THE LEG 339 



ridges which limit that area anteriorly and posteriorly. It is 

 not equally dense throughout, but becomes thinner towards 

 the distal part of the leg until the region of the ankle is 

 reached, where thickened bands are formed in it ; beyond the 

 ankle in the region of the dorsum of the foot it becomes 

 exceedingly thin and fine. Its great strength in the proximal 

 part of the anterior crural region is due to the fact that there 

 it gives origin to fibres of the subjacent muscles. The bands 

 in the region of the ankle are formed to retain the tendons in 

 position when the muscles which move the joint are in action. 

 Four of the bands must be examined at this stage of the 

 dissection, viz., the ligamentum transversum cruris, the 

 ligamentum cruciatum cruris, and the superior and inferior 

 retinacula of the peroneal muscles. 1 



The ligamentum transversum cruris (O.T. upper part of 

 anterior annular ligament] is a strong, broad band which 

 stretches across the front of the leg, immediately proximal to 

 the ankle joint. By one extremity it is attached to the fibula, 

 and by the other to the tibia. The tig. cruciatum cruris (O.T. 

 lower part of anterior annular ligament} is placed over the ankle 

 joint. Laterally it presents the appearance of a narrow, well- 

 defined band, which is fixed firmly to the anterior part of the 

 calcaneus. As it passes medially it divides into two diverging 

 limbs. Of these the proximal is attached to the medial 

 malleolus, whilst the distal passes to the medial margin of the 

 foot, and becomes connected with the plantar aponeurosis. 

 The transverse and the cruciate ligaments of the leg are 

 merely portions of the deep fascia which are distinguishable 

 on account of their thickness (Figs. 153, 154). 



The superior peroneal retinaculum is a thickened por- 

 tion of the deep fascia which passes from the posterior and 

 distal part of the lateral malleolus to the upper and posterior 

 part of the lateral surface of the calcaneus (Fig. 158). 



The inferior peroneal retinaculum springs from the anterior 

 part of the upper surface of the calcaneus, where it is con- 

 tinuous with the lateral extremity of the cruciate ligament ; 

 its opposite extremity is attached, on the lateral border of the 

 foot, to the trochlear process of the calcaneus and to the 

 lateral surface of the calcaneus below that process. The 



1 In the old terminology the first two bands were respectively the upper 

 and lower parts of the anterior annular ligament of the ankle, and the last two 

 were included under the term external annular ligament. 

 I 22 a 



