Notes on the varieties and morphology of the human lachrymal bone and its accessory ossicles

Abstract

Having examined 1000 lachrymal bones and the soft parts of the lachrymal region of over 300 orbits, I have compiled therefrom the following notes on the anatomy of these parts. The lachrymal is one of the most variable bones in the human skull, and one of the most perishable, being frequently destroyed by careless or ignorant methods of handling crania. I. I have notes of two instances of deficiency of the lachrymal bone. In one of these cases the whole wall of the groove is formed by the nasal process of the maxilla in front, and by the ethmoid and frontal behind; a small lacnna closed by membrane completing the boundary. In the second instance the right groove is entirely formed by the maxilla, the nasal process of which is expanded backwards (fig. 20, x ) into a flat plate behind the crista lachrymalis posterior ( y ), which also is maxillary. This plate articulates above with the frontal, and posteriorly with the prolonged orbital plate of the maxilla, which meets the frontal in a suture between the back of the nasal lamella and the front of the os planum. On the left side the lobe of the nasal process articulates by suture with the ethmoid, and below it there is a small lacuna (fig. 28, lac .), which may possibly have been filled by an ossicle. In this skull all the sutures are distinct, so the variety is not due to synostosis.