Definition
By: Gregory R. Waryasz, MD
The adductor pollicis muscle of the musculoskeletal system is characterized by its oblique and transverse head.
It is part of the thenar muscles. It consists of skeletal muscle fibers.
Its unique structural features include its fan shape. It is deep in the palm of the adductor compartment of the hand. There are two origins making the oblique and the transverse head. The tendon component of the muscle usually contains a sesamoid bone.
The origin of the oblique head is the bases of the 2nd and 3rd metacarpals, capitates, and adjacent carpals. The transverse head has its origin on the anterior surface of the shaft of the 3rd metacarpal.
The insertion is the medial side of the base of the proximal phalanx of the thumb.
The blood supply is from the arteries of the palmar arches and venous drainage is from the accompanying veins.
The innervation is from the deep branch of the ulnar nerve.
The adductor pollicis muscle as well as all other bones, muscles, and ligaments of the body are derived of mesodermal origin in the embryo.
The function of the adductor pollicis is to adduct the thumb toward the lateral border of the palm. The synergists are the flexor pollicis brevis, flexor pollicis longus, and the opponens pollicis.
Common diseases include ulnar nerve palsy.
Ulnar nerve palsy can occur at any point of the course of the ulnar nerve leading to weakness and sensory changes. Numbness and tingling can occur in the distribution of the ulnar nerve.
Commonly used diagnostic procedures include clinical history, physical exam, EMG, and MRI.
It is usually treated with bracing, NSAIDs, physical therapy, and corticosteroid injections for ulnar nerve palsy syndrome.
References
Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.
Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Wheeless? Textbook of Orthopaedics: Adductor Pollicis (http://www.wheelessonline.com/ortho/adductor_pollicis)