The superior and inferior colliculi of the mesencephalic tectum (roof) in the brain.
(L. geminus, a twin; quadri, four + bodies): Term applied to the four protuberances on the dorsal surface of the midbrain; the two superior and two inferior colliculi.
In the brain, the corpora quadrigemina (Latin for "quadruplet bodies") are the four colliculi—two inferior, two superior—located on the posterior aspect of the midbrain.