A text-book on diseases of the eye / by Henry D. Noyes.

  • Noyes, Henry D. (Henry Drury), 1832?-1900
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: A text-book on diseases of the eye / by Henry D. Noyes. Source: Wellcome Collection.

    24/780 page 6
    blood-vessels ag-gregated together in the choroid and the ciliary processes is required to secrete the pigment and to furnish nutritive material for the vitreous body and lens, which have no blood-ves- sels. Outside of the ciliary body, inserted between it and the sclera, is a mass of muscular fibres, known as the ciliary muscle (see Fig. 2). Its most exterior fibres run in the meridians of the eye; those which lie next, run in oblique directions which slant more and more as we go deeper, until we come to the innermost set, which take a circular direction. The whole mass, in meridional section, has a tri- angular form, whose apex and point of attachment is near the canal of Schlemra. The place of attachment is called 'by Gerlach the ligamentum annulare. The anatomy of this region of the eye was long misun- derstood, and there is likely to be confusion from the variety of terms which have been employed at different periods. The inser- tion of the ciliary muscle is upon the choroid, and its effect is to relax the fibres which pass from the tips of the ciliar^^ processes to the margin of the lens, and Avhich fibres are known as the zonula of Zinn, or, suspensory ligament of the lens. This name is also ex- tended to a transparent membrane which lies between the ciliary body and the vitreous. Tlie purpose and effect of the ciliary muscle is to permit the crystalline lens to become more convex. The space between the ciliary processes and the margin of the lens has im- portance in reference to the escape of fluid from the vitreous to the canal of Schlemm and the exterior circulation of the eye. The iris has pigment, blood-vessels, epithelium, and also muscular fibres which regulate the size of the pupil; iris, ciliary body, and choroid, are together known as the uvea. VESSELS OF THE GLOBE AND THEIR RELATIONS TO THE DIAGNOSIS OF DISEASES OF THE EYE. As preliminary to an understanding of how to diagnosticate its inflammations, it lies next m order to speak of the mode in which the eye and its appendages are supplied with blood. Our present knowledge is largely derived from the skilful injections of Professor Leber, whose diagram is introduced below (Fig. 4). The vessels of the palpebral conjunctiva, and of the portion which passes from the lids to the globe, are derived from the vessels of the lids, viz., the median and lateral palpebral arteries and their accompanying veins. As we approach the cornea, the vessels of the conjunctiva unite with those from another source, viz., the ter- minal branches of the anterior ciliary arteries. At the optic nerve entrance a circlet of vessels anastomoses with the choroid.
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