1188 



SURGICAL AND TOPOGRAPHICAL AXATOMY. 



of these structures, which usually prevents popliteal aneurism and abscess from 

 making their way into the joint. The popliteal vein, intimately adherent to the 

 artery, lies to the outer side above, but crosses to its inner side below. The walls 

 of this vein are thicker and denser than those of any other vein (Tillaux). The 

 popliteal sheath is also unusually strong. The internal popliteal nerve crosses the 

 artery in the same direction as the vein by which it is separated from the artery. 

 This'nerve is the direct continuation of the great sciatic nerve (fig. 753). 



The superior articular arteries course outwards and inwards immediately 

 above the condyles; the inferior ones lie just above the head of the fibula and 

 below the internal tuberosity of the tibia (fig. 756). The deep part of the anasto- 

 motic artery runs in front of the tendon of the adductor magnus; the superficial 

 with the internal saphenous nerve. 



Fig. 753. — Deep View of the Popr,iTEAi. Space. (Hirsclifeld and Leveille.) 



Adductor magnus yj 



Popliteal Tfiii 



Popliteal artei ii 



INTERNAL POPLITEAL NERVl 



Vastus internus 



Superior internal articular artei i 



Tendon of semi-membranosus 



Inner head of gastrocnemius J^f — ] 



Inferior internal articular artfi v 

 Popliteal vmi 



Popliteua "^J' 



Tendon of plantari 



'iTO Vastus externus 



GPEA T SCIA TIC NER VE 



hort head of biceps 



'-EXTERNAL POPLITEAL NERVE 



Long head of biceps, cut 

 Outer head of gastrocnemius 



r ( <> VMUNICANS PERONEI NER VE 



ibtrocnemiuB 



External saj)he_nou-i rein and nerre 



The external saphenous vein perforates the roof of the popliteal space in its 

 lower part. As a rule, it is not visible unless enlarged. 



The popliteal glands are not to be felt unless enlarged. 



Bursae in the popliteal space. — These have been already spoken of (page 

 1187). 



THE LEG 



Bony landmarks. — From the tubercle of the tibia descends the anterior border 

 or 'shin.' This soon becomes sharp, and continues so for its upper two-thirds; 

 in the lower third it disappears, to be overlaid by the extensor tendons. It is 

 curved somewhat outwards above, and inwards below. The inner border can also 

 be felt from the inner tuberosity to the internal malleolus. Between these two 

 borders lies the internal surface, subcutaneous, save above, where it is covered by 

 tlie three tendons of insertion of the gracilis and semi-tendinosus, and, overlying 

 them, that of the sartorius. The tibia is narrowest and weakest at the junction of 



