228 



THE VASCULAR SYSTEM. 



y. The Bami intercostales are distributed in part to the 3IM. in- 

 tertj'ansversarii ; other twigs pass ventrally to the periganglionic 

 glands ; the longest branches accompany the anterior divisions of 

 thfi spinal nerves to the muscles and skin of the belly (Fig. I45)- 

 / (2) ïhe occipital artery [Arteria occipitalis), (Figs. 147 and 148 0), 

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

 31. longissimus dor si ; 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 Hamus orhito-nasalis (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 ojihthalmic 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. 

 13. The Bamns maxillaris communis {Art. temjwralis, Virchow), 

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

 border of the M. temporalis, and passes under the anterior arm of 

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



this point the Bamus maxillaris 

 I'ig- 148- superior [m') is given off. The 



y o on main artery continues its backward 



course to the tympanic membrane, 

 where it divides into its three termi- 

 nal branches : — 



[(i) The Bamns maxillaris supe- 

 rior (AA. maxillares S2(periores, Vir- 

 chow), usually not a single artery 

 but a number of small twigs, which 

 supply the space between the eye 

 and the upper jaw. 



(s) A small ascending branch to 

 the tympanic membrane (Virchow). 



(3) A Bamt(sa?iric?ilaris(Yirchow), 

 which forms a rich anastomosis on 

 the hinder wall of the tympanic 

 cavity, and supplies a twig- to the 

 tympanic membrane. Tliis passes 



Branches of the occipito-vertebral and cuta- 

 neous arteries in the head ; side view. The 

 skin (//) has been reflected downwards. 



cm. Cutaneous artery. 



l.a. M. levator scapulae. 



m Art. maxillaris communis. 



»»' Art. maxillaris superior. 



in" Art. maxillarLs inferior. 



o Occipital artery. 



on Art. orbito-nasalis. 



p.m. Art. pharyngo-maxillaris. 



V Vertebral artery. 



