INTERNAL MAXILLARY. 381 



mater. Before entering the cranium, it gives off a branch to the nasal fossa and 

 soft palate. 



The inferior dental descends with the dental nerve, to the foramen on the inner 

 side of the ramus of the jaw. It runs along the dental canal in the substance of 

 the bone, accompanied by the nerve, and opposite the bicuspid tooth divides into 

 two branches, incisor and mental ; the former is continued forwards beneath the 

 incisor teeth as far as the symphysis, where it anastomoses with the artery of the 

 opposite side ; the mental branch escapes with the nerve at the mental foramen, 

 supplies the structures composing the chin, and anastomoses with the submental, 

 inferior labial, and inferior coronary arteries. As the dental artery enters the 

 foramen, it gives off a mylo-hyoid branch, which runs in the mylo-hyoid groove, 

 and ramifies on the under surface of the Mylo-hyoid muscle. The dental and 

 incisor arteries, during their course through the substance of the bone, give off 

 a few twigs which are lost in the diploe, and a series of branches which corre- 

 spond in number to the roots of the teeth ; these enter the minute apertures at 

 the extremities of the fangs, and ascend to supply the pulp of the teeth. 



2. Branches of the Second or Pterygoid Portion. 



Deep temporal. Masseteric. 



Pterygoid. Buccal. 



These branches are distributed, as their names imply, to the muscles in the 

 maxillary region. 



The deep temporal branches, two in number, anterior and posterior, each occupy 

 that part of the temporal fossa indicated by its name. Ascending between the 

 Temporal muscle and pericranium, they supply that muscle, and anastomose with 

 the other temporal arteries ; the anterior branch communicating with the lach- 

 rymal through small branches which perforate the malar bone. 



The pterygoid branches, irregular in their number and origin, supply the Ptery- 

 goid muscles. 



The masseteric is a small branch which passes outwards above the sigmoid 

 notch of the lower jaw, to the deep surface of the Masseter. It supplies that 

 muscle, and anastomoses with the masseteric branches of the facial and transverse 

 facial arteries. 



The buccalis a small branch which runs obliquely forwards between the Internal 

 pterygoid and the ramus of the jaw, to the outer surface of the Buccinator, to 

 which it is distributed, anastomosing with branches of the facial artery. 



3. Branches of the Third or Spheno-maxillary Portion. 



Alveolar. Vidian. 



Infra-orbital. Pterygo-palatine. 



Posterior or Descending palatine. Nasal or Spheno-palatine. 



The alveolar is given off from the internal maxillary by a common branch with 

 the infra-orbital, and just as the trunk of the vessel is passing into the spheno- 

 maxillary fossa. Descending upon the tuberosity of the superior maxillary bone, 

 it divides into numerous branches ; one, the superior dental, larger than the rest, 

 supplies the molar and biscuspid teeth, its branches entering the foramina in 

 the alveolar process ; some branches pierce the bone to supply the lining of the 

 antrum, and others are continued forwards on the alveolar process to supply the 

 gums. 



The infra-orbital appears, from its direction, to be the continuation of the trunk 

 of the internal maxillary. It arises from that vessel by a common trunk with 

 the preceding branch, and runs along the infra-orbital canal with the superior 

 maxillary nerve, emerging upon the face at the infra-orbital foramen, beneath the 

 Levator labii super ions. Whilst contained in the canal, it gives off branches 

 which ascend into the orbit, and supply the Inferior rectus, and Inferior oblique 



