Palmar interossei

Palmar Interossei are a group of three muscles found in the human hand. They are part of the intrinsic muscles of the hand, which are located within the hand itself, as opposed to the extrinsic muscles, which are located in the forearm. The palmar interossei are located on the palmar (or inner) side of the hand, and are responsible for the adduction of the fingers, or bringing the fingers together.

Anatomy

The palmar interossei originate from the sides of the metacarpal bones, which are the long bones in the hand that connect the fingers to the wrist. Each muscle inserts into the base of the corresponding finger's proximal phalanx and extensor expansion, which is a complex of tendons that extend the fingers.

The palmar interossei are unipennate, meaning they have fibers on one side of the tendon only. They are located on the medial side of the metacarpal bone in the case of the first and second palmar interossei, and on the lateral side in the case of the third palmar interosseous.

Function

The primary function of the palmar interossei is to adduct the fingers, or bring them together. They also assist in the flexion of the fingers at the metacarpophalangeal joints and extension at the interphalangeal joints. This allows for complex movements and dexterity in the human hand.

Clinical Significance

Damage or injury to the palmar interossei can result in a loss of finger adduction and reduced hand dexterity. This can be caused by a variety of conditions, including neuromuscular diseases, trauma, and repetitive strain injuries. Treatment typically involves physical therapy to restore function and strength to the hand.

See Also

• Dorsal interossei of the hand
• Hand anatomy
• Metacarpophalangeal joint
• Interphalangeal joints