238 THE VASCULAR SYSTEM. 



wards under cover of the tendon of the M. Weeps femoru, and 

 accompanies the peroneal nerve downwards to give off : — 



a. The Art. ciraimjlexa genu lateralis superior, which runs forwards 

 on the outer side of the knee, gives a twig" to the joint, and is 

 continued as : — 



b. The Art. cutanea genu lateralis superior [cgl) to the skin of the 

 anterior and outer sides of the knee. It anastomoses with branches 

 of the Arteriae circumjlexae genu vierliales to form a rich anastomosis 

 [Rete articnlare genu) : other branches pass upwards to inosculate 

 with the Art. cutanea femoris anterior {cf), and others downwards 

 to anastomose with the next artery. 



c. The Art. circumfiexa genu lateralis inferior {cgl') runs under 

 the tendon of origin of the gastrocnemius to the outer side of the 

 knee, and terminates in the skin as the Art. cutanea genu lateralis 

 inferior. Some of the cutaneous twigs pass upwards to anastomose 

 with the Art. cut. gemi lat. superior, others downwards to anastomose 

 with the AA. malleolares. 



d. A muscular branch [p') for the M. peroneus ; it is the real 

 continuation of the peroneal artery, and runs behind the outer 

 tendon of origin of the gastrocnemius to be distributed in the 

 3f. peroneus. 



C. The tibial artery (Arteria tihialis), (Fig. 156 t), arises at 

 the bifurcation of the sciatic, and runs inwards, meeting the 

 tibial nerve between the tendons of origin of the M. gastrocnemius, 

 and deep in the popliteal space under cover of the calf -muscles. It 

 then pierces the M. tibialis pjosticus, and leaves this to perforate the 

 tibio-fibula (see p. 50), appearing again on the anterior surface 

 as the anterior tibial artery. Before meeting the tibial nerve this 

 artery gives off the following branches : — 



a. The Art. circuwjlexa genu superior medialis [cgvi), which winds 

 round to the front of the knee-joint, and gives off a cutaneous 

 branch, the Art. cutanea gemi medialis siiperior, which is distributed 

 in the skin of the inner side of the knee and anastomoses above with 

 the Art. cutanea femoris media, below with the following branches 

 (b, c, and d). 



b. The Art. circumjîexa genu inferior medialis {cgm') supplies twigs 

 to the knee-joint, and passes to the skin of the knee and inner 

 surface of the calf as the Art. cutanea inferior medialis. 



e. Musciilar twigs to the M. gastrocnemius. 



