Extensor group Forearm Muscles

what are the two layers of the extensor group ?

superficial, deep

how many extensor superficial group muscles?

6

Brachioradialis Purposeful Activity

Hammering a nail, playing drums

Brachioradialis action

Elbow flexion: weak, maximal when forearm is in midpronated position

Brachioradialis origin

Proximal two thirds of lateral supracondylar ridge of humerus

Brachioradialis insertion

Lateral surface of distal end of radius proximal to styloid process

Brachioradialis innervation

Radial nerve (C5, C6, C7)

Extensor Carpi Radialis Longus purposeful activity

Playing pickleball or table tennis, painting wall, stabilizing wrist for strong grasp

Extensor Carpi Radialis Longus action

Wrist extension and abduction (radial deviation) Carpometacarpal joint extension

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 innervation

Radial nerve (C6, C7)

Extensor Carpi Radialis Brevis purposeful activity

Playing pickleball or table tennis, painting wall, stabilizing wrist for strong grasp

Extensor Carpi Radialis Brevis Action

Wrist extension and abduction (radial deviation) Carpometacarpal joint extension Active during fist clenching

Extensor Carpi Radialis Brevis origin

Lateral epicondyle of humerus (common extensor tendon)

Extensor Carpi Radialis Brevis insertion

Dorsal aspect of base of 3rd metacarpal

Extensor Carpi Radialis Brevis innervation

Deep branch of radial nerve (C7, C8)

Extensor Digitorum purposeful activity

Typing, swiping up on smartphone

Extensor Digitorum action

• Wrist extension

• Carpometacarpal joints extension

• Extends medial four fingers primarily at metacarpophalangeal joints, secondarily at interphalangeal joint

Extensor Digitorum origin

Lateral epicondyle of humerus (common extensor tendon)

Extensor Digitorum insertion

Extensor expansions of medial four fingers

Extensor Digitorum innervation

Posterior interosseous nerve, from radial nerve (C7, C8)

Extensor Digiti Minimi purposeful activity

Drinking tea, “Horns Up”

Extensor Digiti Minimi Action

5th digit extension: primarily at metacarpophalangeal joint, secondarily at interphalangeal joint

Extensor Digiti Minimi origin

Lateral epicondyle of humerus (common extensor tendon)

Extensor Digiti Minimi insertion

Extensor expansion of 5th finger

Extensor Digiti Minimi innervation

Posterior interosseous nerve, from radial nerve (C7, C8)