508 



THE BLOOD-VASCULAR SYSTEM. 



anterior ethmoidal cells and frontal sinuses, and, entering the cranium, gives off 

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

 which descend into the nose, through the slit by the side of the crista galli, and, 

 running along the groove on the under surface of the nasal bone, supply the skin 

 of the nose. 



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

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

 orbit to encircle the eyelids near their free margin, forming a superior and an 

 inferior arch, which lie between the Orbicularis muscle and tarsal plates ; the 

 superior palpebral inosculating at the outer angle of the orbit with the orbital 

 branch of the temporal artery, and with the upper of the two external palpebral 

 branches from the lachrymal artery the inferior palpebral inosculating, at the 

 outer angle of the orbit, with the lower of the two external palpebral branches 

 from the lachrymal and with the transverse facial arteries, and at the inner side 

 of the lid with a branch from the angular artery. From this last anastomosis a 

 branch passes to the nasal duct, ramifying in its mucous membrane, as far as the 

 inferior meatus. 



Fissure of 

 Rolando 



FIG. 292. Vascular area of the upper surface of the cerebrum. (After Duret.) I. The part supplied by the 

 external and inferior frontal artery. II. The part supplied by the ascending frontal. III. The part supplied 

 by the ascending parietal. IV. The part supplied by the parieto-sphenoidal artery. 



The frontal artery, one of the terminal branches of the ophthalmic, passes from 

 the orbit at its inner angle, and, ascending on the forehead, supplies the integument, 

 muscles, and pericranium, anastomosing with the supraorbital artery and with the 

 artery of the opposite side. 



The nasal artery, the other terminal branch of the ophthalmic, emerges from 

 the orbit above the tendo oculi, and, after giving a branch to the upper part of 

 the lachrymal sac, divides into two branches, one of which crosses the roct of 

 the nose, the transverse nasal, and anastomoses with the angular artery ; the 



