Lymph nodes of the head and neck: locations, node levels I to VI and Waldeyer's ring

Lymph nodes are small, bean-shaped organs spread along the lymphatic system. Each is surrounded by a tough capsule of connective tissue. Lymph enters a node through afferent lymphatic vessels and leaves through efferent vessels, and on the way the node removes debris and pathogens from the lymph. (OpenStax Anatomy and Physiology 2e, 21.1: Anatomy of the Lymphatic and Immune Systems.)

Nodes are found throughout the body but are concentrated in certain places: near the groin, armpits, neck, chest and abdomen. Their swelling during an infection is one sign of the close link between the lymphatic and immune systems. (OpenStax Anatomy and Physiology 2e, 21.1: Anatomy of the Lymphatic and Immune Systems.)

In everyday speech, enlarged neck nodes are often called "swollen glands", although they are lymph nodes, not glands. The American Academy of Family Physicians' review lists the head and neck node groups that can be felt as submental, submandibular, anterior and posterior cervical, pre-auricular and supraclavicular. (Gaddey HL, Riegel AM. Unexplained Lymphadenopathy: Evaluation and Differential Diagnosis. Am Fam Physician 2016.)

The head and neck nodes are grouped as superficial and deep. The superficial groups form a ring around the junction of the head and neck: occipital, mastoid (post-auricular), pre-auricular, parotid, submandibular and submental nodes, plus facial nodes on the cheek and superficial cervical nodes in the neck. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

The deep cervical nodes receive all the lymph of the head and neck, either directly or after it has passed through the superficial nodes. They form a vertical chain along the internal jugular vein inside the carotid sheath. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

TeachMeAnatomy lists the deep groups as prelaryngeal, pretracheal, paratracheal, retropharyngeal, infrahyoid, jugulodigastric (tonsillar), jugulo-omohyoid and supraclavicular nodes, divided into superior and inferior sets. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

Occipital nodes, usually one to three, lie at the back of the head near the lateral border of trapezius and drain the occipital scalp. Mastoid (post-auricular) nodes, usually two, lie behind the ear and drain the back of the neck, the upper ear and the back of the ear canal. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

Pre-auricular nodes, one to three in number, lie in front of the auricle and drain the superficial face and temple. Parotid nodes lie on the parotid gland, with a deeper set inside it; between them they drain the nose and nasal cavity, the external acoustic meatus, the middle ear and the lateral edge of the orbit, and the deep group also drains the nasopharynx. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

Facial nodes (infraorbital, buccinator and supramandibular) are scattered along the cheek and drain the lining of the nose and cheek, the eyelids and the conjunctiva. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

The submental nodes lie under the chin, superficial to the mylohyoid muscle, in the area often called the submental triangle. They drain the central part of the lower lip, the floor of the mouth and the tip of the tongue. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

The submandibular nodes, usually three to six, lie in the submandibular triangle under the body of the mandible. They drain the cheeks, the side of the nose, the upper lip, the outer parts of the lower lip, the gums and the front of the tongue, and they also receive lymph from the submental and facial nodes. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

In the level system, submental nodes are level Ia, lying between the anterior bellies of the two digastric muscles, and submandibular nodes are level Ib, behind and lateral to the anterior belly of digastric. (Radiopaedia: Cervical lymph node levels.)

The jugulodigastric node, one of the upper deep cervical nodes, is also called the tonsillar node. The palatine tonsils drain to it and to the other upper deep cervical nodes, so it is often enlarged in tonsillitis. (TeachMeAnatomy: The Tonsils and Adenoids (Waldeyer's Ring).)

Superficial cervical nodes lie along the anterior jugular vein, draining the front of the neck, and along the external jugular vein, draining the superficial side of the neck. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

The left supraclavicular node, known as Virchow's node, receives lymph from the abdominal cavity. Its enlargement (Troisier's sign) can be a sign that a stomach cancer has spread. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

Clinicians describe neck nodes by levels, which use landmarks that can be seen on scans and in surgery: the mandible, hyoid bone, cricoid cartilage, clavicle, sternocleidomastoid and trapezius. Radiopaedia notes that its scheme is a synthesis of radiologically useful boundaries and that definitions differ between specialties. (Radiopaedia: Cervical lymph node levels.)

Level I lies above the hyoid and below the mandible and mylohyoid (Ia submental, Ib submandibular). Levels II, III and IV follow the internal jugular chain under the sternocleidomastoid: level II from the skull base to the hyoid, level III from the hyoid to the cricoid cartilage, and level IV from the cricoid to the clavicle. (Radiopaedia: Cervical lymph node levels.)

Level V is the posterior triangle, between the back edge of the sternocleidomastoid and the front edge of the trapezius. It is split at the level of the cricoid into Va, which includes nodes along the spinal accessory nerve, and Vb, which includes the lateral supraclavicular nodes. Level IV includes the medial supraclavicular nodes, including Virchow's node. (Radiopaedia: Cervical lymph node levels.)

Level VI is the central compartment, from the hyoid to the suprasternal notch and between the two common carotid arteries. It contains the prelaryngeal (Delphian), pretracheal, paratracheal and perithyroid nodes. A level VII is used in different ways by different specialties and is not standardised. (Radiopaedia: Cervical lymph node levels.)

Waldeyer's ring is a ring of lymphoid tissue around the upper part of the pharynx. Its top is the pharyngeal tonsil in the roof of the nasopharynx; when enlarged, this is called the adenoids. On each side are the tubal tonsils around the openings of the Eustachian tubes and the palatine tonsils between the palatoglossal and palatopharyngeal arches. The lingual tonsil on the back third of the tongue completes the ring below. (TeachMeAnatomy: The Tonsils and Adenoids (Waldeyer's Ring).)

The tonsils are mucosa-associated lymphoid tissue (MALT) containing T cells, B cells and macrophages. They act as a first line of defence against pathogens entering through the nose and mouth. (TeachMeAnatomy: The Tonsils and Adenoids (Waldeyer's Ring).)

OpenStax describes tonsils as lymphoid nodules along the inner surface of the pharynx, with the pharyngeal tonsil at the back of the throat and the palatine tonsils on either side. (OpenStax Anatomy and Physiology 2e, 21.1: Anatomy of the Lymphatic and Immune Systems.)

Tonsillitis, inflammation of the palatine tonsils, is usually viral; bacteria cause about a third of cases. A peritonsillar abscess (quinsy) is a collection of pus beside the tonsil that needs drainage. (TeachMeAnatomy: The Tonsils and Adenoids (Waldeyer's Ring).)

Vessels leaving the deep cervical nodes join to form a jugular lymphatic trunk on each side. The left jugular trunk joins the thoracic duct at the root of the neck, which empties into the venous system at the left subclavian vein. The right jugular trunk joins the right lymphatic duct, which empties at the right subclavian vein. (TeachMeAnatomy: Lymphatic Drainage of the Head and Neck.)

The right lymphatic duct receives lymph only from the upper right side of the body; all other regions drain through the thoracic duct. (OpenStax Anatomy and Physiology 2e, 21.1: Anatomy of the Lymphatic and Immune Systems.)

Being able to feel a small lymph node is common. A family-medicine review notes that about half of otherwise healthy children have palpable lymph nodes at any one time, and that many healthy adults have inguinal (groin) nodes up to 2 cm across. (Gaddey HL, Riegel AM. Unexplained Lymphadenopathy: Evaluation and Differential Diagnosis. Am Fam Physician 2016.)

The same review defines lymphadenopathy as nodes that are abnormal in size, for example larger than 1 cm, or in consistency, while also noting that no particular size proves a node is malignant. Multiple small nodes that feel like shot pellets under the skin ("shotty" nodes) usually reflect a reaction to a viral infection. (Gaddey HL, Riegel AM. Unexplained Lymphadenopathy: Evaluation and Differential Diagnosis. Am Fam Physician 2016.)

Features that clinicians take more seriously include nodes that are hard, matted together or fixed to surrounding tissue, and nodes in certain places: palpable supraclavicular nodes are always considered abnormal. Tenderness alone is non-specific and may reflect inflammation from infection. This is educational information only; anyone worried about a lump should see a health professional. (Gaddey HL, Riegel AM. Unexplained Lymphadenopathy: Evaluation and Differential Diagnosis. Am Fam Physician 2016.)

The abdomen has its own large node groups. The pre-aortic nodes sit around the origins of the arteries to the gut and are divided into coeliac, superior mesenteric and inferior mesenteric groups. The superior and inferior mesenteric nodes collect lymph from mesenteric and colonic nodes and drain into the coeliac nodes, which give rise to the intestinal lymph trunks. (Kenhub: Lymph nodes of the thorax and abdomen.)

Together with the lateral aortic and retro-aortic nodes, the pre-aortic nodes make up the para-aortic lymph nodes. The lateral aortic group drains into the right and left lumbar lymph trunks, and lymph from the abdominal organs drains almost entirely through the thoracic duct. (Kenhub: Lymph nodes of the thorax and abdomen.)