410 



THE ARTERIES OF THE HEAD AND NECK. 



brane of the posterior ethmoidal cells and upper part of the nose. The anterior is 

 larger, and passes with the nasal nerve into the cranial cavity, where it gives off small 

 anterior meningeal branches to the dura mater in the anterior fossa, and then 

 descends into the nose (anterior nasal artery). It supplies the mucous membrane of 

 the fore part of the nasal fossa, frontal sinus and anterior ethmoidal cells, and one 

 small twig accompanies the termination of the nasal nerve to the skin of the nose. 



(h) The two palpelral branches, superior and inferior, arise near the front of the 

 orbit, usually together, but soon diverge, one lying above, the other below the 



Fig. 345. SEMIDIAGRAMMATIO VIEW OP THE ARTERIES OP THE ORBIT AND NEIGHBOURING PARTS, WITH 



THEIR BRANCHES AND ANASTOMOSES. (Allen Thomson. ) 



The outer wall of the orbit has been removed, the maxillary sinus is laid open, the eyelids are turned 

 forwards, and the external and superior recti, and the superior oblique muscles have been partially 

 removed : a, optic nerve ; b, hook, holding up the posterior part of the superior rectus muscle, the 

 anterior part of which is left attached to the eyeball ; c, lachrymal gland, thrown up on the frontal 

 bone ; d, inferior oblique muscle ; e, inferior rectus ; /, /, anterior and posterior portions of the 

 external rectus ; g, maxillary sinus ; A, hook, holding up the eyelids, of which the deep surface is 

 shown. 



I, internal carotid artery below the inferior aperture of the carotid canal, which is indicated higher 

 up by a ring surrounding the artery ; 1', the part of the artery situated within the temporal bone, a 

 second ring indicating the place of the foramen lacerum ; 1", the part of the artery situated on the 

 sphenoid bone ; from this artery, 1, twig to the tympanum ; 2, twigs in the cavernous sinus ; 3, pos- 

 terior communicating artery ; 4, middle cerebral ; 5, anterior cerebral. 



II, basilar artery ; from 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, which with these and the anterior communicating branch marked by + , 

 complete the circle of Willis. 



III, upper part of the external carotid artery, dividing into III +, the superficial temporal, and 

 III', III", the internal maxillary artery ; from the latter artery, 1, inferior dental branch ; 2, middle 

 meningeal ; 3, 3, masseteric and pterygoid branches ; 4, buccal ; 5, 5, anterior and posterior deep 

 temporal ; 6, posterior dental ; 7, infraorbital ; 7', branches of the same issuing upon the 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 off, at 12, the lateral nasal branch, 

 and others which communicate with the infraorbital. 



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

 ophthalmic at its origin from the internal carotid ; 1', the same artery continued on the upper and 

 inner side of the orbit ; 2, lachrymal ; 3, central artery of retina ; 4, 4, posterior ciliary ; 5, 5, muscular ; 

 6, supraorbital ; 7, 7', posterior and anterior ethmoidal ; 8, 8', 8", palpebral ; 9, frontal ; 10, nasal, 

 inosculating with the angular of the facial. 



