The lymphatic system is of key importance in the body, as it serves to drain tissue fluid, plasma proteins and other cellular debris back into the bloodstream. It is also important in the body's defence by acting as a filtration system to protect against infection. Lymph nodes play a key role in this process, filtering and directing the lymph fluid into the venous system before it is circulated throughout the body. This article will explore the anatomy of lymphatic drainage throughout the head and neck, and how this is relevant clinically. We will also look at Waldeyer's ring, the collection of lymphatic tissue surrounding the superior pharynx.
The lymphatic vessels in the head and neck can be divided into two main groups: superficial vessels and deep vessels.
The superficial vessels are responsible for draining lymph from the scalp, face and neck into the superficial ring of lymph nodes located at the junction of the head and neck.
The deep lymphatic vessels of the head and neck originate from the deep cervical lymph nodes, which converge to form the left and right jugular lymphatic trunks.
There are two distinct groups of lymph nodes in the head and neck. The first is a superficial ring of lymph nodes, and the second is a vertical group of deep lymph nodes.
The superficial lymph nodes of the head and neck receive lymph from the scalp, face and neck. They are arranged in a ring shape, extending from underneath the chin, to the posterior aspect of the head. They ultimately drain into the deep lymph nodes.
These superficial lymph nodes are important for draining lymph from the head and neck. They form part of Waldeyer's ring, the collection of lymphatic tissue which surrounds the superior pharynx. The lymph nodes of the Waldeyer's ring have a major role to play in immunity, as they form part of the body's primary defence against infection.
As well as acting as a filtration system, the lymphatic system is also responsible for maintaining fluid balance in the body. It is crucial for the body to maintain this balance, otherwise it could be detrimental to the body's functioning. The lymph nodes of the head and neck are therefore of huge importance, as they are responsible for collecting and filtering lymph fluid before it is returned to the bloodstream.
From this article, it is clear to see that the lymphatic system of the head and neck play a major role in the body's immunity, fluid balance and overall health. It is also important to be aware of the anatomy of the lymphatic system, as this can be beneficial when diagnosing and treating medical conditions.
The lymphatic vessels of the head and neck can be divided into two major groups; superficial vessels and deep vessels. The deep lymphatic vessels arise from the deep cervical lymph nodes, and converge to form the left and right jugular lymphatic trunks. The left jugular combines with the thoracic duct at the root of the neck, and the right jugular forms the right lymphatic duct at the root of the neck. The lymph nodes of the head and neck are divided into a a superficial ring of lymph nodes, and a vertical group of deep lymph nodes.
The superficial vessels drain lymph from the scalp, face and neck into the superficial ring of lymph nodes at the junction of the neck and head. The anterior nodes lie close to the anterior jugular vein and collect lymph from the superficial surfaces of the anterior neck. The posterior lateral nodes sit close to the external jugular vein and collect lymph from superficial surfaces of the neck.
The deep (cervical) lymph nodes receive all of the lymph from the head and neck – either directly or indirectly via the superficial lymph nodes. They are organised into a vertical chain, located within close proximity to the internal jugular vein within the carotid sheath. The efferent vessels from the deep cervical lymph nodes converge to form the jugular lymphatic trunks. The nodes can be divided into superior and inferior deep cervical lymph nodes, and some of these include the prelaryngeal, pretracheal, paratracheal, retropharyngeal, infrahyoid, jugulodigastric (tonsilar), jugulo-omohyoid and supraclavicular nodes.
Virchow’s node is a supraclavicular node located in the left supraclavicular fossa, which is immediately superior to the clavicle and receives lymph drainage from the abdominal cavity. The finding of an enlarged Virchow’s node is referred to as Troisier’s sign, and indicates the presence of cancer in the abdomen, specifically gastric cancer, that has spread through the lymph vessels.
Waldeyer’s tonsillar ring refers to the collection of lymphatic tissue surrounding the superior pharynx. This lymphatic tissue responds to pathogens that may be ingested or inhaled. The tonsils that make up the ring are as follows:
The palatine tonsils can become inflamed due to a viral or bacterial infection. In such a case, they appear red and enlarged, and are accompanied by enlarged jugulo-digastric lymph nodes. Chronic infection of the palatine tonsils can be treated with their removal, a tonsillectomy. When performing a tonsillectomy, there may be bleeding primarily from the external palatine vein and secondarily from the tonsilar branch of the facial artery.
If an infection spreads to the peritonsillar tissue, it can cause abscess formation. This can cause deviation of the uvula, known as quinsy. A quinsy is a medical emergency, as it can potentially cause obstruction of the pharynx. It is treated with draining of the abscess and antibiotics.
The lymphatic system of the head and neck drains lymph from the face, scalp, and neck. This includes lymph from the submandibular nodes, facial nodes, superficial cervical lymph nodes, and deep (cervical) lymph nodes.
The submandibular nodes are usually located between 3 and 6 in number. They drain lymph from the floor of the mouth and lower lip.
The facial nodes are also known as the maxillary/infraorbital, buccinator, and supramandibular lymph nodes. These nodes drain lymph from the facial regions, including the cheeks, eyelids, and forehead.
The superficial cervical lymph nodes are located on either side of the neck. They can be divided into superficial anterior and posterior cervical nodes. These nodes receive lymph from the scalp, face, and anterior neck.
The deep cervical lymph nodes are situated along the carotid sheath, near the internal jugular vein. The deep cervical lymph nodes receive lymph from the head and neck either directly or indirectly through the superficial lymph nodes. All of these deep cervical lymph nodes ultimately converge into the jugular lymphatic trunks. The main deep cervical lymph nodes are the prelaryngeal, pretracheal, paratracheal, retropharyngeal, infrahyoid, jugulodigastric (tonsilar), jugulo-omohyoid, and supraclavicular nodes.
Waldeyer’s tonsillar ring is a collection of lymphatic tissue situated around the superior part of the pharynx. Its primary purpose is to filter pathogens that are ingested or breathed in. The tonsil ring is composed of four tonsils, as follows:
The palatine tonsils can become inflamed due to a viral or bacterial infection. The infected tonsil is enlarged in size, appears red, and is accompanied by enlarged jugulo-digastric lymph nodes. If the infection persists, the palatine tonsils may need to be removed through a tonsillectomy.
During a tonsillectomy, there is typically bleeding from the external palatine vein and the tonsilar branch of the facial artery. If the infection spreads to the peritonsillar tissue, it can cause abscess formation, known as quinsy. This is a medical emergency as it can block the pharynx. Treatment requires draining the abscess and antibiotics.
Until 2015, it was believed that the brain lacked lymphatic vessels. It was only then that scientists discovered these vessels in the brains of both mice and humans. Currently, research is being conducted to determine and describe the lymphatic vessels connected to the brain.
