Histopathological Study on the Pathologic Changes of the Conductive Structure of the Middle Ear of the Human Temporal Bones

Pathologic changes in the tympano-ossicular chain and mucous membrane of the middle ear cavity were histopathologically examined on the horizontal and frontal serial celloidin sections from the 110 human temporal bones in age ranging from new born to 82 years. The results were as follows:1) Inflammatory changes such as fibrous thickening and adhesion of mucous membrane with cell infiltration in the middle ear cavity were found in 95.5%. 2) The changes relating to otitis media were as follows; (a) Fibrous thickening more than 100μ (69%), focal calcification, retraction and fibrous adhesion, rupture and complete destruction (0.9%) of the tympanic membrane, (b) Slight resorption of the cortex of the ossicles, circumscribed resorption in the tip of the crus longum of the incus (41.7%) and complete destruction of the ossicles (0.9%), (c) Fibrous thickening including excessive proliferation of the mucous membrane of the middle ear cavity associated with irregular narrowing of the cavity (10.9%), 3) The changes relating to aging were as follows; (a) Regressive changes of the articular cartilage of the ossicles, (b) Progressive decrease in thickness of the annular ligament resulting in impaction of the foot plate of the stapes to the margin of the vestibular window in 11.8% over 30 years old. 4) Congenital ankylosis of the head of the malleus with the bony wall of the epitympanum occurred in 0.9%. 5) Infiltration of metastatic carcinoma (4.6%) and leukemic cells (11.8%) in the external ear canal, middle ear, and bone marrow, resulting in occasional destruction of the structure of the conductive system. 6) Development of the functional structure of the ossicular chain was considered dependent on mechanical stimulation in transmission of sound pressure.