Upper limb

Palmaris Longus

Musculus palmaris longus

Origin

Medial epicondyle of the humerus (common flexor origin)

Insertion

Palmar aponeurosis and flexor retinaculum (fascial insertion, shown here at the level of the pisiform bone)

Function

Tenses the palmar aponeurosis; weak wrist flexor

Innervation

Median nerve, C7–C8

Movement & chain

Of limited functional importance; the muscle is absent in about 10–15% of people without noticeable loss of grip strength.

Palpation

Clearly visible/palpable as the most central, thin tendon on the volar wrist when the thumb and little finger are pressed together with the wrist slightly flexed.

Clinical

Because its function is often redundant, it is frequently used as a tendon graft donor in reconstructive hand surgery.

Segmental innervation

Median nerve, C7–C8.

In clinical practice

A popular donor tendon for tendon reconstructions (for example thumb ligament injuries), precisely because its absence rarely causes loss of function.

Region in the model

Upper limb