In regard to flexion of the thumb, only the flexor pollicis longus is located in the forearm. It lies beside the flexor profundus and is attached to the distal phalanx (digit) just as the flexor profundus.

Origin

It originates on the anterior surface of the middle half of the radius and adjacent parts of the interosseous membrane.

Insertion

Insertion is on the anterior surface of the base of the distal phalanx of the thumb.

Function

Flexes the fingers.

With the complexity of all of the muscles and actions in the fingers, some are important in sports and bodybuilding

Volume 13 - The Fingers and Hand of our Kinesiology of Exercise Ebooks is a first for a book on strength training for the fingers and hand.