[TA] arises from an oblong nucleus in the medulla and emerges by several root filaments between the pyramid and the olive via the preolivary groove; it passes through the hypoglossal canal, then courses downward and forward to supply the intrinsic and four of five extrinsic muscles of the tongue. SYN: nervus hypoglossus [CN XII] [TA], twelfth cranial nerve [CN XII].
