524 ARTERIES. 



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



POPLITEAL ARTERY. 



The Popliteal Artery commences at the termination of the femoral, at the 

 opening in the Adductor Magnus, and, passing obliquely downwards and out- 

 wards behind the knee-joint to the lower border of the Popliteus muscle, divides 

 into the anterior and posterior tibial arteries. Through the whole of this extent 

 the artery lies in the popliteal space. 



THE POPLITEAL SPACE. (Fig. 299.) 



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 from the inner to the 

 outer side of the limb. The flaps of integument included between these incisions should be re- 

 flected in the direction shown in Fig. 256, p. 412. 



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 saphenous vein are seen immediately beneath it, in 

 the middle line. If the loose adipose tissue is now removed, the boundaries and 

 contents of the space may be examined. 



Boundaries. The popliteal space, or the ham, occupies the lower third of the 

 thigh and the upper fifth of the leg ; extending from the aperture in the Ad- 

 ductor Magnus, to the lower border of the Popliteus muscle. It is a lozenge- 

 shaped space, being widest at the back part of the knee-joint, and deepest above 

 the articular end of the femur. It is bounded, externally, above the joint, by 

 the Biceps, and below the joint by the Plantaris and external head of the Gas- 

 trocnemius. Internally, above the joint, by the Semimernbranosus, Semiten- 

 dinosus, Gracilis, and Sartorius ; below the joint, by the inner head of the 

 Gastrocnemius. 



Above, it is limited by the apposition of the inner and outer hamstring mus- 

 cles ; below by the junction of the two heads of the Gastrocnemius. The floor 

 is formed by the lower part of the posterior surface of the shaft of the femur, 

 the posterior ligament of the knee-joint, the upper end of the tibia, and the 

 fascia covering the Popliteus muscle, and the space is covered in by the fascia 

 lata. 



Contents. It contains the popliteal vessels and their branches, together wit 

 the termination of the external saphenous vein, the internal and external pop- 

 liteal nerves and their branches, the small sciatic nerve, the articular branch 

 from the obturator nerve, a few small lymphatic glands, and a considerabl 

 quantity of loose adipose tissue. 



Position of contained parts. The internal popliteal nerve descends in the 

 middle line of the space, lying superficial and a little external to the vein and 

 artery. The external popliteal nerve descends on the outer side of the space, 

 lying close to the tendon of the Biceps muscle. More deeply at the bottom of 

 the space are the popliteal vessels, the vein lying superficial and a little ex- 

 ternal to the artery, to which it is closely united by dense areolar tissue ; some- 

 times the vein is placed on the inner instead of the outer side of the artery; 



