The region between the mandible and the hyoid bone that contains the submandibular and sublingual glands, suprahyoid muscles, submandibular ganglion, and lingual artery. [ https://github.com/obophenotype/uberon/issues/1137 ]
Term information
https://upload.wikimedia.org/wikipedia/commons/thumb/3/36/Musculi_coli_base%2C_my_edits_for_tringles%2C_labeled_triangles%2C_Submandib.svg/500px-Musculi_coli_base%2C_my_edits_for_tringles%2C_labeled_triangles%2C_Submandib.svg.png
we place submandibular triangle from FMA here, although this may be a narrower region with more precise boundaries
trigonum submandibulare
digastric triangle
submaxillary triangle
submandibular triangle