276 



PHYSIOLOGY 



CHAP. 



from the nasal branch of the ramus ophthalmicus of the 

 trigeminus, a motor root from the oculo-motor, and afferent and 



Fi<;. 114. A, arteries of the choroid and iris, lateral view ; B, veins of the choroid, lateral view. 

 (From Arnold.) a, optic nerve ; b, part of sclerotic left behind ; c, region of ciliary muscle ; 

 d, iris ; 1, posterior ciliary arteries piercing sclerotic and passing along choroid ; 2, one of the 

 long ciliary arteries ; 3, anterior ciliary arteries ; 1, 1, two trunks of the venae vorticosae at 

 the place where they leave the choroid and pierce the sclera. 



efferent roots from the plexus cavernosus of the sympathetic. 



The long and short ciliary nerves are given off from the ganglion 



and sympathetic plexus, 

 and penetrate by the pos- 

 terior part of the sclera in 

 12-20 little bundles to the 

 eye, run across its posterior 

 surface, and are ultimately 

 distributed to the ciliary 

 body, iris, and cornea (Fig. 

 116). 



II. From the physio- 

 logical standpoint two 

 parts must be distinguished 



FK, H5.-Nerve S of the orbit, ,atera, view. Reduced ,. the Structure of the eye- 



(Sappey.) The ramus externus is divided and turned ball : the retinal portion 01 



back. 1, optic nerve ; 2, trunk of third nerve ; 3, its ji n 



superior division to the levator palpebrae and rectus the inner COat, Containing 



superior 

 inferior oblique 



4, its lower and longer branch to the fV>p pvnfmrlprl rprmi rmHrm 

 liue 5 sixth nerve oined b branches tne ex P ana( 



, 



of the sympathetic; 6, Gasserian ganglion; 7, of the Optic nerve, On which 

 ophthalmic nerve; 8, its nasal branch; 9, ciliary , r> v 



ganglion ; 10, its short, 11, long, 12, and sympathetic the SpeClUC lUnCtlOn OI the 



nerve! 13 ' ** OTb M> supra - rbital eye as the peripheral organ 



of vision depends, and the 



other parts of the eye, which constitute a complicated dioptric 

 system. 



This physiological distinction is sanctioned by the embryo- 

 logical development of the eye (for which see Text -books of 



