From the Guidelines
The oropharynx is the middle portion of the pharynx (throat) located behind the oral cavity, extending from the soft palate superiorly to the level of the hyoid bone inferiorly, and includes key structures such as the soft palate, uvula, palatine tonsils, base of the tongue, and posterior pharyngeal wall. In a typical anatomical diagram, these structures are visible and play a crucial role in the passageway of food and air, connecting the oral cavity to the laryngopharynx below 1. The oropharynx is also home to the rich lymphatic tissue known as Waldeyer's ring, which includes the palatine tonsils, lingual tonsils, and adenoids, and plays an important role in immune function by helping to filter pathogens that enter through the mouth and nose.
Key structures visible in an oropharynx diagram include:
- The soft palate and uvula at the top
- The palatine tonsils on both sides, which are framed by the palatoglossal and palatopharyngeal arches (anterior and posterior pillars)
- The base of the tongue anteriorly
- The posterior pharyngeal wall
- The lingual tonsils, located at the base of the tongue within the oropharyngeal space
Understanding the anatomy of the oropharynx is important for identifying conditions such as obstructive sleep apnea, oropharyngeal cancers, and infections such as tonsillitis or peritonsillar abscesses 2. The anatomic criteria for definitions of T4a and T4b for the oropharynx remain unchanged, but the words “resectable” (T4a) and “unresectable” (T4b) have been replaced by the terms “moderately advanced” (T4a) and “very advanced” (T4b) 3. However, the most recent study 1 provides the most up-to-date information on the anatomy of the oropharynx and its importance in head and neck cancer.
From the Research
Anatomy of the Oropharynx
The oropharynx is a complex structure that can be divided into several distinct components, including:
- The base of the tongue
- The soft palate
- The palatine tonsillar fossa
- The pharyngeal wall 4 These components are characterized by a unique anatomy, with the oropharyngeal mucosa being composed of a reticulated epithelium with a discontinuous basement membrane, also known as lymphoepithelium 4.
Layers of the Lateral Oropharyngeal Wall
The lateral oropharyngeal wall can be divided into three layers from medial to lateral, based on the styloid muscle diaphragm:
- The first layer, medial to styloid muscles, includes the tonsillar vascularization and the lingual branch of the glossopharyngeal nerve
- The second layer, lateral to constrictor muscles, includes the pharyngeal venous plexus, the glossopharyngeal nerve, and the lingual artery
- The third layer, lateral to styloid diaphragm, includes the parapharyngeal and submandibular spaces, the carotid vessels and lingual, vagus, glossopharyngeal and hypoglossal nerves 5
Neurovascular and Muscular Landmarks
The base of the tongue can be divided into central and lateral parts, which contain the lingual artery and lingual branches of the glossopharyngeal nerve 5. The main landmarks to find the neurovascular structures in each layer are described, and an anatomic division is proposed to help plan oropharynx and base of the tongue surgery 5.
Imaging of the Oropharynx
Imaging modalities such as CT and MRI can be used to visualize the oropharynx, with CT scans providing valuable information in the detection and staging of oropharyngeal malignancies 6. Ultrasound is also a promising imaging modality for evaluating the base of the tongue and the palatine tonsils, and is comparable and complementary to CT and MRI 7.