444 ARTERIES. 



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 Adductor 

 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 arti- 

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

 and below the articulation, by the Plantaris and external head of the Gastroc- 

 nemius ; internally, above the joint, by the Semi-membranosus, Semi-ten- 

 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 muscles: 

 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 with the 

 termination of the external saphenous vein, the internal and external popliteal 

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

 obturator nerve, a few small lymphatic glands, and a considerable 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 external to the artery, 

 to which it is closely united by dense areolar tissue ; sometimes the vein is placed 

 on the inner instead of the outer side of the artery ; or the vein may be double, 

 the artery then lying between them, the two veins being usually connected by short 

 transverse branches. More deeply, and close to the surface of the bone, is the 

 popliteal artery, and passing off from it at right angles are its articular branches. 

 The articular branch from the obturator nerve descends upon the popliteal artery 

 to supply the knee ; and occasionally there is found deep in the space an articular 

 filament from the great sciatic nerve. The popliteal lymphatic glands, four or 

 five in number, are found surrounding the artery ; one usually lies superficial to 

 the vessel, another is situated between it and the bone, and the rest are placed on 

 either side of it. In health, these glands are small ; but when enlarged and indu- 

 rated from inflammation, the pulsation communicated to them from the popliteal 

 artery makes them resemble so closely an aneurismal tumor, that it requires a 

 very careful examination to discriminate between them. 



POPLITEAL ARTEEY. 



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

 opening in the Adductor magnus, and, passing obliquely downwards and outwards 

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

 the anterior and posterior tibial arteries. Through this extent the artery lies in 

 the popliteal space. 



In its course downwards from the aperture in the Adductor rnagnus to the lower 

 border of the Popliteus muscle, the Popliteal artery (fig. 232) rests first on the 

 inner, and then on the posterior surface of the femur ; in the middle of its course, 

 on the posterior ligament of the knee-joint ; and below, on the fascia covering 

 the Popliteus muscle. Superficially, it is covered, above, by the Semi-membra- 

 nosus ; in the middle of its course, by a quantity of fat, which separates it from the 

 deep fascia and integument ; and below, it is overlapped by the Gastrocnemius, 

 Plantaris and Soleus muscles, the popliteal vein, and the internal popliteal nerve. 



