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[Three-dimensional reconstruction of internal auditory meatus and anatomical study of the inner structures]
1Department of Otorhinolaryngology, Nanfang Hospital, First Military Medical University, Guangzhou 510515, China. chhx@fimmu.edu.cn
Objective:
To provide anatomical basis for surgical operation in internal auditory meatus (IAM).
Methods:
Structures of cerebellopontine angle (CPA) and IAM in 25 temporal bone specimens (50 sides) fixed in formalin were measured. Three-dimensional reconstruction (3DR) of IAM in 13 normal adults (26 sides) was conducted using spiral CT scanning.
Results:
IAM took a conic shape with larger inside and smaller outside. The average width of IAM was (4.16 +/- 1.23) mm(2.87-6.83 mm) in horizontal dimension, the average height was (3.14 +/- 1.01) mm(2.23-4.45 mm) in vertical dimension, the average length was (8.67 +/- 2.31) mm (6.77-11.22 mm), the average volume was (98.23 +/- 16.56) mm3(67.44-133.21 mm3). There were 1-4 internal auditory arteries branched from the anterior-inferior cerebellar artery, which formed a vascular ansa near the opening of IAM. The average length of the facial nerve in IAM was (0.98 +/- 0.03) mm (0.89-1.07 mm), the average diameter of vestibulocochlear nerve was (1.67 +/- 0.05) mm (1.42-1.97 mm), the average diameter of the intermediate nerve (0.23 +/- 0.02) mm (0.19-0.26 mm).
Conclusion:
It is necessary to pay attention to types of vascular ansa and relative nerve location in IAM during operation.