Opponens pollicis muscle

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Musculusopponenspollicis

Dissection of hand

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Opponens Pollicis is a small, triangular muscle in the hand that plays a crucial role in the movement and control of the thumb. It is one of the three thenar muscles, along with the abductor pollicis brevis and flexor pollicis brevis, that are primarily responsible for the fine motor movements of the thumb. The opponens pollicis enables the thumb to oppose, or move across the palm, a movement that is essential for grasping and manipulating objects.

Anatomy

The opponens pollicis originates from the flexor retinaculum and the tubercle of the trapezium bone in the wrist. It inserts into the entire length of the radial side of the metacarpal bone of the thumb. This muscle is innervated by the median nerve, specifically through its recurrent branch. The blood supply to the opponens pollicis comes from the superficial palmar arterial arch.

Function

The primary function of the opponens pollicis is to facilitate the opposition of the thumb, a movement that involves bringing the thumb across the palm to touch or come near the tips of the other fingers. This action is fundamental to many hand functions, including gripping, holding, and manipulating objects of various sizes and shapes. Without the opponens pollicis, the ability to perform these tasks would be significantly impaired.

Clinical Significance

Injury or nerve damage affecting the opponens pollicis can lead to a condition known as opponens pollicis weakness or paralysis, which can significantly impair hand function. One common cause of such damage is carpal tunnel syndrome, where the median nerve is compressed at the wrist, affecting the muscle's ability to function properly. Treatment for opponens pollicis muscle dysfunction typically involves physical therapy, splinting, or, in severe cases, surgery to relieve pressure on the median nerve.

See Also

• Thenar eminence
• Hand anatomy
• Carpal tunnel syndrome
• Median nerve