Henry Gray (18251861). Anatomy of the Human Body. 1918.
Actions.The Peronæi longus and brevis extend the foot upon the leg, in conjunction with the Tibialis posterior, antagonizing the Tibialis anterior and Peronæus tertius, which are flexors of the foot. The Peronæus longus also everts the sole of the foot, and from the oblique direction of the tendon across the sole of the foot is an important agent in the maintenance of the transverse arch. Taking their fixed points below, the Peronæi serve to steady the leg upon the foot. This is especially the case in standing upon one leg, when the tendency of the superincumbent weight is to throw the leg medialward; the Peronæus longus overcomes this tendency by drawing on the lateral side of the leg.
8d. The Fasciæ Around the Ankle
Fibrous bands, or thickened portions of the fascia, bind down the tendons in front of and behind the ankle in their passage to the foot. They comprise three ligaments, viz., the transverse crural, the cruciate crural and the laciniate; and the superior and inferior peroneal retinacula.
FIG. 441 The mucous sheaths of the tendons around the ankle. Lateral aspect. (See enlarged image)
Transverse Crural Ligament (ligamentum transversum cruris; upper part of anterior annular ligament) (Fig. 441).The transverse crural ligament binds down the tendons of Extensor digitorum longus, Extensor hallucis longus, Peronæus tertius, and Tibialis anterior as they descend on the front of the tibia and fibula; under it are found also the anterior tibial vessels and deep peroneal nerve. It is attached laterally to the lower end of the fibula, and medially to the tibia; above it is continuous with the fascia of the leg.
Cruciate Crural Ligament (ligamentum cruciatum cruris; lower part of anterior annular ligament) (Figs. 441,442).The cruciate crural ligament is a Y-shaped band placed in front of the ankle-joint, the stem of the Y being attached laterally to the upper surface of the calcaneus, in front of the depression for the interosseous talocalcanean ligament; it is directed medialward as a double layer, one lamina passing in front of, and the other behind, the tendons of the Peronæus tertius and Extensor digitorum longus. At the medial border of the latter tendon these two layers join together, forming a compartment in which the tendons are enclosed. From the medial extremity of this sheath the two limbs of the Y diverge: one is directed upward and medialward, to be attached to the tibial malleolus, passing over the Extensor hallucis longus and the vessels and nerves, but enclosing