. A treatise on diseases of the eye . and vein. The anterior foramen, situated 17 nun. back of theupper extremity of the crista lachrymalis, gives passage to the anteriorethmoid artery and nasal nerve. Eyeball and Contents of Orbit.—The eyeball is a globular uiasswhich is lodged in the orbit, suj)j)()rted on a cushion of fat, and heldin position by connective-tissue aponeuroses, ocular nuiscles, and theeyelids. 32 ANATOMY Normally the eyeball protrudes beyond the margin of the orbit. Atthe nasal side the projection is approximately 5 mm.; at the temporalside, 11 to 12 mm. The globe is covered
. A treatise on diseases of the eye . and vein. The anterior foramen, situated 17 nun. back of theupper extremity of the crista lachrymalis, gives passage to the anteriorethmoid artery and nasal nerve. Eyeball and Contents of Orbit.—The eyeball is a globular uiasswhich is lodged in the orbit, suj)j)()rted on a cushion of fat, and heldin position by connective-tissue aponeuroses, ocular nuiscles, and theeyelids. 32 ANATOMY Normally the eyeball protrudes beyond the margin of the orbit. Atthe nasal side the projection is approximately 5 mm.; at the temporalside, 11 to 12 mm. The globe is covered by the eyelids. The mass offat contained in the orbit is lobulated; it serves to fill all the space inthe orbit not occupied by the eyeball and the structures to be extent anteriorly is limited by the septum orbitale; normally theorbital fat does not pass beyond the membranous aponeurosis whichsprings from the portion of Tenons capsule at the equator of the globe,where Tenons capsule is adherent to the recti Jim Position of eyeball in the orbit: Rl, external rectus; /?s, superior rectus; Lp, levator palpebrae;Os, Tr, superior oblique, with its pulley; Rm, internal rectus; Oi, inferior oblique; Pi, inferiorrectus. (Merkel.) The eyel)all may be said to be formed of segments of two globes,one having a radius of curvature of 12 mm. (sclera), the other a radiusof curvature of mm. (cornea). The membranes of the eyeball arethree in number: (1) Fibrous (outer); (2) vascular (middle); (3) nervous(inner). The fibrous membrane consists of two parts-—the cornea, situ-ated in the anterior portion of the globe, comj)rising about one-seventhof the area; the sclera, comprising the remaining portion of this mem-brane. The fibrous membrane is a stiff, highly resisting membrane;it serves to maintain the shape of the eye and to withstand the intra-ocular tension. The middle tunic of the eyeball extends from the optic nerve entranceto within about 1 mm. of the sclero
Size: 1454px × 1719px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjecteyediseases, bookyear
