Nerve Deep fibular nerve | ||
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Insertion Proximal dorsal region of middle phalanges 2, 3 and 4 Actions Extends digits 2 through 4 Antagonist Flexor digitorum longus, Flexor digitorum brevis | ||
The extensor digitorum brevis muscle (sometimes EDB) is a muscle on the upper surface of the foot that helps extend digits 2 through 4.
Contents
Structure
Origin: forepart of upper and lateral surface of calcaneus, in front of groove for peroneus brevis, from interosseous talocalcaneal ligament, stem of inferior extensor retinaculum.
Course
Course: fibres pass obliquely forwards and medially cross dorsum of foot and end in four tendons. The medial part of muscle ends in tendon which crosses the dorsalis pedis artery, inserts into dorsal surface base of PPX of great toe and is termed extensor hallucis brevis. The other three tendons insert into lateral sides of tendon of extensor digitorum longus which insert into the 2nd, 3rd and 4th toes.
Innervation
Nerve supply: lateral terminal branch of Deep Peroneal Nerve (deep fibular nerve) (proximal sciatic branches L4-L5, but most clinically relevant L5 with L4/L5 spinal disc herniation causing L5 lesion). Same innervation of Extensor Hallucis Brevis
Action
Action: extends MTP of 1st to 4th digits and assists in extending the IP joints of 2nd, 3rd, and 4th digits.
Note: without EDL there is no extension of 5th digit.