QS Study

The palatine tonsil occupies the tonsillar fossa. They are a pair of soft tissue masses located at the rear of the throat (pharynx). One tonsil is located on the left side of the throat and the other is located on the right side.

Features –

  • The tonsil is almond shaped.
  • It has two surfaces medial and lateral.
  • Two borders anterior and posterior.

Gross anatomy

It is often described to have two borders, two poles and two surfaces:

  • anterior and posterior borders (described in relations below)
  • upper and lower poles: extending to the soft palate and dorsum of the tongue respectively
  • medial and lateral surfaces (described in relations below)

Two poles-upper and lower:

The medial surface is covered by stratified squamous epithelium continuous with that of the mouth. This surface contains 12-15 crypts.

The lateral surface is covered by a sheet of fascia which forms the capsule.

The bed of tonsil is formed by:

  1. The pharyngobasilar fascia.
  2. The superior constrictor and palatopharyngeus muscles.
  3. The buccopharyngeal fascia and 9th cranial nerve.

Boundaries of Palatine Tonsil 1

Fig: Boundaries of Palatine Tonsil

Boundaries and Relations

  • Superiorly: soft palate
  • inferiorly: dorsal surface of posterior 1/3 of the tongue
  • anteriorly: palatoglossal arch
  • posteriorly: palatopharyngeal arch
  • medially: covered by pharyngeal mucosa
  • laterally: tonsillar capsule (thickened pharyngeal submucosa), superior pharyngeal constrictor muscle.

Function

  1. They are the major defense against the oral and pharyngeal routes of infection.
  2. They contribute in the formation of T and B lymphocytes thus take part in the immunologic defense of the body.
  3. They keep the infection of the oral cavity localized.
  4. It also assists the body in trapping bacteria, thus allowing the body the time to manufacture antibodies and destroy invading germs.

Development: Each tonsil is developed from the central part of the second pharyngeal pouch.

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