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The Flexor Pollicis Longus is in the Deep Layer of the Anterior Forearm Compartment.
The Flexor Pollicis Longus has two heads: Radial Head and Humeroulnar Head.
- Anterior radius to the thumb
- Flexes the thumb at the carpometacarpal, metacarpophalangeal, and proximal and distal interphalangeal joints.
- Flexes the hand at the wrist joint.
- Flexes the forearm at the elbow joint.
- Pronates the forearm at the radioulnar joints.
- The distal tendon of the flexor pollicis longus runs through the carpal tunnel and can be involved with carpal tunnel syndrome.
- The humeroulnar head is often extremely small or missing entirely.