Three-Dimensional Reconstruction and Measurement Study of Human Eustachian Tube Structures: A Hypothesis of Eustachian Tube Function

Histologic sections from nine temporal bones with eustachian tubes (ETs) attached were analyzed with a computer-aided three-dimensional reconstruction method to determine the curvature and tilt of the ET and the anatomic relationships between the medial lamina of the ET cartilage, the levator veli palatini muscle (LVPM), and Rosenmüller's fossa. It was found that the ET is convex superomedially and is tilted medially. The LVPM is located inferolateral to the inferior margin of the medial lamina of the anterior ET cartilage. The LVPM is inferior to the medial lamina of the posterior ET cartilage. These findings suggest that the LVPM opens the anterior cartilaginous portion of the ET by rotating the medial lamina with increased dimension of the muscle body when it contracts. Rosenmüller's fossa extends along the ET with rich lymphoid tissues as far as approximately one half the total length of the ET and very close to the skull base.

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Narrowest (ISTHMUS) Portion of Eustachian Tube: A Computer-Aided Three-Dimensional Reconstruction and Measurement Study

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348949710600710 ◽

1997 ◽

Vol 106 (7) ◽

pp. 583-588 ◽

Cited By ~ 42

Author(s):

Masaharu Sudo ◽

Isamu Sando ◽

Akihiro Ikui ◽

Chiaki Suzuki

Keyword(s):

Eustachian Tube ◽

Middle Ear ◽

Three Dimensional ◽

Three Dimensional Reconstruction ◽

Cross Sectional ◽

Computer Aided ◽

Dimensional Reconstruction ◽

Tensor Veli Palatini Muscle ◽

Normal Human ◽

Temporal Bones

Nine normal human temporal bones from persons 16 to 88 years old were studied by computer aided three-dimensional reconstruction and measurement. The length of the eustachian tube (ET) lumen in three portions (from pharyngeal orifice to tympanic orifice: cartilaginous, junctional, and bony) averaged 23.6 ±4.3 mm, 3.0 ± 1.9 mm, and 6.4 ± 2.6 mm. The narrowest portion of the ET lumen was in the cartilaginous portion in all cases: 20.5 ± 4.2 mm from the pharyngeal orifice and 3.1 ± 1.6 mm from the pharyngeal margin of the junctional portion. The cross-sectional area of the narrowest portion was 0.65 ± 0.2 mm2. The tendon of the tensor veli palatini muscle (TVPM) inserted into the lateral lamina in the narrowest portion of the ET lumen in five of nine cases. These results suggest that contraction of the TVPM opens the narrowest portion of the ET lumen to ventilate the middle ear and that this portion also plays a role in protecting the middle ear.

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Computer-Aided Three-Dimensional Reconstruction and Measurement of the round Window and its Membrane

Otolaryngology ◽

10.1177/019459988910100501 ◽

1989 ◽

Vol 101 (5) ◽

pp. 517-521 ◽

Cited By ~ 15

Author(s):

Haruo Takahashi ◽

Akira Takagi ◽

Isamu Sando

Keyword(s):

Surface Area ◽

Round Window ◽

Three Dimensional ◽

Round Window Membrane ◽

Reconstruction Method ◽

Three Dimensional Reconstruction ◽

Maximal Diameter ◽

Computer Aided ◽

Dimensional Reconstruction ◽

Temporal Bones

This study was performed to clarify the complex three-dimensional shape of the round window and its membrane, and to measure these structures by using the computer-aided three-dimensional reconstruction method we developed. The equipment used included a personal computer, a high-resolution, 14-Inch color monitor, and a digitizer. Materials consisted of five normal temporal bones obtained from five individuals with negative otologic histories who had been 5 months and 14, 15, 18, and 59 years old at death. Round window membranes were found to be convex to the middle ear side when viewed in the coronal plane, but to be concave when viewed in the sagittal plane; thus the membrane in most cases seemed to be shaped like a saddle, tapered toward the vestibular end. The average maximal diameter, sagittal length, horizontal width, and surface area of the round window were 2.32 ± 0.19 mm, 2.08 ± 0.22 mm, 1.76 ± 0.10 mm, and 2.70 ± 0.43 mm2, respectively. The average surface area of the round window membrane was 2.98 ± 0.43 mm2.

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