eRadiograph Volume 7: Imaging of Oral Cavity | Page 10

on either side of the midline with the neurovascular bundle lying lateral to the muscles. Genioglossus is seen very well on axial, sagittal and coronal images. Hyoglossus - This is a thin flat quadrilateral muscle which originates from the greater horn of hyoid bone, passes vertically to insert on either side of the tongue and is best seen on axial and coronal images, defining the lateral aspect of the tongue. The vascular bundle lies lateral to the hyoglossus muscle in the sublingual space. Invasion of the hyoglossus usually indicates vascular invasion. Styloglossus - This is a small muscle which originates from the styloid process between internal and external carotid arteries. This may be difficult to see on MRI, but is consistently seen on 3T images. Palatoglossus - This forms the anterior tonsillar pillar, arising from anterior surface of soft palate on each side of uvula passing downwards, forward and laterally to insert on posterolateral tongue. The genioglossus: pushes the tongue forward The hyoglossus: depresses and retracts the tongue The styloglossus: elevates and retracts tongue The palatoglossus: depresses the soft palate and elevates the back of the tongue. Lymphatic drainage: The tongue has a rich lymphatic drainage. The tip of the tongue drains to the submental nodes. The outer portion of the tongue drains to the submandibular and jugolodiagastric nodes. The central two thirds of the tongue unlike the vascular supply drain to both sides of the neck. This is of importance as a cancer extending 5 mm medial from the lateral margin is at risk of bilateral neck nodal metastases. The base of the tongue drains to the lymph nodes on either side of the neck. Floor of mouth: Floor of the mouth is a crescent shaped region lined by mucosa, bordered: - anteriorly by the lingual aspect of the lower gingiva - laterally by the alveolar ridge of the mandible 10 Imaging of Oral Cavity Vascular supply: The tongue is supplied by the lingual arteries. These paired arteries are branches of the external carotid artery. Each supplies each half of the tongue. The fibrofatty septum of the tongue prevents vascular anastomosis across the midline, however the tip of the tongue is supplied by both lingual arteries. One lingual artery can be sacrificed but if both are sacrificed there will be necrosis of the tongue, including the tip.