Muscle
Opponens pollicis
Turns the thumb pad toward the fingertips
High-yield
Opposition includes rotation at the thumb base. Opponens pollicis receives its usual motor supply from the recurrent median nerve branch.
Overview
This deep thenar muscle pulls on the first metacarpal, bringing it across the palm and rotating it. That movement positions the thumb pad to face the fingers during opposition.
Reference facts
- Origin
- Trapezium tubercle and flexor retinaculum
- Insertion
- Radial side of the first metacarpal shaft
- Action
- Moves and rotates the first metacarpal into thumb opposition
- Innervation
- Recurrent median nerve branch, mainly C8–T1
- Blood supply
- Radial artery, through its superficial palmar branch
Clinical correlation
Injury to the recurrent median branch can weaken thumb opposition and cause thenar wasting. These motor changes reflect loss of thenar muscle function, rather than a problem with thumb sensation alone.
Frequently asked questions
What does the opponens pollicis do?
The opponens pollicis moves and rotates the first metacarpal into thumb opposition.
What nerve innervates the opponens pollicis?
The opponens pollicis is innervated by the recurrent median nerve branch, mainly C8–T1.
Where does the opponens pollicis attach?
The opponens pollicis originates from the trapezium tubercle and flexor retinaculum and inserts on the radial side of the first metacarpal shaft.
What is the blood supply of the opponens pollicis?
The opponens pollicis is supplied by the radial artery, through its superficial palmar branch.