Lymph nodes are small, bean-shaped structures that are part of the body’s immune system. Found throughout the body, connected by lymphatic vessels, they filter substances in lymphatic fluid, playing a role in the body’s defense. Clusters are notable in the neck, armpits, and groin.
The Lymphatic System’s Purpose
The lymphatic system is a network of organs, vessels, and tissues that maintain fluid balance and support immune function. It collects excess fluid, called lymph, from tissues and returns it to the bloodstream, preventing swelling. This fluid contains proteins, minerals, fats, and waste products, including damaged cells and germs.
As part of the immune system, it protects the body from infection. Lymph nodes filter foreign particles like bacteria, viruses, and abnormal cells. They house lymphocytes, specialized white blood cells that identify and destroy invaders. When an infection is detected, these cells multiply.
Key Lymph Node Groups in the Neck
The neck contains numerous lymph nodes. Under the jawline and chin are the submandibular and submental nodes (Level I), which drain the oral cavity and parts of the mid-face.
Near the ears, pre-auricular nodes are in front, and post-auricular (mastoid) nodes are behind. At the back of the neck, occipital nodes drain the scalp and posterior neck.
Along the sides of the neck, parallel to the sternocleidomastoid muscle, are the superficial and deep cervical nodes. Deep cervical nodes subdivide into superior and inferior groups along the internal jugular vein (Levels II, III, and IV). These groups receive lymph from various head and neck structures.
Near the collarbone are the supraclavicular nodes, which receive lymph from deep lateral cervical vessels. All lymphatic vessels from the head and neck ultimately drain into the deep cervical lymph nodes, then empty into larger lymphatic trunks.
Understanding Swollen Lymph Nodes
Swollen lymph nodes, or lymphadenopathy, indicate the immune system is responding to an issue. This swelling often results from bacterial or viral infections like the common cold, strep throat, ear infections, or dental infections. Infected lymph nodes in the nearby area may become enlarged, tender, or painful.
Inflammatory conditions and allergies can also cause temporary swelling. This indicates immune cells are gathering to fight invaders or process waste. While often benign, certain characteristics warrant medical attention.
Consult a healthcare provider if swelling persists for more than a few days or weeks, or if nodes are larger than one centimeter. Other concerning signs include nodes that are hard, fixed, growing rapidly, or accompanied by unexplained weight loss, night sweats, persistent fever, or difficulty breathing. These symptoms can indicate more serious conditions, including certain cancers.