383 ARTERIES. 



the lower border of the Superior oblique muscle, passes to the inner angle of the 

 eye, where it divides into two terminal branches, the frontal and nasal. 



Branches. The branches of this vessel may be divided into an orbital group, 

 which are distributed to the orbit and surrounding parts ; and an ocular group, 

 which supply the muscles and globe of the eye. 



Orbital Group. Ocular Group. 



Lachrymal. Muscular. 



Supra-orbital. Anterior ciliary. 



Posterior ethmoidal. Short ciliary. 



Anterior ethmoidal. Long ciliary. 



Palpebral. Arteria centralis retinae. 

 Frontal. 

 Nasal. 



The lachrymal is the first, and one of the largest branches, derived from the 

 ophthalmic, arising close to the optic foramen, and not unfre,quently from that 

 vessel before entering the orbit. It accompanies the lachrymal nerve along the 

 upper border of the External rectus muscle, and is distributed to the lachrymal 

 gland. Its terminal branches, escaping from the gland, are distributed to the 

 upper eyelid and conjunctiva, anastomosing with the palpebral arteries. The 

 lachrymal artery gives off one or two malar branches, one of which passes 

 through a foramen in the malar bone to reach the temporal fossa, and anastomoses 

 with the deep temporal arteries; the other appears on the cheek, and anasto- 

 moses with the transverse facial. A branch is also sent backwards, through the 

 sphenoidal fissure, to the dura mater, which anastomoses with a branch of the 

 middle meningeal artery. 



Peculiarities. The lachrymal artery is sometimes derived from one of the anterior branches 

 of the middle meningeal artery. 



The supra-orbital artery, the largest branch of the ophthalmic, arises from that 

 vessel above the optic nerve. Ascending so as to rise above all the muscles of 

 the orbit, it passes forwards, with the frontal nerve, between the periosteum and 

 Levator palpebr* ; and, passing through the supra-orbital foramen, divides into a 

 superficial and deep branch, which supply the muscles and integument of the 

 forehead and pericranium, anastomosing with the temporal, angular branch of the 

 facial, and the artery of the opposite side. This artery in the orbit supplies the 

 Superior rectus and the Levator palpebras, sends a branch inwards, across the 

 pulley of the Superior oblique muscle, to supply the parts at the inner canthus, 

 and at the supra-orbital foramen frequently transmits a branch to the diploe. 



The ethmoidal branches are two in number, posterior and anterior. The 

 former, which is the smaller, passes through the posterior ethmoidal foramen, 

 supplies the posterior ethmoidal cells, and, entering the cranium, gives off a 

 meningeal branch, which supplies the adjacent dura mater, and nasal branches, 

 which descend into the nose through apertures in the cribriform plate, anasto- 

 mosing with branches of the spheno-palatine. The anterior ethmoidal artery 

 accompanies the nasal nerve through the anterior ethmoidal foramen, supplies the 

 anterior ethmoidal cells, and frontal sinuses, and, entering the cranium, divides 

 into a meningeal branch, which supplies the adjacent dura mater, and a nasal 

 branch which descends into the nose, through an aperture in the cribriform 

 plate. 



The palpebral arteries, two in number, superior and inferior, arise from the 

 ophthalmic, opposite the pulley of the Superior oblique muscle ; they encircle the 

 eyelids near their free margin, forming a superior and an inferior arch, which lie 

 between the Orbicularis muscle and tarsal cartilages; the superior palpebral 

 inosculating at the outer angle of the orbit with the orbital branch of the 

 temporal artery; the inferior pnlpebral anastomosing with the orbital branch of the 

 infra-orbital artery, at the inner side of the lid. From this anastomosis, a branch 



