Lymph nodes in the neck are small, bean-shaped organs that filter fluid flowing through your body and trap harmful invaders like bacteria and viruses. You have roughly 300 lymph nodes in your head and neck region alone, making it one of the most lymph-node-dense areas of your body. Most of the time you can’t feel them at all, but when they swell during an infection, they become noticeable and sometimes tender.
What Lymph Nodes Actually Do
Your bloodstream constantly leaks a clear fluid called lymph into surrounding tissues. This fluid carries proteins, nutrients, and cellular waste, but it also picks up bacteria, viruses, damaged cells, and even cancer cells along the way. Lymph nodes act as checkpoints. As lymph flows through them, immune cells stationed inside identify and destroy anything that doesn’t belong.
Each node has a layered structure. A tough outer shell (the capsule) protects the interior, where different types of immune cells are concentrated. B cells produce antibodies that tag foreign invaders. T cells directly attack infected or abnormal cells. Other immune cells called macrophages essentially swallow and digest debris. When your body is fighting off an infection near your head or throat, these nodes ramp up their activity, which is why they swell and sometimes hurt.
Where Neck Lymph Nodes Are Located
Doctors divide neck lymph nodes into groups based on their position. Understanding the general layout helps if you’re trying to figure out what that lump is or where to check.
- Under the chin and jaw: A cluster sits directly beneath your chin, and another runs along the underside of your jawbone. These tend to react to infections in your mouth, teeth, or lips.
- Along the side of the neck: A long chain of nodes follows the large muscle that runs from behind your ear down to your collarbone (the sternocleidomastoid). Doctors split this chain into upper, middle, and lower groups. The upper nodes, just below the ear, are the ones most people notice first when they get a sore throat or ear infection.
- Back of the neck: Nodes in the posterior triangle sit between that same large muscle and the trapezius muscle at the back of your neck, extending down toward the collarbone.
- Front of the throat: A group of nodes sits around the windpipe and thyroid area, lower in the neck near the notch at the top of your breastbone.
Each group tends to drain lymph from a specific region. Swelling in a particular group often points toward the source of the problem. For example, nodes swollen just below one ear are more likely related to an ear or scalp infection on that side, while nodes swollen under the jaw often signal a dental or throat issue.
Why Neck Lymph Nodes Swell
The most common cause of swollen neck nodes is a viral infection, particularly the common cold, flu, or mononucleosis. Bacterial infections like strep throat, ear infections, infected teeth, and skin infections (such as cellulitis) also trigger swelling. Less common causes include cat-scratch disease, Lyme disease, chickenpox, shingles, and tuberculosis.
In most of these cases, the swelling is your immune system doing its job. The nodes enlarge because immune cells are multiplying rapidly inside them to fight off the infection. Once the infection clears, the swelling goes down, though it can take a few weeks to fully resolve.
Swollen lymph nodes can also result from autoimmune conditions, where the immune system mistakenly attacks the body’s own tissues, or from cancers. Lymphoma (cancer of the lymphatic system) and cancers that have spread from other sites, such as the throat, thyroid, or skin, can cause persistent node enlargement. This is far less common than infection, but it’s the reason persistent swelling deserves attention.
Normal Size vs. Something to Watch
Healthy lymph nodes in the neck are typically under 10 millimeters across, roughly the width of a pencil eraser. The exception is the upper group along the side of the neck (just below the ear), where nodes up to 15 millimeters can still be normal. In children and young adults, it’s common to feel small, movable nodes in the neck even when nothing is wrong.
Nodes that are enlarged from a routine infection are usually tender, somewhat soft, and movable under the skin. They tend to appear on both sides of the neck when the infection is systemic (like a cold) or on one side when the infection is local (like a single infected tooth). Nodes that are hard, fixed in place, painless, or growing steadily over several weeks are more concerning and worth having evaluated.
How to Check Your Own Neck Nodes
You can feel for lymph nodes using your fingertips in a gentle, circular motion. Start in front of your ears and work your way down: along the jawline, under the chin, down the sides of the neck, and finally into the hollows just above the collarbone. When checking the sides of your neck, tilt your head slightly toward the side you’re examining. This relaxes the muscle and makes it easier to feel underneath it. Always compare both sides, since asymmetry is more informative than size alone.
To check the nodes above your collarbone, hunch your shoulders forward and bring your elbows in. This loosens the skin in that area. Press gently into the hollow above the bone using a circular motion. Enlarged nodes here are less common with simple infections and more likely to prompt a medical workup if found.
How Swollen Nodes Are Evaluated
When swollen neck nodes persist or raise concern, the first step is usually an ultrasound. This imaging lets a doctor measure the node precisely and examine its internal structure. A node with a bright, uniform center on ultrasound is more likely benign. A node that appears dark in the center or has an uneven pattern is more suspicious. In one large study of over 500 neck nodes, nearly half of those with a dark or uneven internal pattern turned out to be malignant, compared to only 13% of nodes with a normal-looking center.
If the ultrasound findings are concerning, the next step is a needle biopsy, where a thin needle is inserted into the node (guided by ultrasound) to collect a small sample of cells. This is typically a quick, outpatient procedure. The sample is examined under a microscope to determine whether the cells are reactive (responding to infection), abnormal, or cancerous. In many cases, this biopsy provides a definitive answer without the need for surgery.
For the vast majority of people, swollen neck nodes are a temporary sign that the immune system is handling an infection. They shrink on their own as the underlying cause resolves. Nodes that remain enlarged, keep growing, or are accompanied by unexplained weight loss, night sweats, or fever lasting more than a couple of weeks warrant a closer look.