Alterations in optic canal following resection of nerve in rats

The authors have studied relations between bony optic canal and nerve elements resulting from lesion in the optic nerve. Experimental animals were divided in two groups: young adults and old adult rats; the non-operated sides of rat skulls were used as a control group. At the same time in control samples the changes in osseous openings resulting from ageing were studied. Four months after surgery the animals were sacrificed, their skulls macerated and morphometric measurements taken by photometric and planimetric techniques. The obtained results show no significant difference in size of bony openings between the operated and non-operated sides. A significant difference has been found in the size of optic canal between the young and the old rats, regardless of the operated side. The authors have thus come to the conclusion that the size of bony canals in adult animals depends on their age in the first place. Narrowing of bony canaliculi, observed in the course of ageing, is most probably caused by primary osseous apposition, while atrophy of nerve elements may be considered as a secondary event.