semicircular canals of bony labyrinth

sem·i·cir·cu·lar ca·nals of bo·ny la·by·rinth

(sem'ē-sĭr'kyū-lăr kă-nalz' bō'nē lab'i-rinth)
The organ of balance; the three bony tubes in the labyrinth of the ear within which the membranous semicircular ducts are located; they lie in planes at right angles to each other and are known as anterior semicircular canal, posterior semicircular canal, and lateral semicircular canal.