3 io PRACTICAL ANATOMY. 



ANTERIOR REGION OF LEG. 



Remove carefully the deep fascia. (Fig. 210.) You have now, by the re- 

 moval of the skin and superficial fascia, exposed the deep fascia covering all the 

 muscles on the anterior and outer regions of the leg (Fig. 213): 



1. The cutaneous branch of the musculo-cutaneous nerve. 



2. The tibialis anticus and the tuberosity of scaphoid bone. 



3. The extensor proprius hallucis muscle. 



4. The extensor longus digitorum muscle. 



5. The peroneus tertius muscle. 



6. The extensor brevis digitorum muscle. 



Now dissect down between the tibialis anticus and the extensor proprius 

 hallucis by cutting through the deep fascia with scissors and find the anterior 

 tibial nerve and vessels. (Fig.-2i4.) 



Anterior Tibial Artery. It is one of the two terminal branches of the pop- 

 liteal artery. It gains the front of the leg by passing between the two heads of 

 the tibialis posticus and interosseous membrane. It lies in a deep groove, bounded 

 internally by the tibialis anticus ; externally, by the extensor longus digitorum 

 and extensor proprius hallucis. It terminates on the dorsum of the foot, continu- 

 ing its course under the name of dorsalis pedis. Its branches are : (i) The ante- 

 rior tibial recurrent, which anastomoses with the articular branches of the popliteal 

 and anastomotica magna ; (2) posterior tibial recurrent, when present, is given off 

 before the anterior tibial passes through the interosseous membrane ; (3) mus- 

 cular branches, which supply the muscles on the anterior region of the leg (Fig. 

 214) ; (4) malleolar branches, which supply the ankle-joint. On the back of the 

 foot you cut through the deep fascia between the extensor proprius hallucis and 

 extensor longus digitorum muscles, to find the dorsalis pedis artery. 



Dorsalis Pedis Artery. This is a continuation of the anterior tibial. It lies 

 between the extensor proprius hallucis and extensor longus digitorum, on the 

 dorsum of the foot. (Fig. 214.) It gives off: (i) A communicating branch to 

 the external plantar, by which the plantar arch is completed ; (2) a tarsal 

 artery to the extensor brevis digitorum and the tarsus ; (3) the dorsalis hallucis 

 to the great toe ; (4) interosseous arteries to the interosseous spaces and their 

 contents. Trace the arteries out carefully with the forceps. Remember they 

 are beneath the dorsal fascia. 



Anterior Tibial Nerve. It is a branch of the external popliteal nerve, being 

 given off with the musculo-cutaneous nerve. It gives off articular branches, ac- 

 cording to Hilton's law, to the (i) ankle-joint, (2) the tarsal, and (3) the metatarso- 

 phalangeal joints. It gives muscular branches to the extensor brevis digitorum 

 and to all the muscles on the anterior regions of the tibia and fibula. 



Muscles on Anterior Surface of Fibula. These are : ( i ) Extensor proprius 

 hallucis ; (2) extensor longus digitorum ; (3) peroneous tertius, the fifth tendon 

 of the extensor longus digitorum. 



Insertion of Extensor Brevis Digitorum. This muscle has four tendons. 

 The first is inserted independently into the base of the first phalanx of the great 

 toe; the remaining three are inserted, conjointly with the tendons of the 

 extensor longus digitorum, into the bases of the second and third phalanges. 



Give nerve-supply of the five muscles now exposed on the anterior tibio-fibular 

 region. 



The anterior tibial, a branch of the external popliteal 



Intermuscular Septum. Examine the septum that separates the muscles on 

 the anterior surface of the fibula from the peronei on the external surface. 



How to Dissect these Muscles. Tibialis Anticus. Cut through the 



