The Palatine Tonsil

The Palatine Tonsil

The palatine tonsil represents the largest accumulation of lymphoid tissue in the head and neck region. Each tonsil has a compact body with a definite thin capsule on its deep surface. A stratified squamous epithelium lines the outer surface of the tonsil and invaginates deeply into the lymphoid tissue to form multiple crypts. demonstrates normal tonsils. The tonsillar fossa is composed of three muscles:

the palatoglossal muscle, the palatopharyngeal muscle, and the superior constrictor muscle. The palatoglossal muscle forms the anterior pillar and the palatopharyngeal muscle forms the posterior pillar. The tonsillar bed is formed by the superior constrictor muscle of the pharynx. The arterial blood supply of the tonsil enters primarily at the lower pole and is derived from the tonsillar branch of the dorsal lingual artery, the ascending palatine artery and the tonsillar branch of the facial artery. The ascending pharyngeal artery and the lesser palatine artery also contribute to the

vascular supply at the upper pole. Venous blood drains through the peri tonsillar plexus around the capsule. The plexus then drains into the lingual and pharyngeal veins, which in turn drain into the internal jugular vein.

The nerve supply of the tonsillar region is through the tonsillar branches of the glossopharyngeal nerve and the descending branches of the lesser palatine nerves. The cause of referred otalgia with tonsillitis is through the tympanic branch of the glossopharyngeal nerve. The lymphatic drainage courses through the upper deep cervical lymph nodes.

Microbiology of Tonsils:

Many organisms can induce inflammation of the tonsils. These include bacteria, viruses, yeasts, and parasites. Several pathogens and their clinical hallmarks are summarised in Table 1. Some of the infectious organisms are part of the normal oropharyngeal flora whereas others are external pathogens. Because the oropharynx is colonised by many organisms, most infections are polymicrobial. These organisms work synergistically and can be demonstrated in mixed aerobic and

anaerobic infections.

Group A Streptococcus is the most common bacterial cause of acute pharyngitis. This pathogen has importance from a public health standpoint in that it is a potential precursor to two serious sequelae: acute rheumatic fever and post-streptococcal glomerulonephritis. For this reason, most authorities recommend that the diagnosis of Group a Haemolytic Streptococcal Pharyngitis be verified by microbiology tests (swabbing) in patients who appear, based on clinical and epidemiological evidence, to have this illness. A full course of antibiotic therapy is recommended in these patients.