abnormal extrinsic tongue muscle morphology abnormal hyoglossus muscle morphology 2017-09-28T09:57:57Z abnormal hyoglossus morphology MPheno.ontology any structural anomaly of the thin, quadrilateral extrinsic tongue muscle that arises from the side of the body and from the whole length of the greater cornu of the hyoid bone, and passes almost vertically upward to enter the side of the tongue, between the styloglossus and the inferior longitudinal muscle of the tongue; its action depresses and retracts the tongue and makes the dorsum more convex MP:0030212