Lumbricals of the hand

Lumbricals of the Hand

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Lumbricals of the hand

The Lumbricals of the hand are four small skeletal muscles found in the human hand. They are part of the intrinsic muscle group, which also includes the interossei and the thenar and hypothenar muscles. The lumbricals are unique in that they originate from tendons, a characteristic not found in any other muscle group.

Anatomy

The lumbricals originate from the tendons of the Flexor digitorum profundus muscle. The first and second lumbricals are unipennate, originating from the radial side of the tendon, while the third and fourth are bipennate, originating from both the radial and ulnar sides.

Function

The primary function of the lumbricals is to flex the metacarpophalangeal joints and extend the interphalangeal joints. This allows for intricate movements such as the ability to hold a piece of paper between the thumb and index finger.

Clinical Significance

Damage to the lumbricals can result in a condition known as claw hand. This is characterized by hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints.

See Also

• Hand anatomy
• Flexor digitorum profundus
• Claw hand