THE INTERNAL CAROTID ARTl 



on the forehead, supplies the integument, muscles, and pericranium, anastomosing 

 with the supraorbital artery, and with the artery of the opposite side. 



The Dorsal Nasal Artery (a. dorsalis nasi; nasal artery), the other terminal branch 

 of the ophthalmic, emerges from the orbit above the medial palpebral ligament, 

 and, after giving a twig to the upper part of the lacrimal sac, divides into two 

 branches, one of which crosses the root of the nose, and anastomoses with the 

 angular artery, the other runs along the dorsum of the nose, supplies its outer 

 surface; and anastomoses with the artery of the opposite side, and with the lateral 

 nasal branch of the external maxillary. 



The Central Artery of the Retina (a. centralis retina) is the first and one of the 

 smallest branches of the ophthalmic artery. It runs for a short distance within 

 the dural sheath of the optic nerve, but about 1.25 cm. behind the eyeball it pierces 

 the nerve obliquely, and runs forward in the center of its substance to the retina. 



I Its mode of distribution will be described with the anatomy of the eye. 

 The Ciliary Arteries (aa. ciliares) are divisible into three groups, the long and short, 

 posterior, and the anterior. The short posterior ciliary arteries from six to twelve 

 in number, arise from the ophthalmic, or its branches; they pass forward around the 

 optic nerve to the posterior part of the eyeball, pierce the sclera around the entrance 

 of the nerve, and supply the choroid and ciliary processes. Trie long posterior 

 ciliary arteries, two in number, pierce the posterior part of the sclera at some little 

 distance from the optic nerve, and run forward, along either side of the eyeball, 

 between the sclera and choroid, tc the ciliary muscle, where they divide into two 

 branches; these form an arterial circle, the circulus arteriosus major, around the 

 circumference of the iris, from which numerous converging branches run, in the 

 substance of the iris, to its pupillary margin, where they form a second arterial 

 circle, the circulus arteriosus minor. The anterior ciliary arteries are derived from 

 the muscular branches ; they run to the front of the eyeball in company with the 

 tendons of the Recti, form a vascular zone beneath the conjunctiva, and then pierce 

 the sclera a short distance from the cornea and end in the circulus arteriosus major. 



The Muscular Branches, (rami musculares), two in number, superior and inferior, 

 frequently spring from a common trunk. The superior, often wanting, supplies 

 the Levator palpebrse superioris, Rectus superior, and Obliquus superior. The 

 inferior, more constantly present, passes forward between the optic nerve and Rectus 

 inferior, and is distributed to the Recti lateralis, medialis, and inferior, and the 

 Obliquus inferior. This vessel gives off most of the anterior ciliary arteries. Addi- 

 tional muscular branches are given off from the lacrimal and supraorbital arteries, 

 or from the trunk of the ophthalmic. 



8. The anterior cerebral artery (a. cerebri anterior) (Figs. 516, 517, 518) arises 

 from the internal carotid, at the medial extremity of the lateral cerebral fissure. 

 It passes forward and medialward across the anterior perforated substance, above 

 the optic nerve, to the commencement of the longitudinal fissure. Here it comes 

 into close relationship \vith the opposite artery, to which it is connected by a short 

 trunk, the anterior communicating artery. From this point the two vessels' run side 

 by side in the longitudinal fissure, curve around the genu of the corpus callosum, 

 and turning backward continue along the upper surface of the corpus callosum 

 to its posterior part, where they end by anastomosing with the posterior cerebral 

 arteries. 



Branches. In its course the anterior cerebral artery gives off the following 

 branches : 



Antero-medial Ganglionic. Anterior. Posterior. 



Inferior. Middle. 



The Antero-medial Ganglionic Branches are a group of small arteries which arise 

 at the commencement of the anterior cerebral artery; they pierce the anterior 



