Adductor pollicis
Adductor pollicis
- Latin synonym: Musculus adductor pollicis
- Synonym: Adductor pollicis muscle
Definition
Adductor pollicis | |||
Origin | Transverse head: anterior body of the third metacarpal. Oblique head: bases of the second and third metacarpals and the adjacent capitate bone | ||
Insertion | Medial side of the base of the proximal phalanx of the thumb and the ulnar sesamoid | ||
Innervation | Deep branch of ulnar nerve (T1) | ||
Action | Adducts the thumb at the carpometacarpal joint | ||
Antagonist | Abductor pollicis longus muscle, Abductor pollicis brevis muscle | ||
The adductor pollicis is a crucial, triangular-shaped intrinsic muscle of the hand, located deep to the flexor pollicis brevis. It's composed of two distinct heads: the oblique head and the transverse head.
Oblique Head
This head originates from the bases of the second and third metacarpals, the capitate bone, and nearby carpal ligaments.
Transverse Head
The transverse head arises from the palmar surface of the third metacarpal shaft.
Insertion
Both heads converge laterally. Their primary insertion is onto the ulnar sesamoid bone and the ulnar side of the base of the proximal phalanx of the thumb. Some fibers also contribute to the dorsal aponeurosis of the thumb.
Important relations
The adductor pollicis is larger and lies deeper than the other thenar muscles. On its anterior (ventral) surface, it's crossed by the flexor tendons of the index finger, the first lumbrical, and the flexor pollicis brevis. Posterior (dorsal) to it, the muscle is related to, and sometimes even fused with, the first dorsal interosseous muscle.
References
Okwumabua E, Sinkler MA, Bordoni B. Anatomy, Shoulder and Upper Limb, Hand Muscles. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537229/ Loss J
Li ZM. Biometry of thenar muscle origins on the flexor retinaculum. Clin Anat. 2020 Nov;33(8):1176-1180.
