Question #97

Considering flexor digitorum profundus, which of the following statements is correct?

It runs over the flexor retinaculum

It arises from the common flexor origin

Damage to this muscle may result in a mallet finger

The median nerve lies between its tendons

It is a weak flexor of the wrist

Flexor digitorum profundus is one of the deep muscles of the anterior forearm. It arises from the anterior surface of the ulna, passes through the carpal tunnel and extends along the anterior surface of the phalanges, between the decussating fibres of flexor digitorum superficialis, and inserts into the terminal phalanges of the four fingers.

It is therefore the only muscle which can flex the distal interphalangeal joint of the fingers.

If extensor digitorum communis is damaged the unopposed action of flexor digitorum profundus at the distal interphalangeal joint would result in a mallet finger deformity.

Its lateral half is innervated by the anterior interosseous branch of the median nerve, while its ulnar half is innervated by the ulnar nerve.

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