Pinpoint
Muscles/Forearm

Forearm

extensor pollicis longus

ek-STEN-sor POL-ih-sis LON-gus

Running deep in the forearm, the extensor pollicis longus straightens the thumb's end joint and adducts it. It's crucial for power grips in deadlifts and pinch strength. Athletes train it for thumb endurance in prolonged holds.

Open in 3D Viewer

Common Pain & Injury

Pain along the thumb or dorsal wrist, with possible EPL rupture causing thumb drop. Overuse in manual labor or sports. Doctor if sudden weakness or deformity.

Anatomy & Function

Origin

Middle third of the posterior surface of the ulna (medial forearm bone) and interosseous membrane.

Insertion

Dorsal aspect of the base of the distal phalanx of the thumb (thumb tip).

Actions

  • Extension of the interphalangeal joint of the thumb (thumb tip straightening)
  • Adduction of the thumb (thumb toward palm)

Innervation

Posterior interosseous nerve (C7-C8).

Muscle Relationships

Antagonists

Flexor pollicis longus

Synergists

Extensor pollicis brevisExtensor indicis

Trigger Points

Trigger points in the distal forearm refer to the thumb IP joint and dorsal hand.

Stretches

1Thumb IP extension stretch
2Prayer stretch variation

Common Conditions

Extensor pollicis longus ruptureRheumatoid tendonitis

Anatomical Parts

Right extensor pollicis longusLeft extensor pollicis longus

FAQ

Extensor pollicis longus rupture symptoms?

Sudden thumb extension loss with pain; common post-wrist fracture.

EPL muscle function?

Extends thumb tip and adducts it for strong pinching.

Extensor pollicis longus pain relief?

Rest, thumb spica splint, and anti-inflammatories.

Exercises for extensor pollicis longus

20

Also Works extensor pollicis longus

10

Related Forearm Muscles

Forearm Pain Guide

Common causes and relief

Activities & Sports

See which activities use extensor pollicis longus

Pinpoint·Interactive 3D Anatomy & Exercise Guide