THE HIND EXTREMITY. 271 



part of the superior extremity of the large metatarsal 

 bone, and thus gains the channel between this bone and 

 the extei'nal small metatarsal, in which it runs subcuta- 

 neously, so that the pulse may be taken here. It passes 

 between the inferior extremity of the small bone and the 

 large bone to gain the posterior part of the inferior third 

 of the latter, where, after giving off the recurrent branch, 

 it bifurcates in passing between the divisions of the supe- 

 rior sesamoideal ligament, forming plantar arteries ana- 

 logous in situation and distribution to those of the fore 

 limb. The recurrent branch passes up the back of the 

 OS metatarsi magnum, protected by the inner small meta- 

 tarsal bone, and at the inferior part of the superior third 

 gives off tlie medullary artery of the large metatarsal hone. It 

 terminates at the supero-internal part of the hock, by anas- 

 tomosing with the posterior tibial at its sigmoid flexure. 



The superficial metatarsal vein runs on the inner sur- 

 face of the limb in the groove between the large and inner 

 small metatarsal bones. At the front of the hock it bifur- 

 cates ; one branch runs on to the internal surface of the 

 tibia, forming the commencement portion of the vena 

 saphena, the other, by uniting with a large branch running- 

 from between the bones of the hock, forms the anterior 

 tibial veins, generally two in number, one of them beings 

 enlarged, the varicose vein of the thigh, they pass with the 

 artery of the same name. The deep-seated metatarsal 

 veins divide superiorly ; one division forming the inter^ 

 osseous branch, which passes between the bones of the hock 

 to assist in forming the anterior tibial, the other passincr 

 through the groove of the calcis to form the posterior 

 tibial veins, which accompany the arteries of the same 

 name up the back of the til3ia. 



Just above the commencement of the gastrocnemii 

 muscles the sacro- sciatic nerve terminates in breaking 

 up to form the anterior and posterior tibial, and pojAiteal 

 nerves. The popliteal proceeds down the back of the 

 limb, and dips between popliteus and the flexors, which 

 it supplies with nerve force. The anterior tibial passes 

 over the external head of gastrocnemius externus and 

 peroneus to gain the muscles in front of the tibia It 

 thus presents a marked difference in its course as com- 

 pared with that of the artery and vein of the same 

 name. It is sometimes divided at its superficial part by 



