Which extrinsic tongue muscle is primarily responsible for retraction (pulling back) of the tongue?

The styloglossus muscle originates from the styloid process of the temporal bone and inserts into the posterolateral tongue. Its primary action is retraction (pulling the tongue posteriorly and superiorly) and elevation of the lateral tongue edges. In contrast: genioglossus is the primary tongue protruder (protrudes and depresses tongue); hyoglossus depresses and retracts the tongue; palatoglossus elevates the posterior tongue and depresses the soft palate. All extrinsic tongue muscles (except palatoglossus) are innervated by the hypoglossal nerve (CN XII); palatoglossus is innervated by the vagus nerve (CN X) via the pharyngeal plexus.