Where is the submental lymph node located?

• A. In the midline a few centimeters behind the tip of the mandible
• B. In front of the ear near the tragus
• C. Behind the mastoid process
• D. Along the anterior border of the sternocleidomastoid muscle

Answer: (A)

The main idea here is where the submental lymph nodes sit. They form the submental (unpaired) node group in the midline beneath the chin, between the two anterior bellies of the digastric muscles and just inferior to the mandible. This location puts them in the floor of the mouth area, a short distance behind the tip of the mandible. They drain lymph from the lower lip, chin, floor of the mouth, and the apex of the tongue, so infections in these areas often cause enlargement of these nodes.

This positioning helps distinguish them from other facial and neck nodes: nodes in front of the ear near the tragus are the preauricular/superficial parotid group, those behind the mastoid process are mastoid/occipital group, and nodes along the anterior border of the sternocleidomastoid are part of the superficial/deep cervical chains.