528 THE MUSCLES AND FASCIA 



tendency of the superincumbent weight is to throw the leg inward : the Peroneus 

 longus overcomes this tendency by drawing on the outer side of the leg, and thus 

 maintains the perpendicular direction of the limb. 



Surgical Anatomy. The student should now consider the position of the tendons of the 

 various muscles of the leg, their relation with the ankle-joint and surrounding blood-vessels, and 

 especially their action upon the foot, as their rigidity and contraction give rise to one or other of 

 the kinds of deformity known as club-foot. The most simple and .common deformity, and one 

 that is rarely, if ever, congenital, is the talipes equinus, the heel being raised by rigidity and con- 

 traction of the Grastrocnemius muscle, and the patient walking upon the ball of the foot. In the 

 talipes varus the foot is forcibly adducted and the inner side of the sole raised, sometimes to a 

 right angle with the ground, by the action of the Tibialis anticus and posticus. In the talipes 

 valgus the outer edge of the foot is raised by the Peronei muscles, and the patient walks on the 

 inner ankle. In the talipes cakaneus the toes are raised by the extensor muscles, the heel is 

 depressed, and the patient walks upon it. Other varieties of deformity are met with, as the 

 talipes equino-varus, equino-valgus, and calcaneo-valgus, whose names sufficiently indicate their 

 nature. Of these, the talipes equino-varus is the most common congenital form : the heel is 

 raised by the tendo Achillis, the inner border of the foot drawn upward by the Tibialis anticus, 

 the anterior two-thirds twisted inward by the Tibialis posticus, and the arch increased by the 

 contraction of the plantar fascia, so that the patient walks on the middle of the outer border of 

 the foot. Each of these deformities may be successfully relieved (after other remedies fail) by 

 division of the opposing tendons and fascia : by this means the foot regains its proper position, 

 and the tendons heal by the organization of lymph thrown out between the divided ends. The 

 operation is easily performed by putting the contracted tendon upon the stretch, and dividing 

 it by means of a narrow, sharp-pointed knife inserted beneath it. 



Rupture of a few of the fibres of the Grastrocnemius or rupture of the Plantaris tendon not 

 uncommonly occurs, especially in men somewhat advanced in life, from some sudden exertion, 

 and frequently occurs during the game of lawn tennis, and is hence known as "lawn-tennis leg." 

 The accident is accompanied by a sudden pain, and produces a sensation as if the individual had 

 been struck a violent blow on the part. The tendp Achillis is also sometimes ruptured. It is 

 stated that John Hunter ruptured his tendo Achillis whilst dancing at the age of forty. 



THE FOOT. 



The fibrous bands which bind down the tendons in front of and behind the ankle in their 

 passage to the foot should now be examined ; they are termed the annular ligaments, and are 

 three in number anterior, internal, and external. 



The Anterior Annular Ligament consists of a superior or vertical portion, 

 which binds down the extensor tendons as they descend on the front of the tibia 

 and fibula, and an inferior or horizontal portion, which retains them in connection 

 with the tarsus, the two portions being connected by a thin intervening layer of 

 fascia. The vertical portion is attached externally to the lower end of the fibula, 

 internally to the tibia, and above is continuous with the fascia of the leg ; it con- 

 tains only one synovial sheath, for the tendon of the Tibialis anticus, the other 

 tendons and the anterior tibial vessels and nerve passing beneath it, but without 

 any distinct synovial sheath. The horizontal portion is attached externally to the 

 upper surface of the os calcis, in front of the depression for the interosseous 

 ligament ; it passes upward and inward as a double layer, one lamina passing in 

 front, and the other behind, the Peroneus tertius and Extensor longus digitorum. 

 At the inner border of the latter tendon these two layers join together, forming a 

 sort of loop or sheath in which the tendons are enclosed, surrounded by a synovial 

 membrane. From the inner extremity of this loop two bands are given off: one 

 passes upward and inward to be attached to the internal malleolus, passing over 

 the Extensor proprius hallucis and vessels and nerves, but enclosing the Tibialis 

 anticus and its synovial sheath by a splitting of its fibres. The other limb passes 

 downward and inward to be attached to the navicular and internal cuneiform 

 bones, and passes over both the tendon of the Extensor proprius hallucis and the 

 Tibialis anticus, and also the vessels and nerves. These two tendons are contained 

 in separate synovial sheaths situated beneath the ligament. It will thus be seen 

 that the horizontal portion of the ligament is like the letter Y> the foot of the letter 

 being attached to the os calcis, and the two diverging arms to the tibia and navic- 

 ular and internal cuneiform respectively. 



The Internal Annular Ligament is a strong fibrous band which extends from 

 the inner malleolus above to the internal margin of the os calcis below, converting 



