Muscle
Adductor pollicis
Adducts the thumb (Froment sign)
High-yield
Ulnar-innervated thumb muscle; positive Froment sign (uses FPL to pinch) in ulnar palsy.
Overview
A deep two-headed muscle in the palm that adducts the thumb; its weakness underlies Froment's sign in ulnar nerve palsy.
Reference facts
- Origin
Oblique head: bases of 2nd–3rd metacarpals, capitate. Transverse head: anterior 3rd metacarpal
- Insertion
Medial base of the proximal phalanx of the thumb
- Action
Adducts the thumb toward the palm
- Innervation
Deep branch of the ulnar nerve (C8, T1)
- Blood supply
Deep palmar arch