THE POSTERIOR CHAMBER 643 



the circulus minor. The entering arteries likewise form a circulus major 

 by anastomoses at the ciliary margin of the iris. 



The internal epithelium (posterior epithelium, pars iridica retinae) 

 resembles that of the ciliary body or pars ciliaris retinae, with which 

 it is continuous. The innermost (superficial) layer of epithelial cells, 

 in the iridal epithelium, is deeply pigmented and somewhat flatter than 

 in the ciliary body. The pigmentation is so deep that in the adult iris 

 it is scarcely possible to distinguish the two epithelial layers. These dan, 

 however, be readily seen in the fetal eye, and even in that of the child, 



THE ANTERIOR CHAMBER 



The anterior chamber is bounded in front by the posterior (internal) 

 surface of the cornea, and behind by the anterior surface of the crystal- 

 line lens and the anterior (external) aspect of the iris; it contains the 

 aqueous humor presumably largely a filtration product from the numer- 

 ous blood-vessels of this region, in part a secretion product of the ciliary 

 epithelium. Its anterior boundary is convex, its posterior concave, and 

 its circular margin is limited by an area which is known as the irido- 

 corneal angle. 



At this angle the mesenchymal epithelium is reflected from the poste- 

 rior surface of the cornea upon the anterior surface of the iris. The 

 latter portion of the epithelial layer is incomplete, since it presents nu- 

 merous openings which communicate with the lymphatic spaces between 

 the fibers of the ligamentum pectinatum and ciliary muscle. These lym- 

 phatic recesses are the spaces of Fontana. 



The ligamentum pectinatum consists of fibers which arise from 

 the margin of Descemet's membrane, and pass backward and inward, 

 in a radial direction, to the fibrous stroma of the iris and ciliary body. 

 Viewed from the cavity of the anterior chamber the fibers of this liga- 

 ment, with the intervening spaces of Fontana, present a toothed appear- 

 ance; the ligament derives its name from this peculiarity. 



THE POSTERIOR CHAMBER 



The posterior chamber is an annular cavity, somewhat triangular or 

 trapezoidal in transection, whose lumen, like that of the anterior cham- 

 ber, is occupied by aqueous humor, suspended in which are the fibers 

 of the suspensory ligament of the crystalline lens. 



