Histologic changes in the ageing spiral tract.
To investigate the influence of ageing on the morphology of the bottom of the internal auditory meatus, we analysed 150 undecalcified pyramids of  human temporal bones. In most of the histologic sections examined, we found pointed bony spicules in the region of the spiral tract. These develop from layers of active and resting osteoid, reach their final morphologic shape in the fourth decade of life and then protrude into the internal auditory meatus, compressing the cochlear nerve fibers.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D002113:Calcification, Physiologic; D002648:Child; D002675:Child, Preschool; D003051:Cochlea / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010012:Osteogenesis; D013701:Temporal Bone / Q000033:anatomy & histology*