The styloglossus runs from the styloid process to the lateral tongue, forming the lateral boundary of the parapharyngeal space. Together with hyoglossus and genioglossus, it is one of the three extrinsic tongue muscles supplied by CN XII. Its retraction function is essential in the oral phase of swallowing and in maintaining the tongue against the palate during normal phonation.
| Origin | Anterior surface of the styloid process of the temporal bone and upper stylohyoid ligament |
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| Insertion | Along the lateral margin of the tongue, interdigitating with the hyoglossus; fibers spread to the tongue tip |
| Nerve Supply | Hypoglossal nerve (CN XII) |
| Blood Supply | Lingual artery branches |
| Actions | Retracts and elevates the tongue (pulls the tongue posteriorly and superiorly); contributes to tongue shaping during swallowing, particularly in the pharyngeal phase where it helps drive the bolus posteriorly |
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The styloglossus is relevant in parapharyngeal space surgery where it defines the posterior boundary of the prestyloid parapharyngeal compartment. Styloid process elongation (Eagle syndrome) may cause styloglossus-related throat pain and dysphagia. CN XII monitoring during carotid endarterectomy and parotidectomy must account for its branch to styloglossus. Hypoglossal nerve palsy produces ipsilateral tongue deviation toward the paralysed styloglossus side on protrusion.
Hypoglossal nerve traction or ligation during carotid endarterectomy for carotid bifurcation plaque produces ipsilateral styloglossus and tongue paralysis with tongue deviation to the affected side on protrusion, causing dysphagia and dysarthria; the nerve is identified crossing the carotid bifurcation and protected by meticulous dissection.
