The Ophthalmic Artery is given off from the internal carotid in its fourth stage, beneath the anterior clinoid process: it may be exposed by the following dissection: —The brain should be removed from the cranium in the usual way; two vertical incisions should be next made, commencing, one at the external and the other at the internal angular process of the frontal bone: if these be directed so as to meet posteriorly in the sphenoidal fissure, they will be found to include between them almost the whole of the roof of the orbit, which may be then readily detached with the hammer. The other parts contained within the cavity of the orbit maybe exposed by the same dissection. Immediately after its origin the artery advances between the second or optic, and the third nerves, and enters the optic foramen, being lodged in a fibrous sheath formed for it by the dura mater. At first it lies on the outside of the optic nerve, then ascends to get on its superior surface, where it is covered by the levator palpebrae and superior rectus muscles, and accompanied by the nasal nerve: lastly, it runs horizontally forwards between the internal rectus and superior oblique muscles, towards the internal angular process of the frontal bone; here it terminates by dividing into the nasal and frontal arteries, both of which escape from the orbit in company with the infra-trochleator nerve, passing above the tendo oculi and beneath the pulley of the superior oblique muscle. The ophthalmic artery gives off the following branches:

Lachrymal.

Muscular.

Central artery of the Retina.

Ethmoidal.

Palpebral.

Supra-Orbital.

Frontal.

Ciliary.

Nasal.