(seh'-mi-SEHR-kyoo-lawr caw-NAHL) One of three looping canals in each temporal bone that form a part of the inner ear. It contains perilymph fluid and the receptors for equilibrium.

The semicircular canals are three half-circular, interconnected tubes located inside each ear that are the equivalent of three gyroscopes located in three planes perpendicular. The vertical canals are positioned at an angle of about 100 degrees relative to one another, while the horizontal canal makes an angle of about 95 degrees with the posterior canal and an angle of about 110 degrees with the anterior canal. Deviations up to 10-15 degrees between individuals are normal.