Structure
The head and neck lymph nodes are arranged as a superficial ring around the base of the head and a deep vertical chain in the neck. Lymph generally passes through one or more ring or regional nodes before reaching the deep chain.
The pericervical ring
A collar of superficial node groups lies where the head meets the neck:
- Occipital nodes at the apex of the posterior triangle drain the back of the scalp.
- Mastoid (retroauricular) nodes behind the ear drain the posterior scalp and back of the ear.
- Parotid (preauricular) nodes, on and within the parotid gland, drain the forehead, temple, eyelids, external ear and parotid.
- Submandibular nodes beside the submandibular gland drain most of the face, the nose, upper lip, lateral lower lip, gums and anterior tongue.
- Submental nodes below the chin drain the central lower lip, floor of the mouth and tip of the tongue.
Buccal, lingual and retropharyngeal nodes are small outlying groups. Superficial cervical nodes along the external jugular vein receive from the parotid and mastoid groups.
The deep cervical chain
The deep cervical nodes lie along the internal jugular vein, mostly under sternocleidomastoid. They receive lymph directly from the pharynx, larynx, thyroid and deep structures, and indirectly from all the superficial groups. Two named nodes are clinically important: the jugulodigastric node, just below the posterior belly of digastric, and the jugulo-omohyoid node, just above the omohyoid tendon. A smaller anterior group includes the prelaryngeal, pretracheal and paratracheal nodes.
Neck levels
Clinicians describe cervical nodes by level, a system that maps the deep chain onto surface and imaging landmarks for cancer staging and surgery.
| Level | Name | Boundaries |
|---|---|---|
| I | Submental (Ia) and submandibular (Ib) | Ia between the anterior bellies of digastric and the hyoid; Ib between the bellies of digastric and the mandible |
| II | Upper jugular | Skull base to the hyoid; split into IIa and IIb by the accessory nerve |
| III | Middle jugular | Hyoid to the lower border of the cricoid cartilage |
| IV | Lower jugular | Cricoid to the clavicle |
| V | Posterior triangle | Behind sternocleidomastoid, in front of trapezius, above the clavicle |
| VI | Central (anterior) compartment | Hyoid to the suprasternal notch, between the carotid arteries |
Levels II to IV lie along the internal jugular vein, deep to sternocleidomastoid. Level VI contains the prelaryngeal (Delphian), pretracheal and paratracheal nodes around the thyroid and larynx.
Drainage of key sites
The drainage pattern of a primary site predicts where its cancer spreads first.
- Tongue: the tip drains to submental nodes, the lateral anterior two-thirds to submandibular and then deep nodes, and the central part to deep nodes on both sides. The posterior third drains to the jugulodigastric nodes bilaterally. Lymph from the tongue often reaches the jugulo-omohyoid node directly.
- Palatine tonsil: the jugulodigastric node, often called the tonsillar node, which enlarges with tonsillitis.
- Larynx: above the vocal folds to upper deep nodes with the superior laryngeal vessels; below the folds to prelaryngeal, pretracheal and paratracheal nodes and then lower deep nodes. The vocal folds have very few lymphatics, so early glottic cancer rarely spreads to nodes.
- Thyroid: central compartment nodes (level VI) and the lateral deep chain.
- Nasopharynx: retropharyngeal nodes and the upper deep and posterior triangle nodes.
- Lips: upper lip and lateral lower lip to submandibular nodes; the central lower lip to submental nodes.
Termination
Efferent vessels from the lowest deep cervical nodes form the jugular lymphatic trunk on each side. On the left it usually joins the thoracic duct, which arches up to about the level of C7 before descending to enter the junction of the left internal jugular and subclavian veins. On the right it joins the right lymphatic duct or enters the venous junction directly. The subclavian and bronchomediastinal trunks may join the same point or open separately.
Nodes in the left supraclavicular fossa lie near the termination of the thoracic duct and can receive spread from abdominal and thoracic cancers.
Clinical relevance
A neck lump is examined by level, and its position suggests the primary site. A hard node in level II points to the oropharynx or tongue base; a level VI node to the thyroid or larynx; a level V node to the nasopharynx or skin of the scalp. An enlarged left supraclavicular node (Virchow node, Troisier sign) raises the possibility of gastric or other abdominal cancer.
Neck dissection removes the nodal levels at risk:
- Radical neck dissection removes levels I to V with sternocleidomastoid, the internal jugular vein and the accessory nerve.
- Modified radical neck dissection removes the same levels but preserves one or more of these three structures.
- Selective neck dissection removes only the levels most at risk for the primary site.
Sacrificing the accessory nerve causes shoulder drop and pain. Injury to the thoracic duct during left-sided level IV dissection causes a chyle leak.