228 



THE VASCULAR SYSTEM. 



y. The Kami intercostales are distributed in part to the MM. in- 

 tertransversarii ; other twigs pass ventrally to the periganglionic 

 glands ; the longest branches accompany the anterior divisions of 

 the spinal nerves to the muscles and skin of the belly (Fig. 145). 



(a) The occipital artery (Artena occipitalis], (Figs. 147 and 148 o), 

 the anterior branch of the occipito-vertebral artery, pierces the 

 M. longissimus dorsi ; then courses forwards under cover of the 

 Fascia dorsalis and upon the M. temporalis, and divides, behind the 

 eyeball [at the anterior border of the M. temporalis, Virchow], 

 into two branches : 



a. The Ramus orlito-namlis (Fig. 148 on) accompanies the oph- 

 thalmic nerve along the wall of the cranium, and passes through 

 the sphenethmoid, with the nasal branch of the ophthalmic nerve, to 

 the nose, where it divides into two branches supplying the mucous 

 membrane of the nose. In its course through the orbit the artery 

 supplies branches to the Harderian gland and neighbouring parts, 

 and anastomoses with the ascending branch of the Arteria palatina. 

 ft. The Ramus maxillaris communis (Art. temporalis, Virchow), 

 (Fig. 148 m) runs downwards and outwards along the anterior 

 border of the M. temper all* } and passes under the anterior arm of 

 the squamosal bone to coiirse backwards on the upper jaw. At 



this point the Ramus maxillaris 

 Fi g- J 4 8 - superior (m'} is given off. The 



v O n main artery continues its backward 



course to the tympanic membrane, 

 where it divides into its three termi- 

 nal branches : 



[(i) The Ramus maxillaris supe- 

 rior (AA. maxiflares guperiores, Vir- 

 chow), usually not a single artery 

 but a number of small twigs, which 

 supply the space between the eye 



Branches of the occipito-vertebral and cuta- and the Upper "jaw. 



(2) A small ascending branch to 

 the tympanic membrane (Virchow). 



(3) A Ramus a uricularis( Virchow), 

 which forms a rich anastomosis on 

 the hinder wall of the tympanic 

 cavity, and supplies a twig to the 

 tympanic membrane. This 



neons arteries in the head ; side view. The 

 skin (77) has bsen reflected downwards. 



c.tn 



l.fi. 



Cutaneous artery. 



M. levator scapulae. 

 in Art. maxillaris communis. 

 HI' Art. maxillaris superior. 

 m" Art. maxillaris inferior. 

 o Occipital artery. 

 on Art. orbito-nasalis. 

 p.m. Art. pharyngo-maxillaris. 

 v Vertebral artery. 



