THE LEG 353 



phalangeal joints of the great toe, and frequently, also, a 

 fine muscular twig to the dorsal surface of the first dorsal 

 interosseous muscle. 



The lateral terminal branch of the deep peroneal nerve 

 turns abruptly laterally, under cover of the extensor digitorum 

 brevis, and ends on the dorsum of the tarsus in a gangliform 

 enlargement. Branches proceed from the enlargement to 

 supply the extensor digitorum brevis and the numerous 

 articulations in the neighbourhood. One fine filament can, 

 in some cases, be traced to the second dorsal interosseous 

 muscle. The terminal swelling resembles closely the corre- 

 sponding enlargement in which the dorsal interosseous nerve 

 of the superior extremity ends (see p. 185). 



Ligamentum Transversum Cruris et Ligamentum Cruciatum 

 (O.T. Anterior Annular Ligament). The dissector should 

 now re-examine the transverse and cruciate ligaments, and 

 the arrangement of the structures which pass deep to them. 

 The transverse ligament is attached to the fibula by its lateral 

 end, and to the tibia by its medial extremity. If the 

 fibular attachment is divided, and the ligament is thrown 

 medially, it will be seen to contain a distinct compartment for 

 the tibialis anterior and its mucous sheath. 



The cruciate ligament is the more important of the two. 

 Its attachments have already been noted (p. 339). Examine 

 the manner in which it holds the tendons in position. It 

 consists of two layers, and these, by separating at certain 

 points and becoming reunited at others, form three distinct 

 compartments. The tendon of the tibialis anterior passes 

 through the medial compartment, the tendon of the ex- 

 tensor hallucis longus traverses the intermediate one, and the 

 tendons of the extensor digitorum longus and peronaeus 

 tertius are transmitted through the lateral compartment. 

 As the tendons pass through the compartments of the 

 ligaments, and for some distance proximal to the transverse 

 ligament and distal to the cruciate ligament, they are 

 surrounded by mucous sheaths (see p. 341). Lastly, note 

 the position of the anterior tibial vessels and the deep 

 peroneal nerve as they pass under cover of the ligaments. 

 They lie between the extensor hallucis longus and the 

 extensor digitorum longus (Fig. 156, p. 349). 



VOL. i 23 



