. Cunningham's Text-book of anatomy. Anatomy. Fig. 695.—Diagrammatic Reprksentation of the Radial Lines of the Foltal Lens. A, Seen from the front; B, From behind. respective!}" its anterior and posterior poles, a line joining which is known as its axis; its peripheral circumference is named the equator. Its axial measurement is 4 mm., and its transverse diameter from 9 to 10 mm. Its anterior surface is less curved than the posterior and on it rests the pupillary margin of the iris; the central part of the surface corresponds with the aper- ture of the pupil and is directed towards the an
. Cunningham's Text-book of anatomy. Anatomy. Fig. 695.—Diagrammatic Reprksentation of the Radial Lines of the Foltal Lens. A, Seen from the front; B, From behind. respective!}" its anterior and posterior poles, a line joining which is known as its axis; its peripheral circumference is named the equator. Its axial measurement is 4 mm., and its transverse diameter from 9 to 10 mm. Its anterior surface is less curved than the posterior and on it rests the pupillary margin of the iris; the central part of the surface corresponds with the aper- ture of the pupil and is directed towards the anterior chamber; the peripheral part is separated from the iris by tbe aqueous humour of the posterior chamber. Its pos- terior surface, more convex than the anterior, occupies the hyaloid fossa of the vitreous body. The curvatures of its surfaces, especi- ally that of the anterior, are constantly varying during life for the purpose of focussing near or distant objects on the retina. The substantia lentis consists of a soft outer part, the substantia corticalis, easily crushed between the finger and thumb, and of a dense central part, the nucleus lentis. The refractive index of the substantia corticalis is about 14; that of the nucleus lentis about 1-45. Faint radial lines run from the anterior and posterior poles of the lens towards its equator. In the foetus they are three in number, and form angles of 120° with each other (Fig. 696). From the anterior pole one ray ascends vertically and the other two diverge downwards, while from the posterior pole one ray descends vertically and the other two diverge upwards. In the adult the rays may be increased to six or more. They represent the free edges of a corresponding number of septa which dip into the substance of tbe lens, and along which the extremities of the different groups of lens fibres come into contact, and are attached by a clear, amorphous substance. The lens, when hardened, exhibits a series of concentrically arrang
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
