The area commonly described as “under your chin” has a specific anatomical name: the submental region. Located centrally beneath the chin prominence (the mentum), this area is a distinct part of the neck and facial anatomy. The submental area is a focal point for both biological function and cosmetic interest, hosting important lymph nodes and muscles that define the contour of the lower face and neck.
The Submental Region
The submental region is anatomically defined by bony and muscular borders, forming a triangular space in the neck. Its superior boundary is the inferior border of the mandible. Inferiorly, the region is bounded by the hyoid bone.
Laterally, this space is delineated by the anterior bellies of the paired digastric muscles, which help to elevate the hyoid bone and depress the mandible during swallowing and chewing. The floor of this triangle is formed by the mylohyoid muscle, a broad, flat muscle that acts as the muscular diaphragm of the mouth. This anatomical arrangement is sometimes referred to as the submental triangle.
Submental Fullness and Appearance
Submental fullness, often called a “double chin,” is a common concern resulting from the accumulation of subcutaneous fat tissue directly beneath the skin. This excess fat obscures the defined angle between the jawline and the neck, leading to an older or heavier appearance. Genetic predisposition plays a significant role in where the body stores fat, meaning some individuals may develop submental fullness even without being overweight. Aging also contributes, as the skin loses collagen and elastin, leading to skin laxity and sagging that amplifies the appearance of a double chin.
Because this fullness is often resistant to diet and exercise alone, it is a frequent target for cosmetic procedures. Surgical options, such as liposuction, physically remove the excess fat deposits to improve contour. Non-surgical treatments include injectable medications that use deoxycholic acid, a natural molecule that breaks down fat cells in the targeted area.
Key Underlying Structures
The submental region houses several biologically relevant components. The most notable contents within the submental triangle are the submental lymph nodes. These small glands filter lymph fluid that drains from the tip of the tongue, the lower lip, the floor of the mouth, and the lower incisor teeth.
The presence of these nodes makes the submental region medically important, as swelling can indicate an infection or inflammation in the structures they drain. The mylohyoid and digastric muscles forming the boundaries of the space are part of a group called the suprahyoid muscles. These muscles are responsible for elevating the hyoid bone and the tongue for swallowing and speaking.
The region also contains the submental veins and the termination of the submental arteries, which supply blood to the muscles and tissues in the area. The submandibular salivary glands are located immediately adjacent in the submandibular space, often contributing to the overall perception of the area under the chin.