Flexor retinaculum of the foot
Each wrist and ankle of the human body contains a structure called a flexor retinaculum. A flexor retinaculum consists of a fibrous band of fascia, which is a sheet of dense connective tissue that covers or binds other body structures. The flexor retinaculum of the foot, also known as the laciniate ligament, covers the tendons of the flexor muscles of the ankle. The specific tendons covered are the tibialis posterior, flexor digitorum longus, and flexor hallucis longus. The function of the laciniate ligament is to prevent subluxation, or partial dislocation, of these tendons. The posterior tibial artery and vein, and the tibial nerve, are also covered by the flexor retinaculum of the foot. Each of these structures comes from the posterior compartment of the leg, through the ankle, and into the sole of the foot. They pass through the flexor retinaculum immediately posterior to the medial melleolus, which is the network of nerve tissue and muscle that surrounds the ankle joint.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Flexor retinaculum of the foot