750 



HUMAN ANATOMY. 



smaller and less constant of the two, passes through the posterior ethmoidal foramen and is 

 distributed to the mucous membrane lining the posterior ethmoidal cells and the upper poste- 

 rior part of the nasal septum, v\'here it anastomoses with the spheno-palatine branch of the 

 internal maxillary'. It sometimes arises from the supraorbital artery. The anterior ethmoidal 

 (a. ethmoidalis anterior) passes through the anterior ethmoidal foramen along with the nasal 

 nerve, and, entering the cranium, passes forward over the cribriform plate of the ethmoid to the 

 nasal slit at the side of the crista galli. Through this slit it enters the nasal cavity and passes 

 downward in a groove upon the under surface of the nasal bone, supplying the nasal mucous 

 membrane. While within the cranium it gives off a small meningeal branch to the dura mater 

 of the anterior portion of the cranium, and it also sends branches to the mucous membrane 

 lining the anterior and middle ethmoidal cells and the frontal sinuses. 



C ^) The palpebral branches (aa. palpebrales mediales) are two in number, and are distrib- 

 uted to the upper and lower eyelids respectively. They arise opposite the pulley of the superior 

 oblique muscle and descend towards the inner canthus of the eye. Each artery then bends out- 

 ward towards the outer canthus along the free border of the lid, between the tarsal cartilage 

 and the orbicularis muscle, forming the palpebral arches {arcus tarseus superior et inferior). 



Fig. 697. 



Lacrimal artery 

 Anterior ethmoidal 



Posterior ethmoida 

 Ophthalmic artery 

 Optip nerve \ 



Internal carotid artery 

 Posterior clinoid 

 process 



Int. carotid artery, 

 cavernous portion 



Supraorbital 

 artery 



Frontal artery 



Nasal artery 

 Superior and in- 

 ferior palpebral 

 arteries 

 Angular artery 



.Anterior ciliary 

 arteries 



Infraorbital 

 artery 



Facial artery 



/ / 7 .^21 it^M^ ^/ It ' 



Arteria centralis retinae' 

 Long posterior ciliary artery 

 Short posterior ciliary arteries 



Internal maxillary artery ' ■; 



Branches of ophthalmic artery, seen from side after removal of lateral orbital wall. 



from which branches pass upward or downward, as the case may be, to supply the orbicularis, 

 the Meibomian glands, and the integument of the lid. As they approach the outer canthus, the 

 arches anastomose with the palpebral branches of the lachrymal artery. 



{h) The frontal branch (a. frontalis) is usually small, and is distributed to the integument 

 over the glabella and to the pyramidalis nasi and frontalis muscles. It also sends some twigs 

 to the eyelids. 



(?) The nasal artery (a. dorsalis nasi) is the true terminal branch of the ophthalmic. It 

 passes downward in the angle formed by the nose and the lower eyelid and becomes directly 

 continuous with the angular portion of the facial artery. In its course it gives branches to the 

 walls of the lachrymal sac and to the integument of the root of the nose. 



Anastomoses. — The principal communications of the ophthahnic artery are 

 with the superficial temporal, internal maxillary, and facial branches of the external 

 carotid. With the first of these it communicates extensively by means of the supra- 

 orbital branch and less importantly throu.^h the anastomosis of the malar branch of 

 the lachrymal with the transverse facial artery. It makes a very important anasto- 



