166 LABORATORY MANUAL OF HUMAN ANATOMY 



incision already made in the dissection of the fossa poplitea 

 down to the heel; at the distal extremity of this make a trans- 

 verse incision extending for five centimetres along the margo 

 pedis lateralis and margo pedis medialis. Eeflect the flaps. 



Note the general characteristics of this fascia as regards the 

 amount of fat contained, the general direction of its fibres, and 

 the strength of the same. In it, dissect out carefully the fol- 

 lowing : 



Veins. (Vide Spalteholz, Fig. 509.) 



(a) Small saphenous vein (vena saphena parva) (0. T. external saphe- 



nous vein). What is its relation to the malleolus lateralis? Note 

 that it is the continuation of the lateral marginal vein of the 

 foot (vena marginalis lateralis) into the leg. In the upper half 

 of the leg this vein is ensheathed by a duplicature of the fascia 

 cruris. Dissect out the two branches into which it bifurcates 

 above and trace these out into the vena poplitea and the vena 

 femoris profunda. What is the relation of the vena femoro- 

 poplitea to the latter? Trace one of the perforating veins 

 through the fascia cruris. Incise the vein longitudinally and 

 determine whether it has valves or not. 



(b) Large saphenous vein (V. saphena magna) (0. T. internal saphe- 



nous). Determine its relation to the malleolus medialis. It is 

 the continuation of the medial marginal vein (vena marginalis 

 medialis) of the foot into the leg. Do you find a collateral vein 

 accompanying it? When present, it will be found just posterior 

 to the large vein. Incise the vein longitudinally and determine 

 the characteristics of its valves. 



Nerves. (Fig. 69.) 



(a) Nerve of the calf (N. suralis) (0. T. short saphenous nerve). This 



nerve is formed by the union of the following: 



(aa) Medial cutaneous nerve of the calf (N. cutaneus surae 



medialis). In the greater part of its course this nerve 

 will be found beneath the fascia cruris. At the middle 

 of the leg it pierces this fascia to become subcutaneous. 



(ab) Anastomotic peroneal branch of the N. cutaneus surae 



lateralis (ramus anastomoticus peronaeus}. 



(b) Lateral cutaneous nerve of calf (N. cutaneus surae lateralis) (0. 



T. nervus communicans fibularis). 



(c) Posterior cutaneous nerve of thigh (N. cutaneus femoris posterior) 



(0. T. small sciatic). This nerve will be found beneath the fascia 

 cruris. It sends twigs through the fascia to end in the skin. 



(d) Medial cutaneous branches (rami cutanei cruris mediales) to the 



leg from the N. saphenus. Determine the area of skin supplied 

 by each nerve. 



Eemove the superficial fascia of the leg, and study the deep 

 fascia. 



