Anatomy 9: Forearm Extensors & dorsum of hand

Colles Fracture

50 yrs old, more common in females (osteoporosis) Fall on an outstretched hand (extended, supinated, radially deviated) *Dinner fork deformity* Can be accompanied by avulsion of the ulnar styloid process

Abductor Pollicis Longus (APL) action

abducts thumb, extends at carpometacarpal joint

Radial n

all extensor muscles are innervated by branches of this

Abductor Pollicis Longus (APL) insertion

base of 1st metacarpal

Extensor Carpi Radialis Longus (ECRL) insertion

base of 2nd metacarpal

Extensor Pollicis Longus(EPL) (Deep Muscle) insertion

base of distal phalanx of the thumb

Extensor Pollicis Brevis (EPB) insertion

base of proximal phalanx of the thumb

Extensor Carpi Radialis Brevis (ECRB) insertion

base of the 3rd metacarpal

Abductor Pollicis Longus (APL) innervation

deep branch of radial n

Extensor Carpi Ulnaris (Superficial muscle) innervation

deep branch of radial nerve

Extensor Digiti Minimi (Superficial muscle) innervation

deep branch of radial nerve

Extensor Digitorum innervation

deep branch of radial nerve

Extensor Pollicis Brevis (EPB) innervation

deep branch of radial nerve

Extensor Pollicis Longus(EPL) (Deep Muscle) innervation

deep branch of radial nerve

Extensor indicis innervation

deep branch of radial nerve

Supinator (deep muscle) innervation

deep branch of radial nerve

Extensor Carpi Radialis Longus (ECRL) action

extends & abducts hand

Extensor Carpi Radialis Brevis (ECRB) action

extends and abducts hand extend and abduct wrist against the resistance

Extensor Pollicis Longus(EPL) (Deep Muscle) action

extends distal phalanx of the thumb

Extensor Pollicis Brevis (EPB) action

extends proximal phalanx of the thumb

Extensor Digitorum insertion

extensor expansions for medial four digits

Extensor Carpi Radialis Brevis (ECRB) origin

lateral epicondyle

Extensor Digitorum origin

lateral epicondyle of humerus (common extensor origin)

Extensor Carpi Radialis Longus (ECRL) origin

lateral supra-epicondylar ridge

Extensor Pollicis Brevis (EPB) origin

posterior surface of distal 1/3 of radius

Extensor Pollicis Longus(EPL) (Deep Muscle) origin

posterior surface of distal 1/3 of ulna

Abductor Pollicis Longus (APL) origin

posterior surface of proximal halves of ulna, radius, and interosseous membrane

Extensor Carpi Radialis Brevis (ECRB) innervation

radial n.

Extensor Carpi Radialis Longus (ECRL) innervation

radial n.