INTERNAL MAXILLARY. 45T 



merit and the neck of the jaw, and passes vertically upwards to the foramen 

 spinosum of the sphenoid bone. On entering the cranium, it divides into two 

 branches, anterior and posterior. The anterior branch, the larger, crosses the 

 great ala of the sphenoid, and reaches the groove, or canal, in the anterior 

 inferior angle of the parietal bone ; it then divides into branches, which spread 

 out between the dura mater and internal surface of the cranium, some passing 

 upwards over the parietal bone as far as the vertex, and others backwards to 

 the occipital bone. The posterior branch crosses the squamous portion of the 

 temporal, and on the inner surface of the parietal bone divides into branches, 

 which supply the posterior part of the dura mater and cranium. The branches 

 of this vessel are distributed partly to the dura mater, but chiefly to the bones; 

 they anastomose with the arteries of the opposite side, and with the anterior 

 and posterior meningeal. 



The middle meningeal, on entering the cranium, gives off the following col- 

 lateral branches : 1. Numerous small vessels to the ganglion of the fifth nerve, 

 and to the dura mater in this situation. 2. A branch to the facial nerve, which 

 enters the hiatus Fallopii, supplies the facial nerve, and anastomoses with the 

 stylo-mastoid branch of the posterior auricular artery. 3. Orbital branches, 

 which pass through the sphenoidal fissure, or through separate canals in the 

 great wing of the sphenoid, to anastomose with the lachrymal or other branches 

 of the ophthalmic artery. 4. Temporal branches, which pass through foramina 

 in the great wing of the sphenoid, and anastomose in the temporal fossa with 

 the deep temporal arteries. 



The small meningeal is sometimes derived from the preceding. It enters the 

 skull through the foramen ovale, and supplies the Casserian ganglion and dura 

 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 sub- 

 stance of the bone, accompanied by the nerve, and opposite the first 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 anasto- 

 moses 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 cancellous 

 tissue, and a series of branches which correspond in number to the roots of 

 the teeth ; these enter the minute apertures at the extremities of the fangs, and 

 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 be- 

 tween the Temporal muscle and pericranium, they supply that muscle, and 

 anastomose with the other temporal arteries; the anterior branch communi- 

 cating with the lachrymal through small branches, which perforate the malar 

 bone, 



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

 Pterygoid muscles. 



