Submandibular Gland: Fullness Under the Jaw
- Highlighted area
Quick facts
- Location
- In the submandibular triangle, below the body of the mandible, between the two bellies of the digastric muscle.
- Function
- Produces much of the resting saliva; the submandibular duct opens onto the floor of the mouth, beside the frenulum of the tongue.
- Relations
- Facial artery in contact with the gland, facial vein outside it and the marginal mandibular branch above its capsule.
- With age
- It can descend and become visible as a lateral bulge under the jaw, especially in a thin neck.
- Relevance in HOF
- Differential diagnosis of the lateral double chin: it is not fat and does not respond to fat treatments.
The submandibular gland is one of the three major salivary glands, located below the body of the mandible, in the submandibular triangle of the neck, on each side. It produces much of the resting saliva and carries it to the mouth through the submandibular duct, which opens onto the floor of the mouth, beside the frenulum of the tongue. In HOF it matters because, with age or after weight loss, it can descend and show up as a lateral fullness under the jaw, mistaken for a double chin.
Where is it and what does it relate to?
| Structure | Relation to the gland |
|---|---|
| Digastric muscle | Its anterior and posterior bellies frame the triangle where the gland sits |
| Mylohyoid muscle | The gland wraps around its posterior edge, with a superficial part and a deep part |
| Platysma | Covers the gland on the outside, along with the cervical fascia |
| Facial artery | Runs in contact with the posterior and upper part of the gland before crossing the mandible |
| Facial vein | Runs outside the gland |
| Marginal mandibular branch | Runs above the gland's capsule, near the mandibular border |
| Lingual nerve and hypoglossal nerve | Deep relation, on the floor of the mouth |
The parotid gland sits behind, in front of the ear, and the two are sometimes confused by the patient when they speak of a "lump" at the angle of the jaw.
Why does it matter in HOF?
- Lateral double chin: the descended gland forms a bulge below the edge of the jaw, lateral to the submental area. It becomes more visible after neck fat is reduced, through weight loss or a procedure.
- Expectation: techniques aimed at submental fat, such as those discussed in enzymatic double chin lipolysis, do not act on the gland. If the fullness is glandular, promising a reduction through fat leads to frustration.
- Jawline: in some patients, the volume of the gland breaks the line between the angle and the chin, which enters the reading of the jawline.
The distinction between subcutaneous fat, subplatysmal fat, platysma and gland is covered in double chin: assessment.
How does it show up in the assessment?
- Profile and three-quarter view: the fullness sits below the mandibular border, on each side, with no continuity with the central double chin.
- Palpation: the gland is firmer than fat and cannot be pinched like skin with subcutaneous tissue.
- Platysma contraction: superficial fat moves with the muscle; glandular fullness stays underneath.
- Ultrasound: helps separate gland from fat and lymph node when there is doubt.
Also called: submaxillary gland, submandibular salivary gland.
Frequently asked questions
Can the submandibular gland look like a double chin?
It can. With age or after weight loss, the gland can descend and show as a lateral fullness under the jaw, on each side. Because it is a gland and not fat, procedures aimed at submental fat do not reduce it.
Is a swollen submandibular gland normal?
Swelling that grows when eating, pain, hardening, a lump or fast growth are not aesthetic findings. These signs call for a medical or dental assessment before any procedure in the area.