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

It is a slender, fusiform muscle, lying on the medial side of the Flexor carpi radialis.

It arises from the medial epicondyle of the humerus by the common tendon, from the intermuscular septa between it and the adjacent muscles, and from the antibrachial fascia.

It ends in a slender, flattened tendon, which passes over the upper part of the transverse carpal ligament, and is inserted into the central part of the transverse carpal ligament and lower part of the palmar aponeurosis, frequently sending a tendinous slip to the short muscles of the thumb.

Variations

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One of the most variable muscles in the body.

This muscle is often absent about (10 per cent.), and is subject to many variations; it may be tendinous above and muscular below; or it may be muscular in the center with a tendon above and below; or it may present two muscular bundles with a central tendon; or finally it may consist solely of a tendinous band.

The muscle may be double.

Slips of origin from the coronoid process or from the radius have been seen.

Partial or complete insertion into the fascia of the forearm, into the tendon of the Flexor carpi ulnaris and pisiform bone, into the navicular, and into the muscles of the little finger have been observed.

External links

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• PTCentral

Musculus palmaris longus