The eye and its diseases / by D.B. St. John Roosa and Edward T. Ely.

  • Roosa, D. B. St. John (Daniel Bennett St. John), 1838-1908.
Date:
[between 1800 and 1899]
Catalogue details

Licence: Public Domain Mark

Credit: The eye and its diseases / by D.B. St. John Roosa and Edward T. Ely. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

    5/90
    THE ANATOMY AND PHYSIOLOGY OF THE EYE. That which we are accustomed to call the eye is a complicated structure of many different parts, not all of which are directly con- cerned in the act of vision. The whole may be properly termed the visual apparatus, and it may be conveniently described under four heads : (1) The Orbits ; (2) The Eyeball, or Globe of the eye, —the eye proper; (3) The Optic Nerves; (4) The Appendages of the Eye. The Orbits. The Orbits are the bony cavities in the front of the skull, in which the eyeballs are contain- ed. (See Fig. 43.) They are shaped like four-sided pyra- mids. The small ends of these pyramidal cavities are directed backward and are each pierced by an opening called the optic foramen (Latin, foramen, an opening), through which run nerves and blood-vessels. The large ends of the orbits open upon the face, and these facial openings have a strong, bony edge which protects the eye- ball from blows, etc. The or- bits are lined by a layer of fatty material, which forms elastic cushions for the eye- balls to rest upon, and thus gives them still further protec- tion against injury. Figure 43.—Skull, showing the orbits or bony cavities which contain the eyes. At the bottom of the right orbit is seen the optio foramen.