236 Prof. A. Macalister. Notes on the Varieties and 



Of other points of superficial anatomy in connexion with this bone, 

 the following may be noticed. While, in general, the orbital sur- 

 face is uniform, I have several times found it to be irregular, pro- 

 bably as the result of accident. Usually this takes the form of 

 irregular surface depressions. It may also present vascular grooves 

 for branches of the infra-orbital artery, but these are not common. 



The inner surface below presents two lamellar processes : 



1. Processus lachrymalis, the very variable concave lamella which 

 projects into the nasal canal ; usually this ends below in a rounded 

 border, but in a few it ends in an acute down-directed point. The 

 length of this rarely exceeds 3 millims. ; the maximum which I have 

 found is 6 millims. 



2. The processus turbinalis, or the inferior internal margin, is by 

 far the most irregular portion of the bone ; it touches the inner side 

 of the maxilla in front of the opening of the antrum, and generally is 

 prolonged downwards to a point where it converges with the pro- 

 cessus lachrymalis. 



The lower margin of this articulates with the processus lachrymalis 

 of the maxillo-turbinal in about 66 per cent, of cases. The forms of 

 this articulation are variable ; but in 70 per cent, the outer surface of 

 the turbinal overlaps a small space of the inside of the process of the 

 lachrymal. 



The outline of this processus turbinalis is rudely triangular in 

 about 70 per cent, with three sharp margins ; in some there are four 

 edges, an additional one being placed between the lachrymal process 

 and the point of the turbinal process. 



V. In size and degree of development there is little difference between 

 the bones of the two sexes ; the average male lachrymal has a maxi- 

 mum length in the orbit of 16'5 millims. (not counting the downward 

 extension of the processus lachrymalis), the average female has a length 

 of 15'5 millims. The shortest normal adult bone measured 8 millims., 

 the longest 19'5. The breadth at the lowest border was more variable, 

 the average being 9'5, the extremes 4 and 14. The lachrymal index 



averaged 60, but many varied between 42 and 75, the average 







female index being a little higher than the male. The width of the 

 upper edge is the most variable, the widest of 70 measurements was 

 11 millims., the narrowest 2, the average 7'75. 



The hamulus is commoner in male than in female skulls. 



VI. The vascular relations of the lachrymal bone are usually very 

 definite, a branch of the infra-orbital passes under, through, or over 

 the hamulus into the lachrymal canal ; branches of the infra-orbital 

 and of the angular artery pierce the suture between the maxilla and 

 lachrymal anteriorly and a branch of the nasal division of the ophthal- 

 mic artery passes through the suture at the fronto -maxillary angle 



