THE LEG 261 



tion of the sural nerve, the superficial peroneal nerve furnishes 

 twigs to the two margins of each of the toes (Fig. 98, p. 269). 



Very frequently the distribution of the superficial peroneal 

 nerve is more restricted, and in these cases the lateral dorsal 

 cutaneous nerve will, in all probability, be found to supply 

 the lateral two and a half toes. 



The nervus peronceus profundus (O.T. anterior tibial nerve), 

 or rather its medial terminal branch, pierces the deep fascia 

 on the dorsum of the foot in the interval between the first 

 and second metatarsal bones. It receives a communicating 

 branch from the medial dorsal cutaneous nerve, and ends 

 by dividing into two twigs, which go to supply the adjacent 

 margins of the great toe and the second toe. 



Deep Fascia. The fatty superficial fascia should be re- 

 moved in order that the deep fascia may be displayed. This 

 aponeurosis does not form a complete investment for the leg. 

 It is absent over the medial area of the tibia, and is attached 

 to the anterior and medial borders of that bone. It is also 

 absent over the triangular subcutaneous surface on the distal 

 part of the fibula, being attached to the ridges which limit 

 that area anteriorly and posteriorly. It is not equally dense 

 throughout. In the proximal part of the anterior crural 

 region it is thick and strong, but it thins as it is traced 

 distally, and on the dorsum of the foot it becomes exceedingly 

 fine. Its great strength in the proximal part of the anterior 

 crural region is due to the fact that there it gives origin to 

 subjacent muscles. In the neighbourhood of the ankle-joint 

 it forms the thickened bands which retain the tendons in 

 position during the action of the muscles. Four of these 

 may be examined at this stage, viz. the lig. transversum 

 cruris, the lig. cruciatum cruris, and the superior and in- 

 ferior 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 Kg. cruciatum cruris (O.T. 

 lower part anterior annular ligament) is placed over the ankle- 

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



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. 



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