Extensor digitorum brevis muscle

Gray441

Extensor digitorum brevis muscle is a muscle located in the foot, specifically on the dorsal aspect (top side) of the foot. It is an important muscle for the extension of the four lesser toes of the foot. The muscle originates from the calcaneus bone and extends into four tendons, each of which inserts into the proximal phalanx of toes two through five. The primary function of the extensor digitorum brevis is to aid in the extension of the toes, which is crucial for the push-off phase of the walking cycle.

Anatomy

The extensor digitorum brevis muscle is situated on the top of the foot, just beneath the skin and fascia. It originates from the anterior part of the upper surface of the calcaneus, the heel bone. From its origin, the muscle divides into four separate tendons, each of which inserts into the base of the proximal phalanx of the second to fifth toes. These tendons are also connected to the tendons of the extensor digitorum longus muscle, which is a muscle in the leg that also assists in extending the toes.

Innervation

The extensor digitorum brevis muscle is innervated by the deep fibular (peroneal) nerve, which is a branch of the sciatic nerve. This nerve provides the muscle with the ability to contract and thus extend the toes.

Function

The primary function of the extensor digitorum brevis muscle is to extend the second to fifth toes at the metatarsophalangeal joints (the joints where the toes connect to the foot). This action is particularly important during the push-off phase of walking, running, or any activity that requires pushing the body forward from the toes. By extending the toes, the muscle helps to stabilize the foot and provides leverage that aids in propulsion.

Clinical Significance

Injury or dysfunction of the extensor digitorum brevis can lead to difficulties in toe extension, affecting gait and balance. Conditions such as extensor tendonitis can cause pain and swelling in the area of the muscle, particularly during activities that involve toe extension. Additionally, variations in the anatomy of the extensor digitorum brevis muscle can sometimes be observed, which may have implications for surgical procedures involving the foot.

See Also

• Extensor digitorum longus muscle
• Foot anatomy
• Muscles of the lower limb