562 ANGIOLOGY 



The Posterior Superior Alveolar Artery (a. alveolaris superior posterior; alveolar or 

 posterior dental artery) is given off from the internal maxillary, frequently in con- 

 junction with the infraorbital just as the trunk of the vessel is passing into the 

 pterygopalatine fossa. Descending upon the tuberosity of the. maxilla, it divides 

 into numerous branches, some of which enter the alveolar canals, to supply the 

 molar and premolar teeth and the lining of the maxillary sinus, while others are 

 continued forward on the alveolar process to supply the gums. 



The Infraorbital Artery (a. infraorbitalis) appears, from its direction, to be the 

 continuation of the trunk of the internal maxillary, but often arises in conjunction 

 with the posterior superior alveolar. It runs along the infraorbital groove and 

 canal with the infraorbital nerve, and emerges on the face through the infraorbital 

 foramen, beneath the infraorbital head of the Quadratus labii superioris. While 

 in the canal, it gives off (a) orbital branches which assist in supplying the Rectus 

 inferior and Obliquus inferior and the lacrimal sac, and (6) anterior superior alveolar 

 branches which descend through the anterior alveolar canals to supply the upper 

 incisor and canine teeth and the mucous membrane of the maxillary sinus. On 

 the face, some branches pass upward to the medial angle of the orbit and the 

 lacrimal sac, anastomosing with the angular branch of the external maxillary 

 artery; others run toward the nose, anastomosing with the dorsal nasal branch of 

 the ophthalmic; and others descend between the Quadratus labii superioris and 

 the Caninus, and anastomose with the external maxillary, transverse facial, and 

 buccinator arteries. The four remaining branches arise from that portion of the 

 internal maxillary which is contained in the pterygopalatine fossa. 



The Descending Palatine Artery (a. palatina descendens) descends through the 

 pterygopalatine canal with the anterior palatine branch of the sphenopalatine 

 ganglion, and, emerging from the greater palatine foramen, runs forward in a groove 

 on the. medial side of the alveolar border of the hard palate to the incisive canal; 

 the terminal branch of the artery passes upward through this canal to anastomose 

 with the sphenopalatine artery. Branches are distributed to the gums, the palatine 

 glands, and the mucous membrane of the roof of the mouth; while in the pterygo- 

 palatine canal it gives off twigs which descend in the lesser palatine canals to supply 

 the soft palate and palatine tonsil, anastomosing with the ascending palatine artery. 



The Artery of the Pterygoid Canal (a. canalis pterygoidei; Vidian artery] passes 

 backward along the pterygoid canal with the corresponding nerve. It is distributed 

 to the upper part of the pharynx and to the auditory tube, sending into the tympanic 

 cavity a small branch which anastomoses with the other tympanic arteries. 



The Pharyngeal Branch is very small; it runs backward through the pharyngeal 

 canal with the pharyngeal nerve, and is distributed to the upper part of the pharynx 

 and to the auditory tube. 



The Sphenopalatine Artery (a. sphenopalatina; nasopalatine artery) passes through 

 the sphenopalatine foramen into the cavity of the nose, at the back part of the 

 superior meatus. Here it gives off its posterior lateral nasal branches which spread 

 forward over the conchae and meatuses, anastomose with the ethmoidal arteries 

 and the nasal branches of the descending palatine, and assist in supplying the 

 frontal, maxillary, ethmoidal, and sphenoidal sinuses. Crossing the under surface of 

 the sphenoid the sphenopalatine artery ends on the nasal septum as the posterior 

 septal branches; these anastomose with the ethmoidal arteries and the septal 

 branch of the superior labial; one branch descends in a groove on the vomer to 

 the incisive canal and anastomoses with the descending palatine artery. 



THE TRIANGLES OF THE NECK (Fig. 512). 



The side of the neck presents a somewhat quadrilateral outline, limited, above, 

 by the lower border of the body of the mandible, and an imaginary line extending 





