Extensor Pollicis Longus

Original Editor - Uchechukwu Chukwuemeka

Top Contributors - Uchechukwu Chukwuemeka, Kim Jackson and Shaimaa Eldib

Description[edit | edit source]

Extensor pollicis longus.png

Extensor pollicis longus (EPL) is a long muscle located at the deep layer with extensor pollicis brevisabductor pollicis longusextensor indicis, and supinator muscle in the posterior compartment of the forearm.[1] It originates from the mid-third of the ulna, and interosseous membrane then courses down to the distal phalanx of the thumb. Though it is situated at the forearm, it is classified as part of the extrinsic muscles of the hand as it's function is seen in thumb movement.[2] 

Origin[edit | edit source]

It originates from the mid-third of the ulna, and interosseous membrane

Insertion[edit | edit source]

It inserts at the base of distal phalanx of thumb via Lister's tubercle; that is the dorsal tubercle of the radius.

Nerve[edit | edit source]

It is innervated by the deep branch of the radial nerve via the posterior interosseous nerve (7th and 8th cervical nerve root).[3]

Artery[edit | edit source]

EPL blood supply is via the posterior interosseous artery and perforating branches of the anterior interosseous artery.[4][5]

Function[edit | edit source]

  • The EPL mainly hyper-/extends the interphalangeal joint of the distal phalanx of the thumb.[6]
  • It also serves as accessory extensors and adductors of the metacarpophalangeal of the proximal phalanx and carpometacarpal joints of the first metacarpal.[5]
  • It may also assist in wrist joint extension.[4]


Clinical relevance[edit | edit source]

Tenosynovitis is a relatively common inflammatory irritation of the synovial sheath, after repetitive activities such as playing drum; this is termed drummers palsy.[4]

Assessment[edit | edit source]


References[edit | edit source]

  1. Moore KL, Dalley AF, Agur AM. Clinically oriented anatomy. 7th ed. Baltimore, MD: Lippincott Williams & Wilkins, 2014.
  2. Drake RL, Vogl W, Mitchell AW, Gray H. Gray's anatomy for Students 2nd edition. Philadelphia : Churchill Livingstone/Elsevier, 2010.
  3. Department of Radiology; University of Washington. Available from: https://rad.washington.edu/muscle-atlas/extensor-pollicis-longus/ (accessed 10 October 2020)
  4. 4.0 4.1 4.2 KenHub. Available from:https://www.kenhub.com/en/library/anatomy/extensor-pollicis-longus-muscle (accessed 10 October 2020)
  5. 5.0 5.1 Khan I. Anatomy, Shoulder and Upper Limb, Hand Extensor Pollicis Longus Muscle. In: Varacallo M. editor. Statpearls, 2020. Available from:https://www.statpearls.com/articlelibrary/viewarticle/36135/ (accessed 10 October 2020)
  6. Wikipedia. 2019. Available from:https://en.wikipedia.org/wiki/Extensor_pollicis_longus_muscle (accessed 10 October 2020)
  7. Nabil Ebraheim. Extensor Muscles of The Thumb - Everything You Need To Know - Dr. Nabil Ebraheim. Available from: http://www.youtube.com/watch?v=Wx2kew_ut_Y [last accessed 10/10/2020]
  8. Nabil Ebraheim. Rupture of the Extensor Pollicis Longus Tendon - Everything You Need To Know - Dr. Nabil Ebraheim. Available from: http://www.youtube.com/watch?v=QvDRgMR5_6E [last accessed 10/10/2020]
  9. Nabil Ebraheim. Common Conditions Of The Thumb - Everything You Need To Know - Dr. Nabil Ebraheim. Available from: http://www.youtube.com/watch?v=YfBw3Xcdg0s [last accessed 10/10/2020]
  10. ACM OTA Class of 2016. MMT Extensor pollicis longus & brevis. Available from: http://www.youtube.com/watch?v=ayMUlbSz7Cw [last accessed 10/10/2020]