Morphological Observations and Measurements on Main Canals in Temporal Bone of Chinese and Their Clinical Significance

Objective:To provide anatomical bases for the diagnosis and operative treatment of diseases of the structures in the canals of temporal bone. Methods:The data of each canal were obtained with probe and slide gaud. Results: The bony portion of auditory tube averages 10.40 mm in length, its tympanic opening has an average dimension of 4.46 mm × 3. 58 mm,and the average dimension of isthmic opening is 2.31 mm × 1.45 mm. The length of canal for greater petrosal nerve and of semicanal for tensor tympani is 13.93 mm and 11 . 86 mm respectively. The height of the vertical portion of carotid canal is 7. 51 mm,and it has the length of 15. 79 mm in its horizontal portion. The length of fissura petrosquamosa, squamotympanic fissure and petrotympanic rimule is 7.25 mm, 13. 88 mm and 5. 68 mm respectively. The distance between the opening of petrotympanic rimule on the external surface of the base of skull and the center of mandibular fossa averages 7.42 mm. Conclusion: It is important to avoid the damage to the adjoining structures close to the bony portion of auditory tube while transmastoid approach is applied to expand the lumen of auditory tube. Surgeon should be cautious of impairing greater petrosal nerve and geniculate ganglion when he segregates the dura over anterior surface of petrous part. The lesion of temporomandibular joint may affect the function of middle ear through the structures passing through petrotympanic rimule.