148 



VEINS OF THE HEAD AND NECK. 



supplies the outer side of the great toe and 

 Fig. 129. the inside of the second toe. . 



Pedal.^^ — This branch forms the commu- 

 nication between the anterior tibial and 

 external plantar arteries. It descends to 

 the sole of the foot, through the first inter- 

 osseous muscle. 



PLANTAR. 



These arteries are branches of the pos- 

 terior tibial,^ which reach the sole of the 

 foot, through the sinuosity of the os calcis. 



External 'pla7itar P — This is the larger of 

 the two, and passing obliquely outwards 

 upon the sole of the foot, it forms a deep 

 arch^ above the muscles of the foot. From 

 it are given off digital arteries for the supply 

 of the interosseous spaces, and which, bifur- 

 cating into the external and internal branches, 

 supply the toes. The external plantar ter- 

 minates in the pedal artery. 



Internal plantar.^ — This is a small 

 artery, which passes along the inner border 

 of the foot, and terminates in the digital artery of the great toe. 



VEINS. 



The veins return the blood to the heart. They are much more 

 numerous than the arteries ; the deep arteries having two accom- 

 panying veins called ve72{^ comites. Their walls have the three 

 coats, but they are much thinner than the arteries ; this deficiency, 

 particularly in the middle elastic coat, gives them a flaccid appear- 

 ance when empty, whereby they can be readily distinguished from 

 arteries, which retain their cylindrical character. 



They differ from arteries also, in having numerous valves opening 

 towards the heart, which are more numerous in the superficial 

 veins. 



These valves are formed of two or three crescentic folds of the 

 lining membrane, and give the veins a knotty appearance when 

 injected. 



Sinuses are channels conveying venous blood and lined by the 

 internal coat of the veins. 



The distribution and anastomoses of the veins are much more irre- 

 gular than those of the arteries. 



VEINS OF THE HEAD AND NECK. 



The venous blood from the face is for the most part collected by 

 veins accompanying the arteries, and which have the same name. 



