Opponens pollicis muscle

Opponens pollicis muscle
The muscles of the thumb
The muscles of the left hand. Palmar surface.
Latin	musculus opponens pollicis
Gray's	subject #126 461
Origin	trapezium and transverse 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 first carpometacarpal joint, which aids in opposition of the thumb

The opponens pollicis is a small, triangular muscle in the hand, which functions to oppose the thumb. It is one of the three thenar muscles, lying deep to the abductor pollicis brevis and lateral to the flexor pollicis brevis.

Structure

The opponens pollicis originates from the flexor retinaculum of the hand and the tubercle of the trapezium. It passes downward and laterally, and is inserted into the whole length of the metacarpal bone of the thumb on its radial side.

Innervation

Like the other thenar muscles, the opponens pollicis is innervated by the recurrent branch of the median nerve.

Actions

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 opposition that this muscle is responsible for is the flexion of the thumb's metacarpal at the first carpometacarpal joint. This specific action cups the palm. Many texts, for simplicity, use the term opposition to represent this component of true opposition. In order to truly oppose the thumb, the actions of a number of other muscles are needed at the thumb's metacarpophalangeal joint.

Blood Supply

The opponens pollicis receives its blood supply from the Superficial palmar arch.

Additional images

• 

  Bones of the left hand. Volar surface.

• 

  Transverse section across the wrist and digits.

External links

• LUC op
• -1368719349 at GPnotebook
• SUNY Labs 08:st-0416
• opponens+pollicis+muscle at eMedicine Dictionary
• PTCentral

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.