1'OSTERIOK PART 01- I.0\\'l:l< EXTREMITY. 



367 



]\'liv this rclat'mn of artery and rein .' 



The rule is : Veins arc behind their arteries below tin: diaphragm, and in 

 front of them above the diaphragm where they are not on the same plane. 

 Exception to rule : the renal vessels. 



What can you say about tin internal popliteal nerve .' (Fig. 266.) 



It begin* at the bifurcation of the great sciatic, and ends at the lower border 

 of the popliteal space, where its continuation through the leg is called posterior 

 tibial. In its course it throws off these branches : 



I. The communicans tibialis or communicans poplitei. 



LAST 

 THORACIC 



II.Ht-IIYI'O- 

 OASTRIC 



F.XTl'.KSM. 

 CUTAX&H-.-i 



POSTERIOR 

 UK A .vi ;/>:. 

 OF LrUHAB, 



XEnrss 



POSTERIOR 

 BSAXCHKS 

 I if "VRAL 



xesrta 



PERFORA TlX'l 



ctTTAitEOCS of 



f.-fi-n\-i, i.\;i 



THIRD SACRAL 



Lone 



PCDEKDAL 



BRAXCHS3 Of 

 SMALL 

 SCIA TIC 



OBTURATOR 



POSTRRIOB 

 BKAXCH Of 

 IXTKRXAL 

 Cl-TAXKOUS 



coimrxr- 



rj.vx 



TIBIALIS 



TWir.S FRO.V 



KffORT 

 8APIIEXOUS 



I\TER\AL 

 CALCAXEAX 



FIG. 255. DISTRIBUTION OF CUTANEOUS NERVKS ON THE POSTERIOR ASPECT OF THE 



INFERIOR EXTREMITY. 



2. Three articular branches to the knee-joint. 



3. Muscular branches to the gastrocnemius, soleus, plantaris, popliteus. 

 The articular brandies reacli the knee-joint //".v ' 



One goes with the azygos artery, and two accompany the internal articular 

 arteries, superior and inferior. 



Describe the external popliteal nerre. 



It begins at the bifurcation of the great sciatic, is found in the outer side of the 

 p ipliteal space in the sheath of the biceps muscle. It leaves the space between 

 the biceps and the outer head of the gastrocnemius muscle. It crosses the neck 

 of the fibula, having passed behind the head of this bone, and terminates in the 

 anterior tibial and musculo-cutaneous nerves. In its course it gives off these 



