Inferior extensor retinaculum
The inferior extensor retinaculum is located in the foot and is a band located in front of the ankle joint that is Y-shaped. The stem of the Y-shaped band is attached in a lateral direction to the calcaneus' upper surface. The calcaneus is the medical term for the heel bone. This band is also located in front of the interosseous talocalcanean ligament, which is what forms the union bond between all of the bones. It is considered a double layer due to one lamina passing behind and the other passing in front of the tendons of the Extensor digitorum longus and the Peroneus tertius. The Extensor digitorum longus muscle is located on the lateral portion of the front part of the leg. The Peroneus tertius muscle is also located in the lower limb. The two layers of the inferior extensor retinaculum come together to form a compartment that encloses the tendons. From the middle of the sheath, the Y's two limbs split -- one going upwards and the other towards the middle -- so that they both pass over the Extensor hallucis longus and attach to the tibial malleolus.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Inferior extensor retinaculum