Adenoids, also known as proliferators and pharyngeal tonsils, are lobulated lymphoid tissues in the nasopharynx and can have five to six deep longitudinal grooves, in which debris and other secretions are sometimes seen. If the adenoids are large, they can fill up the nasopharynx and block the posterior nostril. The adenoids are hidden, so it is not easy for children to cooperate with the examination, and because the adenoids are located in the ear, nose and throat, adenoid diseases often occur together with other upper respiratory tract diseases and are easily overlooked. In 1868, Dr. Meyer of Denmark described in detail the separate tonsils of the nasopharynx – “adenoid proliferators” – and noted the large number of “lymphatic granules”, i.e., lymphocytes He noted a large accumulation of “lymphatic granules”, i.e. lymphocytes, into follicle-like material. This organ became known as the adenohypophysis, which in its plural form means that the gland resembles multiple proliferative ‘gland-likevegetations’. In 1884 Waldeye described the pharyngeal lymphatic ring, and the adenoids were an important part of the lymphatic ring of Waldeye. The adenoids are located at the intersection of the ear, nose and throat. Under normal physiological conditions, the proportion of adenoids relative to the bony structures of the pharyngeal cavity is greatest at 3-5 years of age, and the adenoids develop maximally at 6 or 7 years of age, and are also thought to be greatest at 10 years of age. The adenoids are the immune organs of the body, and their role is similar to that of the tonsils (palatine tonsils), but there are differences: 1. The embryonic origin of the tonsils and adenoids is not the same. The former may be derived from the Sessel’s bursa, while the latter is of unknown origin. 2. Their anatomical structures are different, with adenoids lacking an envelope. 3, The adenoids degenerate at about 14 years of age, whereas the tonsils degenerate at about 40 years of age. 4, Brook et al. concluded that the pathogenic microorganisms of tonsillar adenoids are different in normal and pathological conditions. 5, Weir et al. have reported a case of acute purulent adenoiditis, while acute purulent tonsillitis, which is clinically common. 6, Adenoids play an important role in OSA in children, while the role of tonsils in OSA in children is uncertain. 7. Adenoid tissue is an intermediate host for EBV virus transcriptional replication. Ear symptoms: Adenoid hypertrophy or lymphoid hyperplasia of the eustachian tube can cause obstruction of the pharyngeal orifice of the eustachian tube, resulting in secretory otitis media on that side, leading to hearing loss (conductive deafness) and tinnitus, and even suppurative otitis media. 2, nasal symptoms: hypertrophic adenoids and viscous secretions can block the posterior nostril, secretions in the nasal cavity is not easy to flow out, will be complicated by rhinitis, sinusitis, or aggravate the symptoms of its inflammation. The child often breathes with open mouth, speaks with an occlusive nasal sound, and snores during sleep. It is worth mentioning that prolonged nasal congestion and open-mouth breathing can cause abnormal facial development – adenoid face. For example, the upper jaw becomes longer, the hard palate is high arched, the upper incisors protrude, the bite is poor, the lips are thick, the upper lip is upturned, the lower lip hangs, the spirit is depressed, and the expression is dull. 3, pharynx, larynx and lower respiratory tract symptoms: secretions fill down and stimulate the respiratory tract mucosa, often causing paroxysmal cough, easily complicated by bronchitis, low fever, lymph nodes in the jaw angle can be enlarged. 4, systemic symptoms: mainly chronic toxicity and reflex neurological symptoms. Nasopharyngeal secretions are often swallowed by the affected children into the stomach, causing gastrointestinal activity disorders, resulting in anorexia, vomiting, indigestion, and subsequent malnutrition in children. Inadequate lung expansion due to poor breathing can lead to thoracic deformities. Poor breathing at night can leave children in a long-term hypoxic state and endocrine dysfunction, causing growth disorders. Parents can find children with inattention, night terrors, teeth grinding, bedwetting and other symptoms. In recent years, there is increasing evidence that adenoid hypertrophy plays an important role in the development of sleep apnea syndrome in children.