Table 5.
Negative values | Positive values |
---|---|
PC1 | |
Shorter and slightly curved common crus | Longer and more straight common crus |
Circular anterior canal | Oval anterior canal |
Smaller angle between lateral and anterior canals (< 90°) | Larger angle between lateral and anterior canals |
Lateral canal concave anteriorly | Lateral canal convex anteriorly |
Smaller lateral canal | Long U‐shaped lateral canal |
More dorsal position of the posterior branch of the lateral canal relative to the posterior ampulla | Less dorsal position of the posterior branch of the lateral canal relative to the posterior ampulla |
Posterior canal more extended laterally and shorter dorsally | Posterior canal more extended dorsally and shorter laterally |
Laterally compressed vestibule | Laterally wider vestibule |
Lower cochlea | Higher cochlea |
Greater degree of curvature of the cochlea | Lesser degree of curvature of the cochlea |
Cochlea pointing more ventrally in anterior view | Cochlea pointing more anteriorly in anterior view |
PC2 | |
Shorter common crus | Longer common crus |
Higher angle between lateral and anterior canals | Smaller angle between lateral and anterior canals (< 90°) |
Straight lateral canal | Lateral canal concave laterally and convex anteriorly |
Circular lateral canal | Maximum axis of the lateral canal displaced posteriorly |
Lack of secondary common crus | Presence of secondary common crus |
Smaller angle between posterior and lateral canals (< 90°) | Higher angle between posterior and lateral canals |
Higher angle between posterior and anterior canals | Smaller angle between posterior and anterior canals |
Laterally wide vestibule | Laterally compressed vestibule |
Wider and lower cochlea | Narrower and higher cochlea |
Greater degree of curvature of the cochlea | Lesser degree of curvature of the cochlea |
Cochlea pointing more medially in anterior view | Cochlea pointing more anteriorly and laterally in anterior view |
PC3 | |
Slightly curved common crus | More straight common crus |
Lateral canal convex anteriorly and concave laterally | Lateral canal concave anteriorly and convex laterally |
Higher angle between anterior and posterior canals (≥ 90°) | Smaller angle between anterior and posterior canals (< 90°) |
Lateral canal more laterally extended | Lateral canal less laterally extended |
Posterior canal less laterally extended | Posterior canal more laterally extended |
More lateral connection between lateral and posterior canals | More medial connection between lateral and posterior canals |
Smaller angle between posterior and anterior canals | Higher angle between posterior and anterior canals |
Wider and lower cochlea | Narrower and higher cochlea |
Greater degree of curvature of the cochlea | Lesser degree of curvature of the cochlea |
Cochlea pointing more ventrally in anterior view | Cochlea pointing more anteriorly in anterior view |
See Fig. 5 for illustration.