The extensor hallucis brevis is technically the medial portion of the extensor digitorum brevis, providing a short intrinsic extensor to the great toe that supplements the EHL. Its small muscle belly on the dorsolateral foot contributes to the EDB muscle mass palpable there. EHB atrophy is a sensitive early indicator of L5 nerve root or deep peroneal nerve compromise because it is an exclusively intrinsic muscle dependent on the nerve for its entire motor supply.
| Origin | Anterior calcaneus, considered the medial portion of the extensor digitorum brevis |
|---|---|
| Insertion | Dorsal surface of the base of the proximal phalanx of the great toe |
| Nerve Supply | Deep peroneal nerve (L5, S1) |
| Blood Supply | Dorsalis pedis artery |
| Actions |
|
|---|
It supplements the EHL in extending the great toe MTP joint, important during the swing phase of gait for toe clearance and during balance activities requiring active toe extension.
EHB atrophy is assessed clinically by comparing the dorsolateral foot bulk between sides and is an early, sensitive sign of L5 radiculopathy because intrinsic foot muscles denervate before the larger tibialis anterior. The EHB contributes to the Babinski response alongside the EHL when the plantar surface is stroked.
The EHB forms the medial portion of the rounded dorsolateral foot muscle mass and is distinguished from the main EDB by its course toward the great toe, becoming firm during isolated great toe extension.
Early L5 or deep peroneal nerve compromise producing EHB atrophy detectable as asymmetric dorsolateral foot wasting before tibialis anterior weakness becomes clinically apparent.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
