Lower limb

Extensor digitorum brevis

Musculus extensor digitorum brevis

Origin

Dorsal surface of the calcaneus (sinus tarsi region), inferior extensor retinaculum

Insertion

Extensor expansion of the second, third and fourth toes, attaching onto the middle phalanx

Function

Extension of the second to fourth toes at the MTP and PIP joints, supplementing extensor digitorum longus

Innervation

Deep fibular (peroneal) nerve, L5-S1

Movement & chain

Supplements the action of extensor digitorum longus in extending toes 2-4, and is particularly active during the swing phase of gait to ensure adequate toe clearance.

Palpation

Palpable as a small muscle belly on the dorsum of the foot, just in front of the lateral malleolus, which tenses during toe extension.

Clinical

The muscle belly can produce a palpable swelling on the dorsum of the foot that is sometimes mistaken for a ganglion or other soft-tissue tumor.

Segmental innervation

L5–S1 (deep fibular nerve)

In clinical practice

Skin and pressure point inspection; maintain comfortable positioning and proper body mechanics during patient handling and daily care.

Region in the model

Lower limb