structural:scholar_edition
Lateral semicircular canal

It measures from 12 to 15 mm (0.47 to 0.59 in), and its arch is directed horizontally backward and laterally; thus each semicircular canal stands at right angles to the other two. Its ampullated end corresponds to the upper and lateral angle of the vestibule, just above the oval window, where it opens close to the ampullated end of the anterior semicircular canal; its opposite end opens at the upper and back part of the vestibule. The lateral canal of one ear is very nearly in the same plane as that of the other.