CAROTID ARTERY. 



489 



frontal branches of the ophthalmic and with 

 the opposite temporal. The posterior branch 

 passes upwards and backwards in a tortuous 

 course, and supplies the integuments, tem- 

 poral aponenrosis, pericranium, &c. These 

 branches anastomose with the anterior branch, 

 with the opposite temporal, the occipital, and 

 posterior auris. 



'2. The internal maxillary artery, (a. maxil- 

 laris interna^) is larger than the preceding; im- 

 mediately after its origin it passes downwards 

 and inwards under the neck of the condyle of 

 the lower jaw; it then mounts forwards and in- 

 wards between the temporal and external ptery- 

 goid muscles, and usually passing between the 

 two origins of the latter, it enters the pterygo- 

 maxillary fossa, where it ascends as high as 

 the level of the inferior wall of the orbit, oppo- 

 site which it takes a horizontal direction. At 

 this place it divides into numerous branches, 

 which are distributed on one side inwards to- 

 wards the nose, and on the other side to the 

 external part of the face. 



The branches of the internal maxillary are, 

 a. the middle meningeal, b. the inferior dental, 

 c. the posterior deep temporal, d. the masseteric, 

 e. pterygoid branches, f. the. buccal, g. the an- 

 terior deep temporal, h. the alveolar, i. the 

 infra-orbital, 1. the superior palatine, m. the 

 vidian, n. the pterygo-palatine, and o. the 

 spheno-palatine : in addition to these the in- 

 ternal maxillary artery gives several branches to 

 the cellular tissue and other parts surrounding it. 



a. The middle mcningeal artery (a. meningea 

 media, spinom) arises from the superior part of 

 the artery and passes directly upwards on the 

 inside of the external pterygoid muscle, to 

 which, to the superior constrictor of the pharynx 

 and muscles of the velum palati it sends 

 branches, and passing between the tensor 

 palati muscle and internal lateral ligament of 

 the temporo-maxillary articulation, enters the 

 cranium through the foramen spinale of the 

 sphenoid bone, and immediately gives off some 

 small branches, which pass through the hiatus 

 Fallopii to the cavity of the tympanum, where 

 they anastomose with the stylo-mastoid artery; 

 other branches pass forwards towards the orbit 

 into which some of them occasionally enter by 

 the foramen lacerum. The meningeal artery 

 then divides into two branches, an anterior and 

 a posterior ; the anterior, which is the larger, 

 might be considered as the continued trunk; it 

 mounts forwards towards the anterior inferior 

 angle of the parietal bone, where it is lodged in 

 a groove, and sometimes in a canal in the sub- 

 stance of that bone. This branch at first gives 

 twigs to the foramen lacerum, which anastomose 

 with the lachrymal ; after which it mounts on 

 the parietal bone, principally following the 

 course of the coronal suture, sending its bran- 

 ches upwards and backwards between the dura 

 mater and the inner surface of the parietal 

 bone. The posterior branch passes backwards 

 in a curved direction on the inner surface of the 

 squamous portion of the temporal bone, and 

 advancing towards the inferior border of the 

 parietal bone, is expended on the posterior and 

 lateral part of the dura mater. The branches 



of the middle meningeal artery spread over the 

 external surface of the dura mater, and occupy 

 the grooves which are disposed in an arbores- 

 cent form on the internal surface of the parietal 

 bone. The middle meningeal artery anasto- 

 moses with that of the opposite side and with 

 the other arteries of the dura mater. 



b. The inferior maxillary or inferior dental 

 artery sometimes coming from the middle me- 

 ningeal, descends to the posterior dental hole 

 by which it enters the dental canal, passing be- 

 tween the inner surface of the ramus of the jaw 

 and the outer surfaces of the internal pterygoid 

 muscle and the internal lateral ligament of the 

 temporo-maxillary articulation, to which it gives 

 small twigs : before it enters the dental hole, it 

 gives off a small branch, which passing down- 

 wards and forwards in a groove on the inside 

 of the lower jaw, is distributed to the mylo- 

 hyoid muscle and mucous membrane of the 

 mouth. In the dental canal this artery passes 

 forwards beneath the alveoli of the molar teeth, 

 sending upwards in its course several branches 

 which penetrate into the alveoli, and enter the 

 cavities of the teeth by the holes in their roots ; 

 having arrived opposite the mental hole, it 

 sends a branch which passes onwards beneath 

 the alveoli of the canine and incisor teeth, to 

 which it is distributed ; while the continuation 

 of the artery coming out through the mental 

 hole is distributed to the muscles of the lower 

 lip, where it anastomoses with the labial. 



c. The posterior deep temporal artery arises 

 after the dental ; it passes upwards between the 

 temporal and external pterygoid muscles, and 

 sinking into the substance of the former, divides 

 into a great number of branches, which spread 

 over the squamous portion of the temporal 

 bone, and are distributed to the temporal mus- 

 cle and pericranium. This artery anastomoses 

 with the anterior deep temporal, the middle, 

 and the superficial temporal. 



d. The masseteric is a small branch often 

 arising from the posterior deep temporal; it 

 passes outwards between the posterior border 

 of the temporal muscle and the condyle of the 

 lower jaw, and enters the masseter muscle, 

 where it anastomoses with the transversalis 

 faciei. 



e. The pterygoid arteries are irregular as to 

 number, size, and origin; they either come 

 from the trunk of the internal maxillary or the 

 posterior deep temporal, and are distributed to 

 the pterygoid muscles. 



J\ The buccal artery does not always arise 

 from the internal maxillary itself; it sometimes 

 comes from the anterior deep temporal, the 

 alveolar, or infra-orbital. It passes downwards 

 and forwards between the internal pterygoid 

 muscle and ramus of the lower jaw, and ad- 

 vances over the surface of the buccinator mus- 

 cle, to which it gives branches, as well as to the 

 zygomatic and other muscles of the lip : it 

 anastomoses with the labial, infra-orbital, and 

 transversalis faciei. 



g. The anterior deep temporal arises from 

 the internal maxillary, near the outer wall of 

 the temporal fossa beneath the temporal mus- 

 cle, to which it is distributed ; some of its 



