EXAmNATION OF THE EYEBALL 



853 



there are no lymphatic vessels in the eyeball, but the fluid is contained in spaces of 

 various sizes. Tlicse are usually divided into an anterior and a posteri<jr set. 



1. Anteriorly, we have the anterior and posterior aqueous chambers, which 

 communicate freely through the pui)il. The aqueous humour is secreted in tlie 

 posterior of these chambers, from the vessels of the ciliary body and posterior 

 surface of the iris (see also page 849). The stream passes mainly forwards througli 

 the pu])il into the anterior aqueous chamber, whence it escapes slowly bv passing 

 througli tlie s})aces of Fontana into Schlemm's canal, and thence into the anterior 

 ciliary veins. Part of the lymph-stream passes from the posterior aqueous cham- 

 ber backwards into the canal of Petit, out of which fluid can pass into the lens 

 substance, or diffuse itself into the front of the vitreous. 



In the cornea the lymph travels in the spaces already mentioned as existing 

 between the fibre-bundles, and in the nerve-channels, and at the periphery of the 

 cornea it flows off into the lym})]iatic vessels of the conjunctiva. 



Fig. 480. — Thk Lymphatics of thi-: Eyeball. (Diagrammatic. After Fuchs.) 



Anterior cilhtri/ rein 



CANAL OF SCHLEMM 



PROLONGATION OF TENON'S 

 CAPSULE ON TENDONS 



PERICHOROIDAL SPACE 

 HYALOID CANAL 



SPACE ROUND VENA VORTICOSA 

 COMMUNICATING WITH THE 

 PERICHOROIDAL SPACE AND 

 TENON'S SPACE 



TENONS SPACE 



SUPRAVAGINAL SPACE 



INTERVAGINAL SPACE 



In the iris there is a system of lymphatic spaces opening anteriorly on its 

 free surface by the crypts previously described, and communicating peripherally 

 Avith the spaces of Fontana. 



2. Posteriorly, we have (a) the central or hyaloid canal, lietween the ]tostt*- 

 rior pole of the lens and the optic nerve entrance, and {b) the perivascular canals 

 of the retina; the lymph from both of these situations flows into the spaces of the 

 optic nerve, which communicate with the intervaginal space of the nerve, and thus 

 with the great intracranial spaces. Further, between choroid and sclerotic, we 

 have (c) tlie ])erich()roidal si)ace, which gets the lym]>h from the choroid, and 

 communicates with Tenon's space outside the sclerotic by the jierforations corre- 

 sjionding to the vasa vorticosa and posterior ciliary arteries, and with the interva- 

 ginal space around the optic ncn-e entrance. Tenon's space, again, is continuous 

 with the supravaginal space around the optic nerve, which communicates l)oth 

 with the intervaginal spaces, with the lym])h spaces of the orbit, and directly with 

 the intracranial spaces at the apex of the orltit. 



