Extensor Pollicis Brevis (EPB)

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Figure 1: Muscles that move the Forearm¹

Mucous sheaths of the dorsal hand²

Transverse section of distal forearm²

Transverse cut of the Hand²

Reading list

• MMT³

Muscle	Origin	Insertion	Innervation	Action
Extensor pollicis brevis	Radius (posterior) IO membrane	Base of 1st proximal phalanx	Radial n. C7 - C8	Radiocarpal joint: Radial dev. 1st CMC & MCP: Extension

Origin

• Distal posterior Radius⁴
• IO membrane⁴

Insertion

Base 1st Metacarpal⁴

Innervation

Posterior Interosseous N. (C7, C8)⁴

Action

• Wrist: Extension, Radial deviation⁴
• Thumb: Extension⁴

Notes

1.

Betts JG, Blaker W. Anatomy and Physiology. 2nd ed. OpenStax; 2022. https://openstax.org/details/books/anatomy-and-physiology-2e/?Book%20details

2.

Gray H. Anatomy of the Human Body. 20th ed. (Lewis WH, ed.). Lea & Febiger; 1918. https://www.bartleby.com/107/

3.

Weinstock D. NeuroKinetic Therapy: An Innovative Approach to Manual Muscle Testing. North Atlantic Books; 2010.

4.

Gilroy AM, MacPherson BR, Wikenheiser JC, Voll MM, Wesker K, Schünke M, eds. Atlas of Anatomy. 4th ed. Thieme; 2020.