The changes of the tympanic membrane in serous otitis media are influenced by the conditions of its middle ear cavity.
The area of the tympanic membrane is classified pars tensa and pars flaccida, the former is rigid and the latter is flaccid. It is considered that these characters of the tympanic membrane are related to the development of chronic middle ear diseases.
In this study morphorogical changes of the pars tensa were observed with an ENT fiberscope, light microscope, and scanning electron microscope in experimental serous otitis media. The experimental serous otitis media models with intact tympanic membrane were made by three method in rabbit ; coagulation of the pharygeal orifice, obstruction of the tympanic orifice, injection of silicon into the bulla.
Under general anesthesia (Pentobarbital sodium 50 mg/ml) the mouth was opened the soft palate was cut and the pharyngeal orifice was coagulated in the first method.
The second method consisted of obstructing the tympanic orifice with autogenous muscle through the bulla under general anesthesia and local anesthesia (1% Xylocaine).
The third method used injection of silicon into the bulla. Of the 118 ears, 83 ears (70%) developed serous otitis media, 35 ears (30%) were purulent otitis media. Animals were killed at predetermined times from 1 week to 15 weeks after each treatment.
1. The changes of the tympanic membrane were observed with the ENT fiberscope: The pathologic changes of the tympanic membrane in experimental otitis media were retraction of the pars flaccida and tensa, dullness or plaque in pars tensa.
These findings are similar to the changes of the tympanic membrane in human serous otitis media.
2. Histopathological findings of the pars tensa in the light microscope: The animal bulla and external auditory meatus with experimental serous otitis media was removed and fixed in 10% neutral formalin. In addition to H-E, Masson stains, PTAH stains were also used.
The results were as follows: The epithelial layer of the pars tensa was hyperplastic, although in less degree than in pars flaccida. The subepithelial connective tissue was slightly edematous, where vascular congestion, inflammatory cell infiltration and proliferation of fibroblast are shown.
3. The fiber arrangement of pars tensa in experimental otitis media (serous, purulent) examined with SEM: The tympanic membrane and bulla with experimental otitis media (serous, purulent) were removed, fixed in 1% glutalaldehyde. Specimens were incubated in 0.1% Pronase E in phosphate buffer solution at 37°C for 10-12 hours and washed by distilled water. This procedure removed most of mucous layer of the tym-panic membrane leaving the intermediate fibrous layer. Specimens were dehydrated with a series of ascending concentration of alcohol, allowed dry, and coated with carbon and gold in a vacum evaporator. They were examined with SEM from the side of the middle cavity. The results were as follows: The bundles of fibers in pars tensa were arranged like cross-link in normal animals. On the dull portion of the pars tensa in experimental serous otitis media, the fibers were tangled and the cross-linked arrangement disappeared.
In experimental purulent otitis media, the fibers were denatured and looked like loops.
It is thought the destruction of the fiber bundle arrangement in experimental otitis media is the cause of loss in rigidity of the pars tensa, which may easily be retracted by negative pressure in the middle ear.
These conditions, which are characterized by hyperplastic epithelium layer and destruction of the fiber arrangement of the intermediated layer, are considered to be due to infection and negative pressure of middle ear cavity. It may be possible that such changes of the tympanic membrane, reccurent or continuous, induce chronic changes of the middle ear such as adhesive otitis media, tympanosclerosis and cholesteatoma.

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In order to study the growth of frontal sinus with age, the frontal sinus was measured using X-ray tomography in a total of 1, 942 Japanese, 4 to 59 years in age without paranasal sinusal diseass (984 males and 958 females). The deta obtained were treated statistically with the following results.
1) The frontal sinus was found to be present in 84% at the age of 10 years and 96% at 19 years in male and in 74% and 96%, respectively, in female. Thus, it appears that the frontal sinus is present in a high percentage of subjects even under 10 years of age and that at least until 19 years of age presence or absence of the frontal sinus is determined. When conparisons are made between the left side and the right side, the frontal sinus was detected with higher incidences in the left side for both sexes.
2) The width of the frontal sinus shows growthdegree much greater than that seen in the frontal bone from about 6 to 8 years of age for both sexes. The growth almost completes until 16 to 18 years for males and 12 to 14 years for females. For male cases four growth patterns were seen in both left and right sides. On the other hand, the growth in the left side showed four patterns, whereas no pattern was observed in the right side.
3) The growth in the height of the frontal sinus started and completed at about the same periods as observed for the growth in the width of frontal sinus. However, some differences were seen in growth with age. For males the growth in the right side proceeded at a constant rate, but in the left side three patterns were found. On the other hand, in the females there were three patterns in the right side and four patterns in the left side.
4) The global growth rate of frontal sinus (maximal width of frontal sinus maximal height of frontal sinus/maximal width of orbita ×100) was examined as one of the index for growth of the frontal sinus. It was found that growth-degree much greater than that observed for the frontal bone starts from about 6 to 8 years for both males and females. Four patterns were seen in growth in the left side for both males and females, while in the right side for females no pattern was noted in growth. The growth almost completed by 18 to 19 years for males and by 12 to 14 years for females.
5) Marginal morphology tended to be more complexed with age for both males and females. In addition, there was a tendency that the greater the frontal sinus is the more complexed became the marginal morphology.
6) For both sexes, high positive correlation was seen in the growth between the width and the height of the frontal sinus and also in the growth of the height of the frontal sinus between left and right. Thus, it is considered that the frontal sinus shows growth in both width and height harmoniously.
7) In the growth of frontal sinus difference was seen between the right side and the left side, with superiority in growth in the left side. It was postulated that this difference may be explained by the fact that the difference in aeration in the nasal cavity between the left and rigth sides originated from deviations of nasal septum is involved in pneumatization of the frontal sinus.

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What does ALGORITHM mean? The question is explained historically and by using two examples of the algorithms in otolaryngologic diagnosis and treatment. Then, the each program and the results are demonstrated.

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