The superior constrictor muscle forms the lateral border of the tonsillar fossa. The palatine tonsil is a lymphoid structure housed within the tonsillar fossa, which is bordered anteriorly and posteriorly by mucosal folds (commonly referred to as the anterior and posterior tonsil pillars) comprising the palatoglossus and palatopharyngeus muscles, respectively. 6, 7 As the palatine tonsils and pharyngeal tonsil are of greatest interest to the pediatric otolaryngologist in clinical practice, the remainder of this review will focus on these two components of Waldeyer's ring. Waldeyer's ring includes the following four structures: (1) the pharyngeal tonsil, located at the midline along the roof and posterior wall of the nasopharynx (2) the tubal tonsils (also known as Gerlach tonsils), located on either lateral nasopharyngeal wall immediately posterior to the Eustachian tube orifice and in close association with the torus tubarius (3) the palatine tonsils, located along each lateral oropharyngeal wall between the anterior and posterior tonsillar pillars (4) the lingual tonsils, located along the base of tongue and contiguous with the palatine tonsils at the glossotonsillar sulcus. 6 Positioned at the common entry of the respiratory and alimentary tracts, Waldeyer's ring plays a unique role in screening and filtering exogenous antigens, as well as in the initiation and maintenance of immune responses. Waldeyer's ring consists of non-contiguous mucosal-associated lymphoid tissues (MALT) arranged in a circumferential configuration in the nasopharynx and oropharynx. The purpose of this review is to describe the anatomy and physiology of Waldeyer's ring and how it pertains to surgical planning and subsequent patient management. 5 They are strategically located at the junction of the respiratory and digestive tracts to be able to serve as a site for continued lymphoid stimulation. Their primary function is to participate in the secondary immune system by immunologically sampling antigens and local pathogens. These entities are together a part of the mucosal immune system. The palatine tonsils, adenoids, tubal tonsils, and lingual tonsils are lymphoepithelial tissues that make up the components of Waldeyer's ring, named after the German anatomist Heinrich Wilhelm Gottfried von Waldeyer-Hartz. 4 An understanding of the anatomy and physiology of these mucosa-associated lymphoid tissues is paramount to understanding their diseased states as well as implications for surgical extirpation. Today, surveys indicate that complete excision via electrocautery is the preferred method for excision around the world thought many other techniques have been carried out successfully. By the 19th century, superior lighting, ability to control hemostasis, and anesthetic techniques made complete excision possible. 3 Over time, as popularity grew for the procedure, partial excision continued to be considered the safest and best method for excision. 2 Credit for the first complete tonsillectomy is given to Celsus in the 1st century AD. 1 Historically, tonsil surgery was limited to partial excision for fear of removing healthy tissue. Tonsillectomy and adenoidectomy are among the most common surgical procedures in the United States and around the world. Though routine procedures, the execution of tonsil and/or adenoid removal requires a thorough understanding of the anatomy of these lymphoepithelial organs so as to minimize the risk for rare serious complications that can occur. When medical management fails, tonsillectomy and/or adenoidectomy may be indicated for patient care. While the pathophysiology of these conditions is still incompletely understood, current evidence and future investigations may reveal patterns amenable to targeted medical management. Aberrant immune activation and/or regulation can lead to a myriad of pathologies, with adenotonsillar hypertrophy, chronic tonsillitis/adenoiditis, and recurrent otitis media among the most commonly encountered conditions by otolaryngologists. As part of the mucosal immune system, these structures function in exogenous antigen sampling and stimulation of immune responses. The pharyngeal and palatine tonsils are compact yet physiologically complex mucosa-associated lymphoid tissues that make up a portion of Waldeyer's ring.
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