432 The Pop! it c.i I Space 



the vein gradually mounts on to the artery ; and so, behind the plane 

 of the joint, the nerve is nearest the skin, the artery is upon the pos- 

 terior ligament, and the vein is lx-t ween the two. 



Having emerged from the intercondylar pass, the three structures 

 spread out again, so that, as they rest upon the popliteus, the vein 

 has dismounted from the artery on to its inner side, whilst the nerve 

 is still more internal. At the lower border of the popliteus the artery 

 divides into the anterior and posterior tibials, and the nerve changes 

 its name to posterior tibial. 



Xiigation of the popliteal artery is rarely performed, first be- 

 cause of the extreme depth of the vessel in the space, and secondly 

 because of an intimate fibrous adhesion which connects it with the 

 vein. It is, therefore, resorted to only in the case of a wound of the 

 artery, in every other case ligation of the superficial femoral being the 

 preferable operation. 



The popliteal artery can, however, be reached without much diffi- 

 culty from the inner side, by a three-inch incision along the gap which 

 can be made out by the fingers just in front of the semi-membranosus 

 and gracilis, and behind the vastus internus and the tendon of the 

 adductor magnus. 



The internal saphenous vein must be avoided, and, the fascia lata 

 having been divided on a director, and the sartorius having been 

 recognised and drawn backwards with the tendon of the gracilis, the 

 rigid tendon of the adductor magnus with the fleshy fibres of the 

 vastus internus are seen. The long saphenous nerve may also be 

 seen sloping backwards under the sartorius. The artery is looked 

 for by working towards the back of the femur with the forceps and 

 director. (The sartorius being to the inner side of the artery, the vein 

 is, of course, to the outer side.) 



Branches of the popliteal artery. Superior muscular, to the 

 hamstrings and the adductor magnus, which anastomose with the 

 ending of the deep femoral, with other perforating branches, and with 

 the comes nervi ischiatici. Inferior muscular (sural) to the muscles 

 of the calf. Five articular branches, each of which runs under or 

 through some important fibrous structure. The superior inferno/ 

 articular winds under the tendon of the adductor magnus, to join the 

 inastomotica magna, the superior external, and also the inferior 

 internal articular. The last-named branch passes under the internal 

 lateral ligament, in the groove below the head of the tibia, and anasto- 

 moses with the superior external articular, which passes under the 

 tendon of the biceps, and joins the descending branches of th< ex- 

 ternal circumflex, the anastomotica magna, and the superior internal 

 irticular. 



The inferior external articular passes above the head of the fibu'a, 

 under the tendon of the biceps and the external lateral ligament. It 

 anastomoses with the inferior internal, and the superior external 



