THE REGION OF THE ORBIT. 37 



the eyeball, and superior and external recti muscles ; 

 anteriorly it is closely adherent to the posterior aspect of 

 the upper lid. Within it are the lachrymal branch of 

 the ophthalmic artery, inosculating with the orbital 

 branch of the internal maxillary, with their accompany- 

 ing veins ; the lachrymal branch of the ophthalmic divi- 

 sion of the fifth nerve, which inosculates with the orbital 

 branch of the superior maxillary division of the fifth. 

 These structures enter at its posterior and external mar- 

 gin. The ducts of the lachrymal gland, which are about 

 ten in number, are so arranged that they open in a row 

 on to the conjunctiva, where it is reflected from the upper 

 lid to the globe. 



The lachrymal canals commence at the puncta lachry- 

 malia, which are seen, on everting the lid, as the centres 

 of small eminences, situated about a quarter of an inch 

 from the inner angle, on the inner aspect of the margin 

 of the lid. These minute openings are kept in contact 

 with the conjunctival surface of the globe by the action 

 of the tensor tarsi, so that they always lie in the current 

 of the tears. In each canaliculus, immediately below 

 the punctum, is a small cul-de-sac, beyond which, after 

 inclosing the caruncula, the canals join previous to en- 

 tering the lachrymal sac. Their posterior portion is 

 subconjunctival, a circumstance of considerable practical 

 value in the operation of reinstating the course of the 

 tears when from any cause the orifices of the puncta do 

 not perform their function of receiving the tears. That 

 portion which is common to both canaliculi is bound 

 down by the tendo-oculi. The process by which the 

 continuous flow of tears between the lachrymal gland 

 and the nose is kept up, is not entirely clear ; it is very 



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