extrinsic foot muscles origin insertions

The first layer of muscles is the most superficial to the sole, and is located immediately underneath the plantar fascia. The muscles of the plantar aspect are described in four layers (superficial to deep). All the muscles are innervated either by the medial plantar nerve or the lateral plantar nerve, which are both branches of the tibial nerve.

They act collectively to stabilise the arches of the foot, and individually to control movement of the digits. There are 10 intrinsic muscles located in the sole of the foot. (Note – some texts consider the extensor hallucis brevis to be merely the medial part of the extensor digitorum brevis) Actions: Aids the extensor hallucis longus in extending the great toe at the metatarsophalangeal joint.It attaches to the base of the proximal phalanx of the great toe. Attachments: Originates from the calcaneus, the interosseous talocalcaneal ligament and the inferior extensor retinaculum.The extensor hallucis brevis muscle is medial to extensor digitorum longus and lateral to extensor hallucis longus. Actions: Aids the extensor digitorum longus in extending the medial four toes at the metatarsophalangeal and interphalangeal joints.It attaches to proximal phalanx of the great toe and the long extensor tendons of toes 2-4. Attachments: Originates from the calcaneus, the interosseous talocalcaneal ligament and the inferior extensor retinaculum.The extensor digitorum brevis muscle lies deep to the tendon of the extensor digitorum longus. Both muscles are innervated by the deep fibular nerve. They are mainly responsible for assisting some of the extrinsic muscles in their actions. Whilst many of the extrinsic muscles attach to the dorsum of the foot, there are only two intrinsic muscles located in this compartment – the extensor digitorum brevis, and the extensor hallucis brevis.

Extrinsic foot muscles origin insertions