FACE AND FRONTAL REGION OF HEAD 131 



of the mouth and runs medially in the upper lip, between 

 the orbicularis oris and the mucous membrane. Before it 

 anastomoses with its fellow of the opposite side, it gives off 

 a branch, the septal artery of the nose, which passes upwards 

 and ramifies on the lower and anterior part of the nasal septum, 

 where it anastomoses with the septal branch of the spheno- 

 palatine artery. 



The Angular Artery. This is the continuation of the 

 external maxillary beyond the point of origin of the lateral 

 nasal branch. It runs upwards in the substance of the 

 angular head of the quadratus labii superioris, and it 

 terminates at the medial commissure of the eye by anastomos- 

 ing with the nasal branch of the ophthalmic. The lateral 

 nasal branch springs from the external maxillary at the point 

 where it becomes the angular. It ramifies on the side of the 

 nose and anastomoses in the median plane with its fellow of 

 the opposite side. 



In addition to the branches already noted, a very definite 

 branch is usually given off from the anterior aspect of the 

 external maxillary artery 'immediately after it crosses the 

 lower border of the mandible. This branch (O.T. inferior 

 labial) runs towards the median plane under cover of the 

 triangularis and the depressor labii inferioris, and it anasto- 

 moses not only with the inferior labial (O.T. inferior coronary) 

 above, and its fellow of the opposite side in the median plane, 

 but also with the mental branch of the inferior alveolar artery. 



Vena Facialis Anterior (O.T. Facial). The anterior 

 facial vein is a less tortuous vessel than the external maxillary 

 artery to which it corresponds, and it lies posterior, and on 

 a slightly more superficial plane. It commences as the 

 angular vein, which is formed at the medial commissure 

 of the eyelids, by the union of the frontal and supra-orbital 

 veins, which descend from the forehead. It passes down- 

 wards and posteriorly, in a comparatively straight line, to the 

 anterior inferior angle of the masseter, which it crosses 

 immediately behind the external maxillary artery; then it 

 pierces the deep fascia of the neck, and enters the sub- 

 maxillary triangle. In the upper part of the face it lies on 

 the quadratus labii superioris ; then it is situated between the 

 zygomaticus and the risorius superficially and the buccinator 

 deeply ; and as it crosses the anterior angle of the masseter 

 it is covered with the skin, superficial fascia, and the platysma. 

 ii 9 a 



