Oropharynx

The oropharynx (from the Latin pars oralis pharyngis) is the middle section of the pharynx, located posterior to the oral cavity. Superiorly, it is bounded by the soft palate, which separates it from the nasopharynx; inferiorly, it extends to the level of the epiglottis, where it continues into the laryngopharynx.

The oropharynx is a distinct structure, as it serves as the intersection of the respiratory and digestive tracts. Both inhaled air, directed toward the larynx, and the food bolus moving from the oral cavity into the esophagus pass through it.

Anatomy

Anteriorly, the oropharynx communicates with the oral cavity through the fauces, which are bounded by the palatoglossal arches. Laterally, within the tonsillar fossae between the anterior and posterior palatoglossal arches, the palatine tonsils are located. These are the largest accumulations of lymphoid tissue in the pharynx.

The oropharynx also comprises the root of the tongue and the lingual tonsil, the soft palate with the uvula, and the posterior pharyngeal wall. Along with the pharyngeal and tubal tonsils of the nasopharynx, the structures of the oropharynx form the pharyngeal lymphoid ring (Waldeyer’s ring), which is an essential part of human’s immunity. The mucosa of the oropharynx is lined with non-keratinized stratified squamous epithelium, resistant to mechanical stress exerted by food passage.

Clinical significance

The oropharynx is a common site for both inflammatory and neoplastic diseases. Examination of this region (pharyngoscopy) is a routine part of clinical evaluation by general practitioners and otolaryngologists.

Major pathologies of the oropharynx include:

• Acute pharyngitis: Inflammation of the mucosa, most often of viral origin.
• Acute tonsillitis: Acute inflammation of the palatine tonsils, usually caused by bacterial infection (most commonly group A β-hemolytic streptococcus).
• Chronic tonsillitis: Persistent chronic inflammation of the palatine tonsils, often accompanied by caseous plugs.
• Peritonsillar abscess: Purulent destruction of tissues surrounding the palatine tonsil. This is a serious complication of tonsillitis.
• Neoplasms: The most common malignant tumor is squamous cell carcinoma, strongly associated with smoking, alcohol consumption, and human papillomavirus (HPV) infection.

Differential Diagnosis

Sore throat is the leading symptom of oropharyngeal diseases. It is crucial to distinguish viral pharyngitis from bacterial tonsillitis, since the latter requires antibiotic therapy to prevent systemic complications such as rheumatic fever and glomerulonephritis. Clinical scoring systems, such as the McIsaac score, help estimate the likelihood of streptococcal infection. For instance, a peritonsillar abscess is associated with severe unilateral pain, asymmetry of the fauces, and difficulty opening the mouth (trismus). The condition requires urgent surgical drainage. Any persistent ulcerative lesion or induration in the oropharynx of an adult patient necessitates biopsy to exclude malignancy.