POPLITEAL SPACE. 285 



which is continuous with the fascia covering the popli- 

 teus muscle, and a posterior, which expands upon the 

 posterior surface of the knee-joint and is attached to the 

 outer condyle of the femur, constituting what is called the 

 ligament um posticurii Winslowii of the knee-joint. The 

 tendons of the semi-membranosus and semi-tendinosus form 

 the inner ham-string, and with that of the gracilis, from a 

 fancied resemblance, derived from their divergence, have 

 received the name of the pes anserinus. 



The SCIATIC NERVE, surrounded b}' a consider able amount 

 of fat and areolar tissue, will have been traced in the fore- 

 going dissection (p. 231). At the upper part of the thigh 

 it is comparatively superficial, there being no muscle 

 between it and the integument ; it then passes underneath 

 the long head of the biceps, and down upon the outer side 

 of the median line of the thigh to the popliteal space, giving 

 >ff, in its course, branches to the muscles of the posterior 

 amoral region, between which it lies, and a single articular 

 >ranch to the knee-joint. Toward the lower part of the 

 tigh, it divides into the popliteal and peroneal branches ; 

 )metimes this division takes place higher up, even before 

 emerging from the pelvis; in which case, as has been seen, 

 me of the branches perforates the pyriformis muscle. 



POPLITEAL SPACE. 



The POPLITEAL SPACE is the diamond-shaped interval 

 itween the biceps and semi-tendinosus and semi-membran- 

 >sus muscles above, and the separated heads of the gas- 

 trocnemius muscle below; its base, or floor, being the flat 

 surface of the femur above the condyles ; the fascia lata 

 and integument cover it superficially, and it is traversed by 

 the popliteal artery and vein, and the popliteal nerve with 

 its branches. The relative position of these is as follows : 

 The popliteal nerve is the most superficial, and its situation 

 corresponds to the long diameter of the popliteal space ; 

 immediately beneath the nerve is the popliteal vein, and 

 directly under the vein, the popliteal artery, the nerve, vein, 

 and artery lying superimposed one upon another. Be- 

 tween the nerve and the vein there is usually an interval 

 filled with fat. 



The branches of the sciatic nerve which are superficial 

 are to be examined first. 



Theperonea/ division of the sciatic nerve is smaller in size than the 

 popliteal ; it accompanies the tendon of the biceps mnscle to the head 



