Clinical anatomic observation of internal acoustic meatus and related structures on multi-slice spiral CT images

Abstract

Objective To observe the morphologic features of normal fundus of internal acoustic meatus and its related structures on multi-slice spiral CT images. Methods The morphologic features of transverse crests, labyrinth segment of facial nerve canal(FNC), superior vestibular nerve canal(SVNC), inferior vestibular nerve canal(IVNC) and posterior ampulla nerve canal (PANC) were described on MSCT images of 80 ears (40 adults), with the lengths and diameters of these canals, the distance from the transverse crest to the vestibule (D1), and from the singular foramen to the medial wall of vestibule (D2) measured, respectively. Results The labyrinth segment of FNC, the SVNC, IVNC and PANC were all visible on the multi-slicp spiral CT images of the 80 ears. The mean length/diameter of labyrinth segment of FNC, the SVNC, IVNC and PANC were (2.60±0.34)mm/(0.91±0.23)mm, (3.39±0.52)mm/(1.03±0.19)mm, (1.35±0.27)mm/(1.34±0.25)mm, and (3.88±0.84)mm/(0.63±0.12)mm, respectively. The mean D1 was (1.56±0.55) mm. The mean D2 was (2.50±0.72)mm. The medial edges of transverse crests were curved. Conclusions The morphologic features of the labyrinth segment of FNCs, SVNCs, IVNCs, PANCs and transverse crests can be clearly displayed on multi-slicp spiral CT images, which provide helpful information for the differential diagnosis and management of lesions in fundus of internal acoustic meatus. Key words: Ear, inner; Fundus of internal acoustic meatus; Transverse crest; Vestibular nerve; Anatomy; Tomography, spiral computed