The pharyngeal plexus contains fibers of cranial nerves IX, X, and XI. The nervous supply to the adenoids is via the pharyngeal plexus. The lymphatic drainage of the adenoids is through the pharyngomaxillary space lymph nodes and the retropharyngeal lymph nodes. The pharyngeal plexus and the pterygoid plexus communicate, eventually draining into the facial veins and internal jugular veins. The venous drainage of the adenoids is through the pharyngeal plexus. The arterial supply of the adenoids is from the basisphenoid artery, the ascending pharyngeal artery, the ascending palatine artery, the pharyngeal branch of the maxillary artery, the tonsillar branch of the facial artery, and the artery of the pterygoid canal. Dysfunctional facial evolution may cause craniofacial deformities such as cleft palate and cleft lip. The fusion of two lateral primordia forms the adenoids during embryological development. The human face develops as part of the viscerocranium throughout the fourth to tenth weeks of fetal life. The prenatal development of the head during embryogenesis consists of the neurocranium and the viscerocranium. The adenoids can function as a bacterial reservoir for the nasal cavity and are implicated in the pathogenesis of chronic rhinosinusitis. Through this mechanism, the adenoids aid in the development of immunologic memory throughout childhood. Recent scientific literature has provided some evidence that adenoids also produce T lymphocytes (cellular immunity) like the thymus gland. Activation of B cells leads their proliferation in areas called germinal centers this helps in producing IgA immunoglobulins. On the surface, adenoid tissue has specialized antigen-capture cells (ACC), M cells, which uptake the pathogenic antigens and then alert the underlying B cells. Adenoids, in conjunction with the lingual and palatine tonsils, are involved in the development of T cells and B cells. Histologically, the lymphoid tissue of the adenoids divides into four lobes with seromucous glands interposed throughout the substance of the tissue.Īs a portion of the Waldeyer ring, adenoids compose the lymphoid tissue that serves as a defense against potential pathogens in the pharynx. Their composition is of respiratory epithelium. Structure and FunctionĪdenoids are pyramidal in shape, with the apex of the pyramid directed towards the nasal septum, and the base of the pyramid present between the roof and the posterior wall of the nasopharynx. Adenoids with other lymphatic tissue in the nasopharynx are the first line of defense against ingested or inhaled pathogens. These lymphoid masses have an important immunologic function, and hypertrophy can pose a risk for disease pathologies in children. The fossa of Rosenmuller is on the lateral wall of the nasopharynx, just behind the cartilage of the eustachian tube. Adenoid tissue can be found extending to the eustachian tube opening and the fossa of Rosenmuller. They are present from the seventh month of gestation and typically grow until age 5. They form part of the Waldeyer ring, whose components include the adenoids, the palatine tonsils, and the lingual tonsils. The adenoids are midline structures situated on the roof and posterior wall of the nasopharynx. Meyer first described this mucosa-associated lymphoid tissue in 1868. The adenoids exist as a rectangular mass of lymphatic tissue in the nasopharynx.
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