. Quain's elements of anatomy . sionally with each other before supplying the corneaand entering the ciliary muscle. When the sclerotic is careftilly separatedfrom the subjacent structiu-es, these nerves are seen lying on the surfaceof the choroid, into which they send branches, and in which they form agangliated plexus amongst the blood-vessels, the groups of ganglion-cellsbeing often applied to the walls of the vessels. Within the ciliary musclethe nerves also subdivide minutely, forming here another plexus, whichcontains a number of medullated fibres, and the cells of which aresmaller. A fe
. Quain's elements of anatomy . sionally with each other before supplying the corneaand entering the ciliary muscle. When the sclerotic is careftilly separatedfrom the subjacent structiu-es, these nerves are seen lying on the surfaceof the choroid, into which they send branches, and in which they form agangliated plexus amongst the blood-vessels, the groups of ganglion-cellsbeing often applied to the walls of the vessels. Within the ciliary musclethe nerves also subdivide minutely, forming here another plexus, whichcontains a number of medullated fibres, and the cells of which aresmaller. A few recurrent branches appear to pass back from it into thechoroid coat, but the greater number pass on to the iris (fig. 343, a, ct).In the iris the nerves follow the course of the blood-vessels, dividinginto branches, which communicate with one another as far as the pupil, 408 THE EYE. forming a close plexus of fine non-mecluUated fibres. Their ultimatedestination is probably the muscular tissue of the iris and of its Fi?. Fig. 343. — Distribution of NERVES IN THE IKIS (Kollikcr). 50 Diameters. Tlie preparation was from theeye of an albino rabbit; a, smallerbranches of the ciliary nervesadvancing from the choroid; b,loops of nnion between them atthe margin of the iris ; c, arches ofunion in the iris ; c, finer networkin the inner part; e, sphincterpupillffi muscle. THE EETIWA. The retina is a delicate membrane, which contains the expandedtermination of the optic nerve. It lies within the choroid coat, andrests on the hyoloid membrane of the vitreous humour. It extendsforwards nearly to the outer edge of the ciliary processes of the choroid,where it ends in an indented border, named ora serrata. From this borderthere is continued onwards a thin layer of a different structure andcontaining no nerve-fibres, the ;paTS dliaris retincB, which reaches as far Fig. 344. — The back of theretina with the point ofentrance of the optic nerveas seen with the ophthal-MOSCOPE (E. Jae
Size: 2081px × 1201px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
