The lymphatic system is a network of vessels and nodes that filter and transport lymphatic fluid throughout the body. The lymph nodes of the head and neck play a critical role in the immune response to infections and diseases in the region. In this article, we will discuss the anatomy of the lymph nodes in the head and neck, their function, and their importance in clinical medicine.
Location of the Lymph Nodes in the Head and Neck
There are approximately 400-450 lymph nodes in the human body, with about 60-70 nodes located in the head and neck region. All the lymph from the head and neck drains directly or indirectly into a vertical chain of deep cervical lymph nodes. These nodes surround the internal jugular vein or carotid sheath and extend from the base of the skull to the root of the neck.
Organization of the Lymph Nodes in the Head and Neck
Most of the lymphatic fluid reaches the deep cervical nodes after being filtered through the outlying lymph nodes, which are arranged in outer and inner circles.
1. The Outer Circle of Lymph Nodes
The outer circle forms a “pericervical collar” at the junction of the head and neck. It consists of lymph nodes extending from the chin to the occiput. The outer circle includes submental, submandibular, buccal, parotid, retroauricular, and occipital nodes, as well as superficial cervical and anterior cervical nodes.
2. The Inner Circle of Lymph Nodes
The inner circle surrounds the upper part of the respiratory and alimentary passages, and includes pretracheal, paratracheal, and retropharyngeal nodes. Deep to the inner circle, a submucosal ring of lymphoid tissue known as Waldeyer’s ring surrounds the commencement of the air and food passages.
Waldeyer’s ring includes the nasopharyngeal tonsil above and behind, the tubal and palatine tonsils at the sides, and the lingual tonsils below and in front. The Waldeyer’s ring prevents the invasion of exogenous antigens, including micro-organisms from the exterior, and also filters tissue fluid, which is collected by the lymph nodes of the inner circle.
| Location | Node Group | Afferents | Efferents |
|---|---|---|---|
| Submental | Outer circle | Tip of tongue | Submandibular and Jugulo- |
| Floor of the mouth | omohyoid nodes | ||
| Lingual and labial gums | |||
| Central part of lower lip | |||
| Submandibular | Outer circle, Inner circle | Forehead | Jugulo-omohyoid nodes |
| Medial angle of eye | |||
| Side of the nose | |||
| Cheek and angle of mouth | |||
| Whole of upper lip | |||
| Lateral part of lower lip | |||
| Anterior two-thirds of | |||
| the tongue | |||
| Upper gum through the | |||
| infra-orbital foramen | |||
| Lower gum through the | |||
| mental foramen | |||
| Frontal, maxillary and | |||
| most of ethmoidal sinuses | |||
| Jugulo-digastric | Deep cervical, Inner circle | Palatine tonsils | Lower group of deep cervical |
| Posterior one-third of | nodes | ||
| the tongue | |||
| Jugulo-omohyoid | Deep cervical, Inner circle | Tongue | Descending jugular lymph trunks |
| Upper deep cervical | Inner circle | Pharynx | Lower deep cervical nodes |
| Larynx | |||
| Lower deep cervical | Inner circle | Trachea | Descending jugular lymph trunks |
| Esophagus | |||
| Thyroid gland | |||
| Thoracic wall | |||
| Upper limb |
Deep Cervical Lymph Nodes
All the lymph from the head and neck drains into a vertical chain of deep cervical lymph nodes, which are located along and around the internal jugular vein. The deep cervical nodes are further divided into upper and lower groups, which are separated by the intermediate tendon of omohyoid or the bifurcation of the common carotid artery.
The Jugulo-digastric Group
Some of the nodes in the upper group of deep cervical nodes, known as the jugulo-digastric nodes, are situated below the posterior belly of the digastric in a triangular area bounded by the posterior belly of the digastric, facial vein, and internal jugular vein. These nodes receive afferents primarily from the palatine tonsils and the posterior one-third of the tongue, and its efferents drain into the lower group of deep cervical nodes.
The Jugulo-omohyoid Group
Amongst the lower group, the jugulo-omohyoid nodes lie on the internal jugular vein just above the intermediate tendon of omohyoid. They receive afferents directly from the tongue and indirectly through the submental, submandibular, and upper deep cervical nodes. The jugulo-omohyoid nodes form the principal lymph nodes of the tongue. Some members of the lower deep cervical nodes extend along the brachial plexus and subclavian.
Parotid nodes
These are situated on the surface of parotid gland, and are divided into pre-auricular and post-auricular groups by the facial nerve. They receive lymph from the temple, forehead, lateral part of eyelids and conjunctiva, auricle, external acoustic meatus and adjacent skin, cheek, lateral part of the nose and upper lip. They also receive lymph from the upper part of deep cervical nodes.
Occipital nodes
These are two or three in number, situated at the back of the neck in the subcutaneous tissue overlying the insertion of the trapezius. They receive lymph from the back of the scalp as far as the vertex, and also from the skin of the upper part of neck.
Summary of Lymph Nodes in the Head and Neck Region
| Lymph Node Group | Location | Afferents | Efferents |
|---|---|---|---|
| Inner circle | Surrounding the upper part of respiratory and alimentary passages | Waldeyer’s ring, Inner Circle | Deep cervical lymph nodes |
| Waldeyer’s ring | Surrounding the commencement of the air and food passages | Exogenous antigens, tissue fluid | Inner Circle |
| Deep cervical lymph nodes | Along and around the internal jugular vein | Outlying lymph nodes of inner and outer circles | Descending jugular lymph trunks |
| Outer circle | From the chin to the occiput | Submental, submandibular, buccal, parotid retroauricular and occipital nodes | Superficial cervical and anterior cervical nodes |
| Submental nodes | Between the anterior bellies of both digastrics | Wedge-shaped block of tissue which includes the tip of tongue, floor of the mouth, lingual and labial gums opposite the lower incisor teeth, and central part of lower lip | Submandibular and jugulo-omohyoid nodes |
| Submandibular nodes | In the digastric triangle beneath the deep cervical fascia, in actual contact with the submandibular salivary gland | An extensive wedge-shaped area including the centre of the forehead, medial angle of eye, side of the nose, cheek and angle of the mouth, whole of the upper lip, lateral part of lower lip, anterior two-thirds of the tongue, upper gum through the infra-orbital foramen, and lower gum through the mental foramen, frontal, maxillary and most of the ethmoidal sinuses | Upper deep cervical lymph nodes |
| Parotid nodes | On the surface of the parotid gland | The temple, forehead, lateral part of eyelids and conjunctiva, auricle, external acoustic meatus and adjacent skin, cheek, lateral part of the nose and upper lip | Upper deep cervical lymph nodes |
| Occipital nodes | At the back of the neck in the subcutaneous tissue overlying the insertion of the trapezius | Back of the scalp as far as the vertex, and also from the skin of the upper part of neck | Superficial cervical and posterior auricular lymph nodes |
Conclusion
The lymphatic system plays an important role in maintaining immune function and fighting infection in the body. In the head and neck region, lymph nodes are located in both inner and outer circles, with the inner circle surrounding the upper part of the respiratory and alimentary passages and including Waldeyer’s ring. The outer circle includes lymph nodes from the chin to the occiput.
Each group of lymph nodes receives afferents from specific areas and drains into specific efferent nodes. Understanding the location and drainage patterns of lymph nodes in the head and neck region can aid in the diagnosis and treatment of various conditions, including