Histology of the Enchondral Layer of the Human Otic Capsule: Areas of Devitalized and Necrotic Bone

Abstract

The authors studied 50 otic capsules and 18 ossicles from human ears, concentrating their attention upon the degree of vitality of the enchondral layer in this area of the petromastoid portion of the temporal bone. Various histological techniques were employed, especially staining with Sudan Black or Sudan IV after decalcifying with 5% trichloracetic acid. The results obtained are compared with those obtained in the study of otic capsules of certain animals and in that of human diaphysial bones obtained from surgical amputations for malignant tumours or for gangrene due to atherosclerotic thrombosis. All the normal capsules studied showed, in the enchondral layer, extensive areas of fatty degeneration and of empty osteoplasts. The authors consider that these devitalized parts are areas of bone necrobiosis or of necrosis occurring in a bone tissue (the enchondral layer) which receives an insufficient nutrition because of the obliteration of a large number of its arteries.