The American encyclopedia and dictionary of ophthalmology Edited by Casey AWood, assisted by a large staff of collaborators . nces straight, in others (luite oblique. Thosethrough which pass the long posterior ciliary arteries, the ciliary 374 ANATOMY (GROSS) OF THE HUMAN EYE nerves, and the vortex veins, course very obliquely; the canals forthe latter are about 3 mm. in length. The venae vorticosse, usuallyfour in number, are arranged in pairs, upper and lower; they leavethe sclera 6 to 8 mm. behind the equator, and their points of emer-gence are about 90 degrees apart. Loose connective tissu
The American encyclopedia and dictionary of ophthalmology Edited by Casey AWood, assisted by a large staff of collaborators . nces straight, in others (luite oblique. Thosethrough which pass the long posterior ciliary arteries, the ciliary 374 ANATOMY (GROSS) OF THE HUMAN EYE nerves, and the vortex veins, course very obliquely; the canals forthe latter are about 3 mm. in length. The venae vorticosse, usuallyfour in number, are arranged in pairs, upper and lower; they leavethe sclera 6 to 8 mm. behind the equator, and their points of emer-gence are about 90 degrees apart. Loose connective tissue binds thevessels and nerves to the walls of the canals. The oblique directionof these canals prevents bending and tearing of the structures pass-ing through them, during motions of the eyeball, or in the shiftingof the choroid during the act of accommodation. The scleral layer next the choroid is called the lamina fusca. Itis a dirty-brown layer, and is probably an extension into the scleraltissue of the choroidal pigment. It shows through the sclera as abluish discoloration, when that coat is abnormally thin, in some. Showing the Fibres of the Sclera Joining Obliquely Those of the Cornea andForming the Limbus Corneas. young children, in brunettes, and in most dark races. The scleraitself but rarely contains any pigment, except for the slate-grayspots often seen about the perforations for the anterior ciliary ves-sels (congenital melanosis of the sclera). Sattler and others believe that the human lamina fusca is analogousto the tapetum, a peculiar layer of the choroid found in lower is composed chiefly of connective tissue in. the pachyderms andruminants, and is known as the tapetum fibrosum. Irregular patchydeposits of pigment in these layers cause rays falling upon the retinaof such animals to be irregularly reflected, and produce a sheen suchas one sees on the surface of mother-of-pearl. This retinal reflexis also seen in the eyes of children. The inner surface
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectophthalmology, bookye
