ORIGIN

Middle anterior surface of the radius and the interosseous membrane. The muscle may also originate from the lateral border of the coronoid process of the ulna or the medial epicondyle of the humerus

 

INSERTION

Palmar aspect of the base of the distal phalanx of thumb

 

ACTION

Extension of the thumb at the carpometacarpal, metacarpophalangeal, and interphalangeal joints

Extension of wrist

Abduction of the wrist

Weak supination of the forearm from a pronated position

 

INNERVATION

Interosseous branch of the median nerve (C8, T1)

 

PRIMARY JOINT

Wrist joint

 

KEY STRENGTH TRAINING EXERCISES

Lateral raises with dumbbells

 

NEW STRENGTH TRAINING EXERCISES

Wrist extensor stretch

Wrist extension with resistance bands

 

COMMON INJURIES

Overuse

Straining/stiffness

Tear