A retinaculum refers to any region on the body where tendon groups from different muscles pass under one connective tissue band. The inferior peroneal retinaculum is located in the ankle and foot regions. It is one of two parts of the peroneal retinaculum. The tendons of the inferior retinaculum cover the side of the ankle and run into the foot. (Tendons are connective tissue that usually connect muscle to bone.)

These tendons extend over the fibula, or calf bone, and the peroneus longus tendons attached to the peroneal muscles in the calf. They run into a ligament in the ankle joint known as the cruciate crural and continue from where the inferior extensor retinaculum ends.

The tendon’s point of attachment is the surface of the heel bone, or calcaneus. The inferior retinaculum is responsible for stabilizing the tendons that extend from the calf muscles as they run down the leg to reach both sides of the ankle.

Medical conditions that originate from an injury of the inferior peroneal retinaculum commonly affect athletes. The tendon can tear from forceful motions and the injury often requires at least six to eight weeks for the tendon to heal fully.