep branch of radial nerve