The submental triangle defines a sub-region of the anterior cervical region (anterior triangle of the neck). It is one of four smaller triangles within the anterior triangle of the neck. With those four smaller triangles, a more precise localization of structures within the anterior cervical region of the neck is achieved. The other three triangles are the submandibular, carotid, and muscular. These three triangles are paired, because they are found on both sides of the midline, but the submental is unpaired and sits on the midline just inferior to the chin.
The submental triangle, also referred to as the suprahyoid triangle, is an unpaired suprahyoid area lying inferior to the chin. It is limited by the body of the hyoid bone inferiorly, laterally by the right and left anterior bellies of the digastric muscles. These bellies of the digastrics muscle taper superiorly and forward towards the apex of the triangle. The apex of the submental triangle is at the mandibular symphysis, the site of union of the halves of the mandible during the early years of life. The hyoid bone forms the base of the triangle, while the roof is formed by the two mylohyoid muscles, which meet in a median fibrous raphe.
The submental triangle is not a clinically significant space. Its involvement with congenital lesions of the head and neck, or any form of inflammation, is relatively uncommon compared with the prevalence of such lesions in other cervical regions.
Although the submental triangle is a superficial region, it houses some important structures, such as:
- the mylohyoid nerve
- lymph glands
- several small lymph nodes, called submental lymph nodes
- some small veins which unite to form the anterior jugular vein.
- submental branches of the facial artery
- submental branches of the facial vein