Palmaris muscle

The palmaris muscle is a muscle of the forearm that is often absent in some individuals. It is a slender, fusiform muscle, and is one of the superficial flexors of the forearm.

Anatomy

The palmaris muscle originates from the medial epicondyle of the humerus as part of the common flexor tendon. It inserts into the palmar aponeurosis and the flexor retinaculum of the hand.

Innervation

The muscle is innervated by the median nerve, which is responsible for its motor function.

Blood Supply

The blood supply to the palmaris muscle is provided by the ulnar artery.

Function

The primary function of the palmaris muscle is to flex the hand at the wrist joint. It also tenses the palmar aponeurosis, which is important for gripping.

Clinical Significance

The palmaris muscle is absent in about 10-15% of the population. Its absence does not usually affect grip strength or wrist function. The tendon of the palmaris muscle is often used in tendon graft surgeries, such as Tommy John surgery.

Variations

There are several anatomical variations of the palmaris muscle. It may be completely absent, or it may have a different origin or insertion. In some cases, it may be duplicated or have an accessory muscle.

See also

• Flexor carpi radialis
• Flexor carpi ulnaris
• Extensor carpi radialis longus
• Extensor carpi radialis brevis

References

• Gray's Anatomy
• Clinical Anatomy by Regions