376 



AETEEIES OF THE HEAD AND NECK. 



arteries having fumislied brandies to the ethmoidal cells, enter the skull, supply 

 the adjacent dura mater, and send branches through the cribriform lamella to 

 the nose. 



Fig. 253. 



Fig. 253. — Semidiagrammatic View of the Arteries of the Orbit and KEiGiinoun- 

 iNG parts, with their BRANCHES AND AN.ASTOMOSEs (fouuded ou Hirschfekl and 

 Leveille, with aJJitious). (A. T. ) 



The outer wall of tlie orLit has been removed, the sinus maxillaris is laid open, tlie 

 eyelids ai-e turned forwards, and the external and superior recti, and the superior obhquc 

 muscles have been jiartially removed, a, optic nerve ; h, liooic, holding up the posterior 

 part of the superior rectus muscle, the anterior part of wliicli is left attached to the 

 eyeball ; c, laclirymal gland, thrown up on the frontal bone ; d, insertion of the inferior 

 oblique muscle ; e, inferior rectus ; /, /, anterior and jjosterior portions of the divided 

 external rectus ; g, maxillary sinus ; h, hook, holdiug \\\) the eyelids, of which the deep 

 surface is exhibited. 



I, internal carotid artery below the inferior aperture of the carotid canal of the 

 temporal bone, which is indicated higlier up by a ring surrounding the artery ; 1', tlie 

 part of the artery situated within the temporal bone, a second ring indicating the place 

 of the upper aperture of tlie temporal canal ; 1", the part of the artery situated on the 

 .sphenoid bone ; upon this artery, 1, twig to the mastoid cells and tymi)anum ; 2, twigs 

 in the cavernous sinus ; 3, communicating branches to the iwsterior cerebral ; 4, middle 

 cerebral ; 5, anterior cerebral. 



II, basilar artery ; upon this artery, 6, posterior cerebral ; 7, superior cerebellar : the 

 accented numbers, 3', 4', 5', 6', 7', indicate, on the left side, the arteries already named 

 under the same numbers on the right side, and with these and the anterior communicating 

 branch marked by + , complete the Circle of Willis. 



III, upper part of the external carotid arterj' dividing into III x , the superficial 

 temporal, and III', III", the internal maxillary artery ; upon the latter artery, 1, inferior 

 dental branch ; 2, middle meningeal ; 3, 3, masseteric and pterygoid branches ; 4, buccal ; 

 f), 5, anterior and posterior deep temporal ; 6, posterior superior dental ; 7, infraorbital ; 

 7', branches of the same issuing upon tlie face ; 8, part of the internal maxillary, which 

 passes into the spheno-maxillary fossa. 



IV, facial artery, terminating at 11, in the angular, and giving oflF, at 12, the lateral 

 nasal branches, and others which communicate with the infraorbital. 



In the orbit the following numbers indicate the ophthalmic artery and its branches : 1, 



