The second slip of extensor digitorum brevis is the most medial of the four EDB slips, inserting into the second toe alongside the long extensor tendon. It augments second toe extension and contributes to the dorsal intrinsic mechanism. The four EDB slips decrease in size from medial to lateral.
| Origin | Dorsal surface of the calcaneus, lateral to the extensor digitorum brevis main belly |
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| Insertion | Dorsal surface of the proximal phalanx of the second toe and lateral aspect of the EDL tendon to the second toe |
| Nerve Supply | Deep peroneal nerve (L5, S1) |
| Blood Supply | Lateral tarsal artery, arcuate artery |
| Actions | Extends the second MTP joint; Assists dorsiflexion of the second toe |
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The EDB second slip is the largest and most clinically significant individual slip. Its hypertrophy in response to chronic toe extensor overload can create a dorsal foot mass that is mistaken for a ganglion or sinus tarsi mass. Avulsion of the EDB from the calcaneus occurs in lateral ankle sprains and must be distinguished from an anterior process calcaneal fracture on X-ray. The second slip belly is the landmark for the sinus tarsi approach.
Palpated on the dorsum of the foot lateral to the extensor hallucis longus tendon, becoming prominent with resisted second toe extension.
Traction avulsion of the extensor digitorum brevis origin in lateral ankle sprain, producing anterolateral foot pain mimicking anterior calcaneal process fracture, confirmed by CT showing soft-tissue injury without bony avulsion.
