LACRYMAL ORGANS. 



and another rather within the lower eyelid. 

 See/gs. 12 & 14. 



Jig. 14. 



deeply scooped out, and is about eight-tenths 

 of an inch long and five-twentieths broad. 



The outer aspect of the nasal process of the 

 superior maxillary bone is divided by an as- 

 cending ridge, the continuation of that forming 

 the lower margin of the orbit, into two sur- 

 faces. The posterior surface, which is the 

 narrower, forms the anterior half of the lacry- 

 mal groove. The posterior half of the groove 

 is formed by that narrow grooved part of the 

 orbital surface of the lacrymal bone in front of 

 its vertical crest. The line of junction (shin- 

 dylesis) between the posterior margin of the 

 nasal process of the superior maxillary bone 

 and the anterior margin of the lacrymal runs 

 down longitudinally in the bottom of the 



A left eye with the eyelids cut in the middle, and 

 the outer halves everted to show the orifices of the 

 ducts of the lacrymal gland, into which hairs are 

 inserted. 



The preceding description of the lacrymal 

 gland and its ducts shows that the latter and 

 the lower mass at least of the former may be 

 readily wounded along with the upper eyelid, 

 and that in Crampton's operation for entro- 

 pium, the lower mass of the gland, together 

 with some of the lacrymal ducts, must neces- 

 sarily be wounded, if the eyelid be cut through 

 near the outer angle and to any height. In 

 cases in which I have performed the operation, 

 however, I have not observed any lacrymal 

 fistula or other bad consequence follow. 



Tears. Lacrymte, Fr. Les larmes ; Ital. 

 Le lagrime; Germ. Die Thranen. The lacry- 

 mal secretion like the salivary appears con- 

 stantly to flow, though in no greater quantity 

 than is sufficient to moisten the surfaces of the 

 conjunctiva. The derivative lacrymal organs 

 are in this case equal to the removal of it; but 

 when the tears are poured out in unusual 

 quantity, as they are, like the salivary or uri- 

 nary secretion as well as that of the skin, in 

 certain affections of the mind, they run over 

 the margin of the lower eyelids and drop down 

 the cheeks. 



According to Fourcroy and Vauquelm there 

 remains after evaporating the tears, about one 

 per cent, solid substance, which consists chiefly 

 of common salt and a yellow extractive matter 

 perfectly soluble in water. Before drying, this 

 appears quite similar to mucus. 

 2. Derivative lacrymal organs. 

 Previously to describing the passages by 

 which the tears are drawn off into the nose, it 

 will be advantageous to take a glance at the 

 osseous groove and canal in which the prin- 

 cipal part of those passages is lodged. 



Osseous groove for the lodgement of the 

 lacrymal sac. The lacrymal groove, sulcus la- 

 crymalis, is situated at the fore part of the 

 inner wall of the orbit. It is directed from 

 above downwards, extending from the junc- 

 tion of the frontal bone with the nasal process 

 of the superior maxillary and with the lacrymal 

 bone, on the one hand, and to the inner and 

 lower angle of the margin of the orbit on the 

 other. Here it runs into the osseous canal for 

 the nasal duct. The lacrymal groove is pretty 



groove. 



J\JVC. 



The anterior margin of the lacrymal groove 

 formed by the ascending ridge subdividing the 

 outer surface of the nasal process of the supe- 

 rior maxillary bone, is thick and rounded. The 

 posterior margin, formed by the crest which 

 subdivides vertically the orbital surface of the 

 lacrymal bone, is thin and sharp. 



Inferiorly the crest of the lacrymal bone 

 forms a small curved prolongation directed for- 

 wards and outwards, which serves to form the 

 commencement of the posterior wall of the 

 osseous canal for the nasal duct. The process, 

 which is called hamulus ossis lacrymalis, arti- 

 culates with the orbital plate of the superior 

 maxillary.* 



The osseous canal for the nasal duct. The 

 osseous nasal canal, about half an inch in 

 length, extends from the lower extremity of the 

 lacrymal groove to the lowest meatus of the 

 nose, at the anterior part of which it opens. 

 Its orifice is overhung by the anterior extremity 

 of the lowest spongy bone. The osseous nasal 

 canal is directed a little obliquely from before 

 back wardst. and from within outwards. It is 

 somewhat narrower in the middle than at either 

 extremity. It is compressed from within out- 

 wards, hence a horizontal section is rather 

 elliptical than circular. 



The anterior and outer walls of the osseous 

 canal are formed by a groove inclined down- 

 wards and backwards on the inner surface of 

 the body of the superior maxillary bone, the 

 continuation of that on the nasal process which 

 contributes to form the lacrymal groove. The 

 posterior wall of the canal is in great part 

 formed above by the hamular process of the 

 lacrymal bone, where it articulates with the 

 orbital plate of the superior maxillary. The 

 lowest part of the posterior wall is formed by 

 the meeting together of the lacrymal process 



* In man the lacrymal bone does not alway^s 

 form a single piece. " In a great number of cass, 

 says M. Rousseau, " the lacrymal bone is found 

 divided into two unequal parts, even in aged sub- 

 jects The larger contributes to form the inner 

 wall of the orbit, the smaller is situated below 

 and outside the preceding on the floor of the orbit ; 

 its exposed surface does not measure more than 

 two millimetres in extent, but it dips under the 

 vertical crest of the first portion, and contributes 

 to form the lacrymal canal." See " Description 

 d'un nouvel os de la face chez I'homme, m An- 

 nales des Sciences Naturelles. Paris, 1829. 



