The lymphatic system serves as the body’s drainage and surveillance network, playing a role in immune defense by filtering fluid and identifying threats. This network includes specialized filtering stations called lymph nodes, positioned strategically across the body to trap foreign particles and infectious agents. Among the many clusters of these nodes, the submandibular group is important due to its location in the head and neck, where it monitors health issues affecting the mouth and throat.
Precise Anatomical Location
The submandibular lymph nodes are situated beneath the lower jawbone, or mandible, making them easily accessible for examination. They reside within a distinct area of the neck known as the submandibular triangle, which is bordered by the inferior edge of the mandible above and two muscles of the neck below. These nodes are found roughly halfway between the point of the chin and the angle where the jaw turns upward toward the ear.
These nodes are typically found in a small cluster, with most people having between three and six individual nodes. They are often located directly next to the submandibular salivary gland, and sometimes one or more nodes can even be embedded within the gland tissue itself. In a healthy state, they are quite small, generally measuring around one centimeter or less, which makes them soft and difficult to feel.
Regions Drained by the Submandibular Nodes
The submandibular nodes collect and filter lymph fluid from numerous structures in the lower face and mouth, including the floor of the mouth. They also receive lymph from the cheeks, the upper lip, and the lateral portions of the lower lip.
These nodes filter fluid from the oral cavity’s hard and soft tissues, including the following areas:
- The front section and sides of the tongue.
- The gums and most of the teeth (excluding the lower incisors and back molars).
- The submental lymph nodes.
- The facial lymph nodes, making them a major collector for the entire lower face.
Clinical Significance of Swelling
When the submandibular lymph nodes become enlarged, a condition known as lymphadenopathy, it is usually an indication that the body is fighting off a challenge. Common causes of swelling are infections in the mouth, throat, or face, such as dental abscesses, severe gingivitis, or upper respiratory tract infections like a cold or strep throat. The nodes swell as immune cells multiply rapidly inside the node to combat the infectious agents that have been filtered from the lymph fluid.
In a typical infection, the nodes are often tender, hot, and mobile. Persistent swelling can signal a more serious underlying issue. Malignancies like lymphoma or metastatic cancer from the oral cavity or salivary gland can also cause the nodes to enlarge. A medical evaluation is warranted if the swelling is unilateral, remains hard and fixed in place, or is accompanied by systemic symptoms like unexplained weight loss or prolonged fever.
Practical Guide to Self-Checking
Regularly checking the submandibular area can help a person become familiar with what their normal nodes feel like. To check, use the soft pads of the fingertips and apply a gentle, circular motion along the underside of the jawbone. Start near the chin and follow the curve of the mandible back toward the ear on both sides, comparing the feel of the left and right sides.
In a healthy state, the nodes may be imperceptible, or they may feel like small, soft, movable pebbles or beans. If the nodes are temporarily enlarged due to a recent infection, they will feel tender and somewhat rubbery. However, if a swollen node persists for more than two weeks, or if it feels hard, fixed, and painless, it is important to seek medical advice.