The Clinical Syndrome
An uncommon cause of facial pain, Eagle syndrome (also known as stylohyoid syndrome) is caused by pressure on the internal carotid artery and surrounding structures, including branches of the glossopharyngeal nerve, by an abnormally elongated styloid process, a calcified stylohyoid ligament, or both. The pain of Eagle syndrome is sharp and stabbing and occurs with movement of the mandible or turning of the neck. The pain starts below the angle of the mandible and radiates into the tonsillar fossa, temporomandibular joint, and base of the tongue. A trigger point may be present in the tonsillar fossa. Injection of the attachment of the stylohyoid ligament to the styloid process with local anesthetic and steroid serves as a diagnostic maneuver and a therapeutic maneuver.
Signs and Symptoms
Eagle syndrome is most often a diagnosis of exclusion. Patients suffering from Eagle syndrome present with a history of sudden, sharp neuritic pain that begins below the angle of the mandible and radiates into the tonsillar fossa, temporomandibular joint, and base of the tongue. The pain is triggered by swallowing, movement of the mandible, or turning of the neck ( Fig. 15.1 ). The intensity of pain is moderate to severe and unpleasant. The neurological examination is normal. The pain of Eagle syndrome may be triggered by palpation of the tonsillar fossa.
In patients with Eagle syndrome, radiographs and computed tomography (CT) scans of the region of the styloid process show an elongated styloid process that is often associated with a calcified stylohyoid ligament ( Fig. 15.2 ). The diagnosis of Eagle syndrome may be strengthened by a diagnostic injection of the attachment of the stylohyoid ligament to the styloid process with local anesthetic. Pain relief after this injection suggests a local cause for the pain rather than a more distant cause, such as glossopharyngeal neuralgia or retropharyngeal tumor ( Fig. 15.3 ).