Musculus palmaris longus

The palmaris longus is a muscle visible as a small tendon located between the flexor carpi radialis and the flexor carpi ulnaris, although it is not always present.

It is absent in about 14 percent of the population; however, this number can vary in African, Asian, and Native American populations.

Absence of the palmaris longus does not have an effect on grip strength.

However, the lack of palmaris longus muscle results in decreased pinch strength in fourth and fifth fingers in both sexes.

The absence of palmaris longus muscle is more prevalent in females than males.

The palmaris longus muscle can be seen by touching the pads of the fourth finger and thumb and flexing the wrist.

The tendon, if present, will be visible in the midline of the anterior wrist.