Lymph nodes in the neck are small, bean-shaped structures that filter fluid and trap bacteria, viruses, and other harmful substances before they can spread through your body. Most adults have between 200 and 300 lymph nodes in the neck region alone, making it one of the densest concentrations of lymph nodes anywhere in the body. You can’t usually feel them, but when they swell in response to infection or other conditions, they become noticeable as firm, pea- or grape-sized lumps under your jaw, along the sides of your neck, or above your collarbone.
Where Neck Lymph Nodes Are Located
Neck lymph nodes (called cervical lymph nodes) are organized into distinct groups based on their position. Under your chin sit the submental nodes, while just beneath your jawbone on either side are the submandibular nodes. These are the ones you’re most likely to feel when you have a sore throat or dental infection.
Running along each side of your neck, following the large muscle that stretches from behind your ear to your collarbone, are three tiers of nodes: the upper, middle, and lower jugular nodes. The upper jugular nodes sit high, near the base of your skull. The middle group sits roughly at the level of your Adam’s apple, and the lower group extends down toward your collarbone. Behind that large neck muscle, in the back triangle of your neck, is another group called the posterior triangle nodes. Finally, just above the collarbone are the supraclavicular nodes, which have special clinical importance because of their connection to the chest and abdomen.
Each group primarily filters fluid from nearby tissues. The nodes under your jaw drain your mouth, teeth, and throat. The upper jugular nodes filter from the tongue, tonsils, and ear. This is why the location of a swollen node often points directly to where a problem started.
How Lymph Nodes Protect You
Lymph nodes are part of the lymphatic system, a network of thin-walled vessels that collect fluid from your tissues and return it to your bloodstream. As this fluid passes through a lymph node, immune cells inside the node scan it for anything foreign: bacteria, viruses, damaged cells, or other threats.
When a threat is detected, specialized immune cells called dendritic cells capture the invader and present it to T cells inside the node. This triggers T cells to activate and multiply, launching a targeted immune response. B cells in the node also get involved, producing antibodies tailored to that specific pathogen. This process is why your lymph nodes swell when you’re sick. They’re essentially ramping up production of immune cells and working overtime to filter out whatever is making you ill.
Why Neck Lymph Nodes Swell
The most common reason for swollen neck lymph nodes is an upper respiratory infection like a cold, flu, or sore throat. Viral infections are the leading cause, especially in children. These nodes typically become tender, slightly enlarged, and resolve on their own within a couple of weeks as the infection clears.
Bacterial infections can also cause swelling. Strep throat and staph infections tend to make nodes enlarge quickly and become quite painful. In some cases, the node itself can become infected and fill with fluid. Ear infections, dental abscesses, and skin infections on the face or scalp can all trigger nearby neck nodes to react.
Less common causes include:
- Mononucleosis (caused by Epstein-Barr virus), which often produces widespread neck node swelling along with extreme fatigue
- Cat-scratch disease, a bacterial infection from a cat scratch or bite that can cause nodes to stay swollen for months
- Autoimmune diseases, where the immune system mistakenly attacks healthy tissue
- Medication reactions, where certain drugs trigger lymph node enlargement as a side effect
- Cancer, either lymphoma (cancer of the lymphatic system itself) or metastatic cancer that has spread from another site
Normal Size vs. Enlarged
Healthy lymph nodes in the neck are typically too small and soft to feel. On imaging, nodes under about 6 millimeters across are generally considered normal in most areas of the neck. For the upper jugular region, where nodes tend to be naturally larger, up to 7 millimeters is typical. For context, 6 millimeters is roughly the size of a pencil eraser.
When nodes swell from a common infection, they might reach 1 to 2 centimeters (roughly the size of a pea to a small grape) and feel tender to the touch. Normal, reactive nodes are usually soft or slightly firm, movable under your fingers, and painful when pressed. These characteristics generally indicate your immune system is doing its job.
Signs That May Need Attention
Certain features of swollen lymph nodes are more concerning than others. Nodes that are hard, painless, and fixed in place (meaning they don’t move freely when you press on them) warrant closer evaluation. Cancer-related lymph node enlargement is typically painless, which is the opposite of what most people expect.
Swelling that persists for more than two to four weeks without an obvious infection is worth investigating, especially if it’s accompanied by unexplained weight loss, night sweats, or persistent fatigue. Nodes that keep growing over time rather than shrinking are also a reason to get checked.
Location matters too. Swollen nodes just above the collarbone (supraclavicular nodes) carry a higher level of concern than nodes under the jaw. Studies have found that 34% to 50% of patients with enlarged supraclavicular nodes had an underlying malignancy. A swollen node specifically on the left side above the collarbone, sometimes called Virchow’s node, has a well-documented association with cancers in the abdomen and pelvis. This connection was first described in 1848 and has been confirmed repeatedly since.
How Swollen Nodes Are Evaluated
If a swollen node looks suspicious based on its size, location, or how it feels, an ultrasound is often the first imaging step. Ultrasound can reveal several features that help distinguish harmless nodes from concerning ones. Normal lymph nodes have an oval shape and a bright, fatty center visible on the scan. Suspicious nodes tend to appear round, lack that fatty center, and may show abnormal blood flow patterns around their edges rather than through the middle.
Nodes with internal areas of dead tissue (necrosis) are particularly suggestive of malignancy, and this finding is common in nodes affected by squamous cell carcinomas of the head and neck. Blurry, ill-defined borders on imaging can suggest that abnormal cells have broken through the node’s outer capsule. Thyroid cancer that has spread to neck nodes can produce a distinctive appearance, with bright spots of calcification visible inside the node.
If imaging raises concern, a biopsy (removing a small sample of tissue from the node) provides a definitive answer. Supraclavicular nodes are often chosen for biopsy when present because they’re easy to access and frequently yield a diagnosis.
Swelling From Infection vs. Cancer
Most people who notice a swollen lymph node in their neck are dealing with an infection. This is especially true if the swelling appeared suddenly, is painful, and you have other symptoms like a sore throat, runny nose, or fever. Infection-related swelling is tender, somewhat soft, and usually affects nodes on both sides of the neck.
Cancer-related node enlargement tends to develop gradually, involves painless and firm nodes, and may appear on just one side. Lymphoma nodes often feel rubbery and can grow to be quite large. Nodes with metastatic cancer from a solid tumor (like throat or thyroid cancer) tend to feel rock-hard and may seem stuck to surrounding tissue.
Persistent swelling lasting several months without clear cause can also point to less common conditions like sarcoidosis or Kawasaki disease (the latter primarily in children). These aren’t cancerous but still require diagnosis and management.