Palmaris muscle

Palmaris Longus

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The Palmaris Longus muscle, located in the forearm and wrist.

The Palmaris Longus is a thin, fusiform muscle in the human forearm. It is one of the five muscles of the superficial flexor group of the anterior compartment of the forearm.

Origin and Insertion

The Palmaris Longus originates from the medial epicondyle of the humerus and inserts into the flexor retinaculum of the hand and the palmar aponeurosis.

Function

The primary function of the Palmaris Longus is to tense the palmar aponeurosis, assisting in flexion of the wrist. It also plays a role in the opposition of the thumb.

Clinical Significance

The Palmaris Longus is often used as a source of tendon grafts, due to its long, easily accessible tendon and the fact that its absence or removal does not significantly affect wrist function.

Variations

The Palmaris Longus is known for its high degree of anatomical variation. It is absent in about 14% of the population, and may be duplicated, or present only unilaterally.

See Also

• Flexor carpi radialis
• Flexor carpi ulnaris
• Flexor digitorum superficialis
• Flexor digitorum profundus