Posterior semicircular canal

Canalis semicircularis posterior

Sensory (eye & ear)OrgansHeadLeft and right

View left in 3D View right in 3D

What it is

The posterior semicircular canal lies in a vertical plane parallel to the long axis of the petrous bone, the most posterior of the three, with its ampulla at the lower end.

Function

Senses rotation in its plane: tilting the head toward the shoulder combined with pitch.

Size

Radius about 3.2-4 mm; the longest canal, about 20 mm.

Clinical note

The canal most often affected by benign positional vertigo, because loose otoconia settle into its lowest point.