THE GRADIENT OF THE POSTERIOR BONY WALL OF THE EXTERNAL AUDITORY MEATUS & ITS CLINICAL SIGNIFICANCE
- VernacularTitle:外耳道后骨壁倾斜角及其临床意义
- Author:
Guangyu LU
- Publication Type:Journal Article
- From:
Academic Journal of Second Military Medical University
1981;0(03):-
- CountryChina
- Language:Chinese
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Abstract:
In this investigation measurements of 5 items were taken on 100 skulls (200 temporal bones) kept in stock. The data obtained are as follows: (1) The sphenoidal angle is 117.6?. (2) The inclination of the long diameter of the isthmic part of meatus is 23.26?(3) The gradient of the posterior bony wall is 110.72?. (4) The visibility of the labyrinthine windows are classified into four types: in type 1, both windows are completely visible, 1.5%; in type II, partially invisible, 30.5%; in type III mostly invisible 61.5%; and in type IV, completely invisible, 6.5%. (5) The depth of the posterior tympanum: upper border of the oval window (external) is 3.37mm; lower border of the oval window (external) is 2.47mm and (internal) 2.38mm; upper border of the round window (external) is 2.07mm and (internal) is 3.07mm. From the above mentioned findings, the following conclusions could be drawn: The labyrinthine windows are not related to the inclination of the long diameter of meatus, but is closely related to the sphenoidal angle and the gradient of the posterior bony wall of the meatus, i. e. the greater the sphenoidal angle and the gradient of the posterior bony wall of the meatus, the poorer the visibility of the labyrinthine windows and the deeper the depth of the posterior tympanum except the depth of the lower border of the oval window. So it is considered that more attention should be paid to the gradient of the posterior bony wall when the posterior tympanotomy and transmeatal facial nerve decompression are being performed, and a large gradient is preferable.
