THE FACE 377 



rymal process of the malar. The upper edge of this process is emar- 

 ginate and known as the lachrymal notch. The lachrymal groove 

 passes between the base of this process and the anterior-inferior angle 

 of the bone, and thus divides the lower border in front into two 

 parts. 



The internal or nasal surface of the lachrymal is flat and forms 

 part of the lateral wall of the nasal cavity, especially that region 

 opposite the ethmoidal cleft, which is the outer wall of the middle 

 nasal meatus. Its anterior border is bevelled and overlaps the max- 

 illary ; its anterior-inferior angle joins the maxillo-turbinal swelling 

 on the inner surface of the maxillary which contains the lachrymal 

 duct, and also joins the end of the ethmoidal cleft plate, the rudi- 

 mentary uncinate process. Above the angle a notch completes the 

 lachrymal opening. Close to the posterior border is attached the 

 posterior edge of the plate bounding the ethmoidal cleft of the lateral 

 ethmoid. 



Nomenclature. Lachrymal is from the Latin lachryma, a tear. 

 Os lacrimale, I'os lacrimal, and das Thranenbein all express the same 

 relation to the tear-duct. Os unguis and the French I'unguis are 

 from the Latin unguis, a finger-nail, owing to the thin, scale-like 

 character of the bone. 



Determination. When the smooth concave surface is held upper- 

 most, the hamulus toward the student and the groove directed away 

 from the student, the groove is on the side to which the bone belongs. 



Articulation. The lachrymal articulates with the frontal, the 

 maxillary, the malar, the palatine, the ethmoid, and the maxillo- 

 turbinal. 



Muscular Attachments. To the lachrymal tubercle are attached 

 the orbicularis palpebrarum and the levator labii superioris. 



Ossification. The lachrymal is developed from one centre of 

 ossification. 



VARIATIONS IN THE LACHRYMAL BONES. 



The size of the lachrymal may be roughly measured by taking the 

 greatest antero-posterior diameter and the length of the anterior 

 border. These measurements vary as follows : 14, 10 ; 12.5, 8 ; 12, 

 10; 12, 9; 11, 10; 11, 1); 11, 8; 10.5, 8; 10, 9 ; 9.5, 10; 9.5, 9; 9, 

 9 ; 9, 8 ; 9, 7 ; 8, 10 ; 8, 8 ; 8, 7.5 ; 7, 8 ; 7, 7. Beyond differences in 

 size and shape, which are in part dependent upon the degree of de- 



