The sensation of posterior aspect of tongue is by

The glossopharyngeal nerve is the nerve for both general sensation and taste for the posterior one third of the tongue including the circumvallate papillae.The posterior most pa of the tongue is supplied by the vagus nerve through the internal laryngeal branch.The sensory supply of anterior two thirds is lingual nerve where as the taste sensation from the anterior two thirds is carried out by chorda tympani except vallate papillae(pre-trematic branch of first arch). REF.BDC VOL 3,Fifth edition.