Courtesy: Prof Nabile Ebraheim, University of Toledo, Ohio, USA
Adductor pollicis muscle
It is a small muscle of the hand and that is a very important muscle.
Anatomy of the muscle
Origin
2 heads :
1. Transverse head- arises from the radial surface of the body of 3rd metacarpal
2. Oblique head- arises from the second and third metacarpals. Also arises from capitate bone and adjacent carpals.
Insertion:
- 2 heads converge into a tendon and inserts along with the fibers of flexor pollicis brevis into the medial side(ulnar aspect at the base of proximal phalanx)of the thumb.
- There is a sesamoid bone passing in the tendon.
- The tendon inserts into the ulnar sesamoid bone of the thumb.
- It also inserts into the dorsal apparatus.
Function
- The predominant action of the adductor pollicis is adduction of the thumb metacarpal.
- It draws the first metacarpal laterally to oppose the thumb towards the center of the palm and rotate it medially.
- The adductor pollicis also works on the interphalangeal joint(ip)causing extension of that joint.
- It also works on the metacarpophalangeal joint (mcp) causing flexion of that joint.
- Action of the adductor pollicis muscle is complicated:
1. First metacarpal adduction
2. MCP flexion
3. IP extension
INNERVATION
- Deep branch of ulnar nerve(C8,T1)
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