|Henry Gray (18251861). Anatomy of the Human Body. 1918.|
|spaces of the angle of the iris (spaces of Fontana); they communicate with the sinus venosus scleræ and with the anterior chamber at the filtration angle. Some of the fibers of this trabecular tissue are continued into the substance of the iris, forming the pectinate ligament of the iris; while others are connected with the forepart of the sclera and choroid.|
| The endothelium of the anterior chamber (endothelium cameræ anterioris; posterior layer; corneal endothelium) covers the posterior surface of the elastic lamina, is reflected on to the front of the iris, and also lines the spaces of the angle of the iris; it consists of a single stratum of polygonal, flattened, nucleated cells.|
Vessels and Nerves.The cornea is a non-vascular structure; the capillary vessels ending in loops at its circumference are derived from the anterior ciliary arteries. Lymphatic vessels have not yet been demonstrated in it, but are represented by the channels in which the bundles of nerves run; these channels are lined by an endothelium. The nerves are numerous and are derived from the ciliary nerves. Around the periphery of the cornea they form an annular plexus, from which fibers enter the substantia propria. They lose their medullary sheaths and ramify throughout its substance in a delicate net-work, and their terminal filaments form a firm and closer plexus on the surface of the cornea proper, beneath the epithelium. This is termed the subepithelial plexus, and from it fibrils are given off which ramify between the epithelial cells, forming an intraepithelial plexus.
The Vascular Tunic (tunica vasculosa oculi) (Figs. 872, 873, 874).The vascular tunic of the eye is formed from behind forward by the choroid, the ciliary body, and the iris.
| The choroid invests the posterior five-sixths of the bulb, and extends as far forward as the ora serrata of the retina. The ciliary body connects the choroid to the circumference of the iris. The iris is a circular diaphragm behind the cornea, and presents near its center a rounded aperture, the pupil.|
FIG. 872 The choroid and iris. (Enlarged.) (See enlarged image)
FIG. 873 The arteries of the choroid and iris. The greater part of the sclera has been removed. (Enlarged.) (See enlarged image)
The Choroid (chorioidea).The choroid is a thin, highly vascular membrane, of a dark brown or chocolate color, investing the posterior five-sixths of the globe;