POPLITEAL SPACE. 443 



between the Pectineus and Psoas muscles. On reaching the tendon of the Obtu- 

 rator externus, it divides into two branches ; one, ascending, is distributed to the 

 Adductor muscles, the Gracilis, and Obturator externus, anastomosing with the 

 obturator artery, the other descending, which passes beneath the Adductor brevis, 

 to supply it and the great Adductor ; the continuation of the vessel passing back- 

 wards, between the Quadratus femoris and upper border of the Adductor magnus, 

 anastomosing with the sciatic, external circumflex, and superior perforating arte- 

 ries. Opposite the hip-joint, this branch gives off an articular vessel, which 

 enters the joint beneath the transverse ligament ; and, after supplying the adipose 

 tissue, passes along the round ligament to the head of the bone. 



The Perforating Arteries (fig. 230), usually three in number, are so called from 

 their perforating the tendons of the Adductor brevis and Adductor magnus muscles 

 to reach the back of the thigh. The first is given off above the A dductor brevis, 

 the second in front of that muscle, and the third immediately below it. 



The first or superior perforating artery passes backwards between the Pectineus 

 and Adductor brevis (sometimes perforates the latter) ; it then pierces the Adduc- 

 tor magnus close to the linea aspera, and divides into branches which supply both 

 Adductors, the Biceps, and Gluteus maximus muscle; anastomosing with the 

 sciatic, internal circumflex, and middle perforating arteries. 



The second or middle perforating artery, larger than the first, pierces the tendons 

 of the Adductor brevis and Adductor magnus muscles, divides into ascending 

 and descending branches, which supply the Flexor muscles of the thigh, anasto- 

 mosing with the superior and inferior perforantes. The nutrient artery of the 

 femur is usually given off from this branch. 



The third or inferior perforating artery is given off below the Adductor brevis ; 

 it pierces the Adductor magnus, and divides into branches which supply the Flexor 

 muscles of the thigh, anastomosing with the perforating arteries, above, and with 

 the terminal branches of the profunda, below. 



Muscular Branches are given off from the superficial femoral throughout its 

 entire course. They vary from two to seven in number, and supply chiefly the 

 Sartorius and Vastus internus. 



The Anastomotica Magna arises from the femoral artery just before it passes 

 through the tendinous opening in the Adductor magnus muscle, and divides into 

 a superficial and deep branch. 



The superficial branch accompanies the long saphenous nerve, beneath the 

 Sartorius, and, piercing the fascia lata, is distributed to the integument. 



The deep branch descends in the substance of the Vastus internus, lying in front 

 of the tendon of the Adductor magnus, to the inner side of the knee, where it 

 anastomoses with the superior internal articular artery and recurrent branch of the 

 anterior tibial. A branch from this vessel crosses outwards above the articular 

 surface of the femur, forming an anastomotic arch with the superior external arti- 

 cular artery, and supplies branches to the knee-joint. 



THE POPLITEAL SPACE. 



Dissection. A vertical incision about eight inches in length should be made along the back 

 part of the knee-joint, connected above and below by a transverse incision passing from the inner 

 to the outer side of the limb. The flaps of integument included between these incisions should 

 be reflected in the direction shown in fig. 189. 



On removing the integument, the superficial fascia is exposed, and ramifying in 

 it along the middle line are found some filaments of the small sciatic nerve, and, 

 towards the inner part, some offsets from the internal cutaneous nerve. 



The superficial fascia having been removed, the fascia lata is brought into view. 

 In this region it is strong and dense, being strengthened by transverse fibres, and 

 firmly attached to the tendons on the inner and outer sides of the space. It is 

 perforated below by the external saphenous vein. This fascia having been reflected 

 back in the same direction as the integument, the small sciatic nerve and external 



