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.
