PLATE XXIII. 



THE FRONT OF THE LEG AND ANTERIOR TIBIAL ARTERY. 



Two dissections are represented in this plate, a superficial one showing the extensor 

 and peronei muscles in situ, and a second in which the extensors have been separated 

 from the tibialis anticus, and pulled out to expose the anterior tibial artery and nerve. 

 The peroneus longus has also been cut into, showing the course through it of the 

 anterior tibial and musculo-cutaneous nerves. 



The intermuscular septum between the peronei and ex- 

 tensor muscles can often be observed as a whitish line in the 

 deep fascia of the leg : this is a point to be avoided in ligaturing 

 the anterior tibial artery in its upper third : there is no such 

 u-hite line between the tibialis anticus and extensor longus digi- 

 torum, and the division of these two muscles is often hard to 

 determine owing to the fact that both arise from the fascia of 

 the leg, and that the upper part of the extensor tends to overlie 

 somewhat the tibialis antieus. The division between these two 

 muscles is about half an inch inside the septum between the 

 peronei and extensors. 



The skin supply of the front of the leg and dorsum of the 

 foot is shown in the accompanying diagram : (a) Long or 

 internal saphenous, (b) cutaneous twigs from the external 

 popliteal, (c) the two branches of the musculo-cutaneous usually 

 piercing the fascia separately, (e) external or short saphenous, 

 (/) anterior tibial. 



The nerve supply to the dorsum of the foot varies some- 

 what, but by far the most common arrangement is that shown in 

 the diagram. Sometimes, however, the external saphenous 

 supplies a branch to the inner side of the little and outer side 

 of the fourth, replacing a branch of the musculo cutaneous, and 

 thus supplying one and a half toes. Occasionally in the same 

 way, but more frequently, it may replace the two outer branches of the musculo- 

 cutaneous, and thus supply two and a half toes. 



The peroneus tertius is not met with except in man, and is a specialised slip of the 

 extensor longus digitorum, whose use is to raise the outer border of the foot in walking. 

 (Macalistur.) 



