626 DISSECTION OF THE LEG. 



SECTION VI. 



THE FRONT OF THE LEG. 



Position. The limb is to be raised to a convenient height by blocks 

 beneath the knee, and the foot is to be extended in order that the muscles 

 on the front of the leg may be put on the stretch. 



Dissection. To enable the dissector to raise the skin from the leg and 

 foot, one incision should be made along the middle line from the knee to 

 the toes, and this should be intersected by cross cuts at the ankle and the 

 root of the toes. 



After the flaps of skin are reflected, the cutaneous vessels and nerves are 

 to be looked for. At the upper and inner part of the leg are some fila- 

 ments from the great saphenous nerve ; and at the outer side others, still 

 smaller, from the external popliteal nerve. Perforating the fascia in the 

 lower third, on the anterior aspect, is the musculo-cutaneous nerve, whose 

 branches should be pursued to the toes. 



On the dorsum of the foot is a venous arch, which ends laterally in the 

 saphenous veins. On the outer side is the external saphenous nerve ; and 

 about the middle of the instep the internal saphenous nerve ceases. In the 

 interval between the great toe and the next is the cutaneous part of the 

 anterior tibial nerve. 



The digital nerves should be traced to the ends of the toes by removing 

 the integuments : and after the several vessels and nerves are dissected, 

 the fat is to be taken away, in order that the fascia may be seen. 



The venous arch on the dorsum of the foot has its convexity turned 

 forwards, and receives digital branches from the toes ; at its concavity it 

 is joined by small veins from the instep. Internally and externally it 

 unites with the saphenous veins. 



The internal saphenous vein begins at the inner side of the great toe, 

 and in the arch. It ascends along the inner side of the foot, and in front 

 of the inner ankle to the inside of the leg (p. 606). Branches enter it 

 from the inner side and sole of the foot. 



The external saphenous vein begins on the outside of the little toe and 

 foot, as well as in the venous arch ; and it is continued below the outer 

 ankle to the back of the leg (p. 606). 



CUTANEOUS NERVES (fig. 214). The superficial nerves on the front 

 of the leg and foot are derived mainly from branches of the popliteal 

 trunks, viz., from the musculo-cutaneous and anterior tibial nerves of the 

 external popliteal, and from the external saphenous nerve of the internal 

 popliteal. Some inconsiderable offsets ramify on the sides of the leg from 

 the internal saphenous and external popliteal. 



The musculo-cutaneous nerve ( 2 ) ends on the dorsum of the foot and 

 toes. Perforating the fascia in the lower third of the leg with a cutane- 

 ous artery, it divides into two principal branches (inner and outer), which 

 give dorsal digital nerves to the sides of all the toes, except the outer part 

 of the little toe and the contiguous sides of the great toe and the next. 

 The branches may be traced in the integument as far as the end of the 

 last phalanx. 



The inner branch ( 3 ) communicates with the internal saphenous nerve, 



