Ultrasonic assessment of the anatomy and function of the tongue.

The tongue is a complex muscular structure. Apart from its intrinsic strength, it has a major influence on the adjacent bony structures. Real time ultrasound appears to be the method of choice for assessing the topographic and functional anatomy. The examination was performed using an Acuson 128 scanner, with a 5 MHz probe, either a sector scanner (sagittal plane) or linear array probe (coronal plane). The scans were performed using the sub-hyoid approach, between the rami of the mandible. The images were stored on U-matic videotape. Thirty adult patients were included in the study population. The scan protocol consisted of an examination of the tongue at rest, a scan of the swallowing mechanism with and without a liquid bolus and a study of the posterior lingual positions (which show some anatomical variation). The intrinsic muscles of the tongue and the floor of the mouth could be identified on the "at rest" images. The lingual mass is the most important parameter and is opposed against the palate in order to propel a bolus during the swallowing mechanism. The mobility, shape and supporting structures of the tongue are variable depending on the nature of the bolus, the patient and the two imaging planes. Ultrasound is a simple and non-invasive method for the examination of the buccal cavity. The function of the posterior portion of the tongue must be taken into consideration prior to any treatment concerning the oral cavity.