Adductor pollicis

Adductor pollicis

The adductor pollicis is a muscle in the hand that plays a crucial role in the movement of the thumb. It is one of the intrinsic muscles of the hand and is responsible for the adduction of the thumb, which means it brings the thumb towards the palm and the fingers.

Anatomy

The adductor pollicis is a triangular muscle with two heads: the oblique head and the transverse head.

Oblique Head

The oblique head originates from the bases of the second and third metacarpal bones, the capitate bone, and the adjacent carpal bones. It inserts into the medial side of the base of the proximal phalanx of the thumb.

Transverse Head

The transverse head originates from the anterior surface of the third metacarpal bone and also inserts into the medial side of the base of the proximal phalanx of the thumb.

Innervation

The adductor pollicis is innervated by the ulnar nerve, specifically the deep branch of the ulnar nerve. This is in contrast to most of the other intrinsic muscles of the hand, which are typically innervated by the median nerve.

Function

The primary function of the adductor pollicis is to adduct the thumb. This action is essential for the grip and manipulation of objects, allowing for a strong and precise pinch. The muscle works in coordination with other muscles of the hand, such as the thenar muscles, to perform complex movements.

Blood Supply

The adductor pollicis receives its blood supply from the deep palmar arch, which is primarily formed by the radial artery and the ulnar artery.

Clinical Significance

Damage to the ulnar nerve can result in weakness or paralysis of the adductor pollicis, leading to difficulties in thumb adduction and grip strength. This condition is often assessed using the Froment's sign test.

Related Pages

• Hand
• Thumb
• Ulnar nerve
• Median nerve
• Thenar muscles
• Metacarpal bones
• Capitate bone
• Radial artery