OBJECTIVE: Measure the space direction of semicircular canals to provide the anatomical basis for the diagnosis and treatment of BPPV. METHOD: We calculated angles among semicircular canals of 24 patients using MRI scaning with 3D-CISS sequence. RESULT: The angle between the left and right posterior semicircular canals was 106.61 degress ± 8.58 degrees, so the angle among the posterior semicircular canals and sagittal head plane was 53.31 degrees ± 4.29 degrees. Pairs of contralateral synergistic canal planes were not parallel, forming 171.67 degrees ± 4.36 degrees between the left and right horizontal semicircular canal planes, 154.37 degrees ± 10.87 degrees between the left posterior and right anterior semicircular canal planes and 156.84 degrees ± 9.34 degrees between the right posterior and left anterior semicircular canal planes. CONCLUSION Our measurement of the angles among semicircular canals coincided with those of previous reports. The angles between contralateral synergistic canal planes were close to parallel, but the angle between the posterior semicircular canals and sagittal head plane was great than 45 degrees that traditionally thought to be.
Humans ; Magnetic Resonance Imaging ; Semicircular Canals ; anatomy & histology

OBJECTIVESTo explore shape and position relationship of the structures with in sinus triangle region, and provide the anatomic foundation for extended presigmoid operative approach.

METHODSTen cadaveric heads and 15 skull-base specimens fixed with 10% formalin, with aid of operative microscope, the shape and relations of structures with in the sinus triangle region were observed and microphotographed. Four cadaveric heads were sectioned in different plane using collodion embedding process.

RESULTSJugular blub (JB) had high -placed jugular blub (HJB), normal jugular blub (NJB) and low-placed jugular blub (LJB). The incidence of HJB was 8% and 18% for the left and right sides (P < 0.01). The JB dome can extend upward the hypotympanic cavity and the posterior wall of the internal acoustic meatus. The incidence of NJB and LJB was 36% and 30%, and 6% and 2% respectively. The level distance between the posterior semicircular canal and petrosal posterior surface was (4.1 +/- 1.1) mm. The distance between the JB and vertical part of the facial nerve was (3.2 +/- 0.5) mm and (2.0 +/- 0.4) mm. The distance between the JB and posterior margin of the internal acoustic port was (7.5 +/- 1.7) mm and (4.0 +/- 1.0) mm.

CONCLUSIONSKnowing the shape and position relationship of structures in the sinus triangle region is favorable for preserving the important structures in extended presigmoid operative approach.

Autopsy ; Cadaver ; Cranial Sinuses ; anatomy & histology ; Glomus Jugulare ; anatomy & histology ; Humans ; Neuroanatomy ; Semicircular Canals ; anatomy & histology

OBJECTIVE: To evaluate the safety of the circular round window and discus anatomic landmarks of posterior wall of internal auditory canal by investigating the microscopic anatomy of internal auditory canal area of the retrosigmold approach, which can provide the anatomical basis for acoustic neutrinomas surgery. METHOD: Fifteen adult cadaver heads (30 sides) fixed with formalin were used in the study. The retrosigmold approach operations were imitated to dissect the blood vessels and nerves in internal auditory canal area by opening round bony window and removing posterior wall of internal auditory canal. RESULT: Fifteen specimens of 30 sides circular bone window were opened without injury with transverse sinus and sigmoid sinus. The vertical distance between the highest point of bone window margo superior and the lowest point of transverse sinus margo inferior was (4.02 ± 0.32) mm. The vertical distance from the most anterior point of bone window leading edge to the most posterior point of sigmoid sinus trailing edge was (6.31 ± 0.43) mm. The internal auditory canal tubercle located in the anterior superior position of internal auditory canal. The vertical distance from the highest point of internal auditory canal tubercle to the upper margin of internal auditory canal was (2.31 ± 0.32) mm. To expose the whole internal auditory canal, the length and width of the internal auditory canal posterior wall removal was (7.29 ± 0.32) mm, (4.12 ± 0.29) mm. Within this removal range, no case of cochlea, semicircular canal or venous was injured in 30 specimens. CONCLUSION The method of opening round window through retrosigmold approach is simple, practial and convenient. With little variation and easiness of location, the sinternal auditory canal tubercle can be used in the identification of the internal auditory canal. When exposing the whole internal auditory canal, the removal scope of the posterior wall should be paid more attention to, in order to avoid the damage of cochlea, semicircular canal and jugular bulb.
Adult ; Cranial Sinuses ; Ear Canal ; Ear, Inner ; Humans ; Round Window, Ear ; anatomy & histology ; Semicircular Canals ; anatomy & histology ; Temporal Bone

OBJECTIVE: To compare the use of 3D driven equilibrium (DRIVE) imaging with 3D balanced fast field echo (bFFE) imaging in the assessment of the anatomic structures of the internal auditory canal (IAC) and inner ear at 3 Tesla (T). MATERIALS AND METHODS: Thirty ears of 15 subjects (7 men and 8 women; age range, 22-71 years; average age, 50 years) without evidence of ear problems were examined on a whole-body 3T MR scanner with both 3D DRIVE and 3D bFFE sequences by using an 8-channel sensitivity encoding (SENSE) head coil. Two neuroradiologists reviewed both MR images with particular attention to the visibility of the anatomic structures, including four branches of the cranial nerves within the IAC, anatomic structures of the cochlea, vestibule, and three semicircular canals. RESULTS: Although both techniques provided images of relatively good quality, the 3D DRIVE sequence was somewhat superior to the 3D bFFE sequence. The discrepancies were more prominent for the basal turn of the cochlea, vestibule, and all semicircular canals, and were thought to be attributed to the presence of greater magnetic susceptibility artifacts inherent to gradient-echo techniques such as bFFE. CONCLUSION: Because of higher image quality and less susceptibility artifacts, we highly recommend the employment of 3D DRIVE imaging as the MR imaging choice for the IAC and inner ear.
Adult ; Aged ; Cochlea/anatomy & histology ; Ear, Inner/*anatomy & histology ; Female ; Humans ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging/*methods ; Male ; Middle Aged ; Semicircular Canals/anatomy & histology ; Vestibule, Labyrinth/anatomy & histology