356 EXTERNAL CAROTID ARTERY. 



BRANCHES. A. Branches of the first part. The branches of the first 

 part of the artery all pass through osseous foramina. 



(a) The tympanic branch, of small size and variable in origin, passes deeply behind 

 the articulation of the lower jaw, and enters the fissure of Glaser, supplying the 

 laxator tympani muscle, and the tympanic cavity, where it ramifies upon the 

 membrana tympani. It anastomoses in the tympanum with the stylo-mastoid and 

 Vidian arteries. 



(b) The middle or great meningeal artery, by far the largest of the arteries which 

 supply the dura mater, passes directly upwards under cover of the external ptery- 

 goid muscle, and enters the skull by the spinous foramen of the sphenoid bone. 

 Within the cranium, it ascends to the anterior inferior angle of the parietal bone, and 

 divides into numerous branches, which ramify in deep arborescent grooves on the 

 inner surface of the bones, some passing upwards over the parietal bone as high as the 

 vertex, and others backwards even to the occipital bone. 



Immediately on entering the cranium, the meningeal artery gives minute branches 

 to the ganglion of the fifth nerve and to the dura mater near the sella turcica, and a 

 small twig which enters the hiatus Fallopii, and anastomoses with the stylo-mastoid 

 branch of the posterior auricular artery. It also inosculates with branches of the 

 ophthalmic artery. 



The middle meningeal artery is accompanied by two veins. 



(c) The small meningeal artery, usually arising faom the preceding branch, 

 enters the skull through the foramen ovale, to supply the dura mater in the middle 

 fossa. 



(d) The inferior dented artery, passing downwards, enters the dental canal along 

 with the inferior dental nerve, and subsequently escapes on the face by the mental 

 foramen. As it enters the canal, it gives off the mylo-hyoid branch, which, with the 

 nerve bearing the same name, runs in a groove on the inner surface of the jaw, 

 below the dental foramen, and ramifies on the under surface of the mylo-hyoid 

 muscle. In its course through the bone, the inferior dental artery gives off small 

 offsets, which ascend to enter the minute apertures in the extremities of the fangs of 

 the teeth, and supply the pulp of each ; and, before emerging at the mental foramen, 

 it sends forwards a branch which supplies the incisor teeth and inosculates with its 

 fellow of the opposite side. The terminal or facial branches anastomose with the 

 inferior coronary and submental arteries. 



B. Brandies of the second part. The branches of this part are chiefly 

 distributed to muscles, and are named muscular. 



(a) The deep temporal branches, two in number (anterior and posterior), ascending 

 between the temporal muscle and the cranium, supply that muscle, and anastomose 

 with the branches of the other temporal arteries, and with minute branches of the 

 lachrymal artery, through small foramina in the malar bone. 



(b) The pterygoid branches, small short offsets, irregular in number and origin, 

 are distributed to the pterygoid muscles. 



(c) The masseteric is a small but regular branch which passes from within out- 

 wards, above the sigmoid notch of the lower maxillary bone, to the deep surface of 

 1 he masseter muscle. It is often joined at its origin with the posterior temporal 

 branch. 



(d) The buccal branch runs obliquely forwards upon the buccinator muscle with 

 the buccal nerve ; it is distributed to that and other muscles of the cheek, and anas- 

 tomoses with the branches of the facial artery. 



C. Branches of the third part. These branches, like those of the first 

 series, enter bony foramina or canals. 



(a) The alveolar or superior maxillary branch, arising near the tuberosity of the 

 maxillary bone, frequently in common with the infraorbital branch, runs tortuously 

 forwards upon the surface of the upper jaw, and gives off the superior dental and 

 other branches which enter the foramina of the tuberosity, and supply the pulps of 



