| Opponens pollicis muscle | |
|---|---|
 The deep muscles of the right hand. Palmar surface. | |
 The superficial muscles of the left hand. Palmar surface. | |
| Details | |
| Origin | Trapezium andtransverse carpal ligament |
| Insertion | Metacarpal bone of the thumb on its radial side |
| Artery | Superficial palmar arch |
| Nerve | Recurrent branch of the median nerve |
| Actions | Flexion of the thumb's metacarpal at the firstcarpometacarpal joint, which aids inopposition of the thumb |
| Identifiers | |
| Latin | musculus opponens pollicis |
| TA98 | A04.6.02.058 |
| TA2 | 2525 |
| FMA | 37379 |
| Anatomical terms of muscle | |
Theopponens pollicis is a small, triangular muscle in the hand, which functions to oppose the thumb. It is one of the threethenar muscles. It lies deep to theabductor pollicis brevis and lateral to theflexor pollicis brevis.
The opponens pollicis muscle is one of the threethenar muscles.[1] It originates from theflexor retinaculum of the hand and the tubercle of thetrapezium. It passes downward and laterally, and is inserted into the whole length of themetacarpal bone of the thumb on its radial side.
Like the other thenar muscles, the opponens pollicis is innervated by therecurrent branch of the median nerve.[2] In 20% of the population, opponens pollicis is innervated by theulnar nerve.[3]
The opponens pollicis receives its blood supply from thesuperficial palmar arch.
Opposition of the thumb is a combination of actions that allows the tip of the thumb to touch the tips of other fingers. The part of apposition that this muscle is responsible for is the flexion of the thumb's metacarpal at the firstcarpometacarpal joint. This specific action cups the palm. Many texts, for simplicity, use the termopposition to represent this component of true apposition. In order to truly appose the thumb, the actions of a number of other muscles are needed at the thumb'smetacarpophalangeal joint. Note that the two opponens muscles (opponens pollicis and opponens digiti minimi) are named so because they oppose each other, but their actions appose the bones.
This article incorporates text in thepublic domain frompage 461 of the 20th edition ofGray's Anatomy(1918)
