THE POPLITEAL ARTERY. 581 



accompanies the long saphenous nerve to the inner side of the thigh. It passes 

 between the Sartorius and Gracilis muscles, and, piercing the fascia lata, is distrib- 

 uted to the integument of the upper and inner part of the leg, anastomosing with 

 the inferior internal articular. 



The deep branch descends in the substance of the Yastus 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 anterior recurrent 

 branch of the anterior tibial. A branch from this vessel crosses outward 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 downward and outward 

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

 the anterior and posterior tibial arteries. A portion of the artery lies in the 

 popliteal space ; but above and below, to a considerable extent, it is covered by 

 the muscles which form the boundaries of the space, and is therefore beyond the 

 confines of the hollow. 



THE POPLITEAL SPACE (Fig. 320). 



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 reflected in the direction shown in Fig. 255, page 427. 



Boundaries. The popliteal space, or the ham, is a lozenge-shaped space, 

 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 Gastrocnemius. Internally, 

 above the joint, by the Semimembranosus, Semitendinosus, 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 some of their branches, the lower extremity of the small sciatic nerve, 

 the articular branch from the obturator nerve, a feAV 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 crossing the artery from without 

 inward. The external popliteal nerve descends on the outer side of the upper 

 part 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 to 

 the artery, to which it is closely united by dense areolar tissue ; it is a thick- 

 walled vessel, and lies at first to the outer side of the artery, and then crosses 

 it to gain the inner side below ; sometimes the vein is double, the artery lying 

 between the two venge comites, which are usually connected by short transverse 

 branches. More deeply, and, at its upper part, 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 



