### Abstract

Analysis of vestibulo-ocular reflex experiments requires knowledge of the absolute orientations (with respect to skull landmarks) of semicircular canals (SCC). Data relating SCC orientations to accessible skull landmarks in humans are sparse, apart from a classic study of 10 skulls, which concluded that the horizontal and anterior SCC are not mutually orthogonal (111 ± 7.6°). Multiple studies of isolated labyrinths have shown the inter-SCC angles are close to 90°. We hypothesized that a larger sample would yield mean absolute SCC orientations closer to the mutual orthogonality demonstrated for isolated labyrinths. We measured canal orientations with respect to accessible skull landmarks using 3-D multiplanar reconstructions of computerized tomography scans of the temporal bones of 22 human subjects. Images were acquired with 0.5-mm thickness and reconstructed with in-plane resolution of 234 μm. There was no significant difference between the left and a mirror image of the right (p > 0.57 on multiway ANOVA of orientation vector coefficients), so data were pooled for the 44 labyrinths. The angle between the anterior and posterior SCC was 94.0 ± 4.0° (mean ± SD). The angle between the anterior and horizontal SCC was 90.6 ± 6.2°. The angle between the horizontal and posterior SCC was 90.4 ± 4.9°. The direction angles between a vector normal to the left horizontal SCC and the positive Reid's stereotaxic X (+nasal), Y (+left), and Z (+superior) axes were 108.7 ± 7.5°, 92.2 ± 5.7°, and 19.9 ± 7.0°, respectively. The angles between a vector normal to the left anterior SCC and the positive Reid's stereotaxic X, Y, and Z axes were 125.9 ± 5.2°, 38.4 ± 5.1°, and 100.1 ± 6.2°, respectively. The angles between a vector normal to the left posterior SCC and the positive Reid's stereotaxic X, Y, and Z axes were 133.6 ± 5.3°, 131.5 ± 5.1°, and 105.6 ± 6.6°, respectively. The mean anterior SCC-contralateral posterior SCC angle was 15.3 ± 7.2°. The absolute orientations of human SCC are more nearly orthogonal than previously reported.

Original language | English (US) |
---|---|

Pages (from-to) | 191-206 |

Number of pages | 16 |

Journal | JARO - Journal of the Association for Research in Otolaryngology |

Volume | 6 |

Issue number | 3 |

DOIs | |

State | Published - Sep 2005 |

### Fingerprint

### Keywords

- Computed tomography
- CT
- Labyrinth
- Orientation
- Semicircular canal
- Vestibular
- VOR

### ASJC Scopus subject areas

- Otorhinolaryngology
- Physiology

### Cite this

*JARO - Journal of the Association for Research in Otolaryngology*,

*6*(3), 191-206. https://doi.org/10.1007/s10162-005-0003-x

**Orientation of human semicircular canals measured by three-dimensional multiplanar CT reconstruction.** / Della Santina, Charles Coleman; Potyagaylo, Valeria; Migliaccio, Americo A.; Minor, Lloyd B.; Carey, John P.

Research output: Contribution to journal › Article

*JARO - Journal of the Association for Research in Otolaryngology*, vol. 6, no. 3, pp. 191-206. https://doi.org/10.1007/s10162-005-0003-x

}

TY - JOUR

T1 - Orientation of human semicircular canals measured by three-dimensional multiplanar CT reconstruction

AU - Della Santina, Charles Coleman

AU - Potyagaylo, Valeria

AU - Migliaccio, Americo A.

AU - Minor, Lloyd B.

AU - Carey, John P

PY - 2005/9

Y1 - 2005/9

N2 - Analysis of vestibulo-ocular reflex experiments requires knowledge of the absolute orientations (with respect to skull landmarks) of semicircular canals (SCC). Data relating SCC orientations to accessible skull landmarks in humans are sparse, apart from a classic study of 10 skulls, which concluded that the horizontal and anterior SCC are not mutually orthogonal (111 ± 7.6°). Multiple studies of isolated labyrinths have shown the inter-SCC angles are close to 90°. We hypothesized that a larger sample would yield mean absolute SCC orientations closer to the mutual orthogonality demonstrated for isolated labyrinths. We measured canal orientations with respect to accessible skull landmarks using 3-D multiplanar reconstructions of computerized tomography scans of the temporal bones of 22 human subjects. Images were acquired with 0.5-mm thickness and reconstructed with in-plane resolution of 234 μm. There was no significant difference between the left and a mirror image of the right (p > 0.57 on multiway ANOVA of orientation vector coefficients), so data were pooled for the 44 labyrinths. The angle between the anterior and posterior SCC was 94.0 ± 4.0° (mean ± SD). The angle between the anterior and horizontal SCC was 90.6 ± 6.2°. The angle between the horizontal and posterior SCC was 90.4 ± 4.9°. The direction angles between a vector normal to the left horizontal SCC and the positive Reid's stereotaxic X (+nasal), Y (+left), and Z (+superior) axes were 108.7 ± 7.5°, 92.2 ± 5.7°, and 19.9 ± 7.0°, respectively. The angles between a vector normal to the left anterior SCC and the positive Reid's stereotaxic X, Y, and Z axes were 125.9 ± 5.2°, 38.4 ± 5.1°, and 100.1 ± 6.2°, respectively. The angles between a vector normal to the left posterior SCC and the positive Reid's stereotaxic X, Y, and Z axes were 133.6 ± 5.3°, 131.5 ± 5.1°, and 105.6 ± 6.6°, respectively. The mean anterior SCC-contralateral posterior SCC angle was 15.3 ± 7.2°. The absolute orientations of human SCC are more nearly orthogonal than previously reported.

AB - Analysis of vestibulo-ocular reflex experiments requires knowledge of the absolute orientations (with respect to skull landmarks) of semicircular canals (SCC). Data relating SCC orientations to accessible skull landmarks in humans are sparse, apart from a classic study of 10 skulls, which concluded that the horizontal and anterior SCC are not mutually orthogonal (111 ± 7.6°). Multiple studies of isolated labyrinths have shown the inter-SCC angles are close to 90°. We hypothesized that a larger sample would yield mean absolute SCC orientations closer to the mutual orthogonality demonstrated for isolated labyrinths. We measured canal orientations with respect to accessible skull landmarks using 3-D multiplanar reconstructions of computerized tomography scans of the temporal bones of 22 human subjects. Images were acquired with 0.5-mm thickness and reconstructed with in-plane resolution of 234 μm. There was no significant difference between the left and a mirror image of the right (p > 0.57 on multiway ANOVA of orientation vector coefficients), so data were pooled for the 44 labyrinths. The angle between the anterior and posterior SCC was 94.0 ± 4.0° (mean ± SD). The angle between the anterior and horizontal SCC was 90.6 ± 6.2°. The angle between the horizontal and posterior SCC was 90.4 ± 4.9°. The direction angles between a vector normal to the left horizontal SCC and the positive Reid's stereotaxic X (+nasal), Y (+left), and Z (+superior) axes were 108.7 ± 7.5°, 92.2 ± 5.7°, and 19.9 ± 7.0°, respectively. The angles between a vector normal to the left anterior SCC and the positive Reid's stereotaxic X, Y, and Z axes were 125.9 ± 5.2°, 38.4 ± 5.1°, and 100.1 ± 6.2°, respectively. The angles between a vector normal to the left posterior SCC and the positive Reid's stereotaxic X, Y, and Z axes were 133.6 ± 5.3°, 131.5 ± 5.1°, and 105.6 ± 6.6°, respectively. The mean anterior SCC-contralateral posterior SCC angle was 15.3 ± 7.2°. The absolute orientations of human SCC are more nearly orthogonal than previously reported.

KW - Computed tomography

KW - CT

KW - Labyrinth

KW - Orientation

KW - Semicircular canal

KW - Vestibular

KW - VOR

UR - http://www.scopus.com/inward/record.url?scp=33644871340&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33644871340&partnerID=8YFLogxK

U2 - 10.1007/s10162-005-0003-x

DO - 10.1007/s10162-005-0003-x

M3 - Article

VL - 6

SP - 191

EP - 206

JO - JARO - Journal of the Association for Research in Otolaryngology

JF - JARO - Journal of the Association for Research in Otolaryngology

SN - 1525-3961

IS - 3

ER -