The unique anatomy of the oral cavity and oropharynx are what allow us to chew our food and contribute to swallowing our food safely. Anteriorly there is the oral cavity, with a lot tissue types located in a small space. The posterior oral cavity is delineated from the oropharynx by an imaginary line from circumvallate papillae, anterior tonsillar pillars, and junction of the hard and soft palate.
The oral cavity contains the lips anteriorly and the vermillion border, the anterior two thirds of oral tongue, floor of mouth, the cheeks laterally, hard palate superiorly, superior, and inferior alveolar ridges, mylohyoid muscle inferiorly, anterior tonsillar pillar and retromolar trigone. Tumors and pathology can arise from any of the tissues in the oral cavity including the gingival, lingual and buccal mucosal linings, bone, teeth, muscles, nerves, blood vessels, and salivary glands.
The oropharynx is located behind the oral cavity and its most posterior margin is the posterior pharyngeal wall. The superior oropharynx margin is at the soft palate and ridge of musculature called (Passavant’s ridge), that opposes the soft palate, when elevation of the soft palate occurs. The oropharynx includes the soft palate and is located below the nasopharynx and is bordered below by the vallecula, located above the larynx and hypopharynx. The oropharynx contains the pharyngeal wall between the nasopharynx and pharyngoepiglottic fold, soft palate, tonsillar region and posterior one third tongue.
The lateral margins of the oropharynx contain the anterior tonsillar pillar formed by the Palatoglossus muscle, and posterior tonsillar pillar formed by the Palatopharyngeus muscle, in between these two tonsillar pillars is lymphoid tissue called the palatine or faucial tonsils. The tonsils are always an important site to always evaluate, as this is the most common site for squamous cell carcinoma, especially Human Papillomavirus (HPV) 16, that may go deep into the reticulated epithelium of the tonsil, the primary tumor in these cases may be small and the patients may present with enlarged neck nodes.
Magnetic Resonance Imaging of the Oral Cavity and Oropharynx.
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Advanced Magnetic Resonance Imaging of the Skull Base.
Kirsch CF, Ho ML.Semin Ultrasound CT MR. 2021 Jun;42(3):229-252. doi: 10.1053/j.sult.2021.04.006. Epub 2021 Apr 22.PMID: 34147160 Review.
Neuroimaging Characteristics of Nasopharyngeal Carcinoma in Children.
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ACR Appropriateness Criteria® Neck Mass-Adenopathy.
Expert Panel on Neurologic Imaging:; Aulino JM, Kirsch CFE, Burns J, Busse PM, Chakraborty S, Choudhri AF, Conley DB, Jones CU, Lee RK, Luttrull MD, Moritani T, Policeni B, Ryan ME, Shah LM, Sharma A, Shih RY, Subramaniam RM, Symko SC, Bykowski J.J Am Coll Radiol. 2019 May;16(5S):S150-S160. doi: 10.1016/j.jacr.2019.02.025.PMID: 31054741
Kaka AS, Kumar B, Kumar P, Wakely PE Jr, Kirsch CM, Old MO, Ozer E, Agrawal A, Carrau RE, Schuller DE, Siddiqui F, Teknos TN.Oral Surg Oral Med Oral Pathol Oral Radiol. 2013 Sep;116(3):327-35. doi: 10.1016/j.oooo.2013.04.011. Epub 2013 Jun 14.PMID: 23770280 Free PMC article.
Practical Tips for MR Imaging of Perineural Tumor Spread.
Kirsch CFE, Schmalfuss IM.Magn Reson Imaging Clin N Am. 2018 Feb;26(1):85-100. doi: 10.1016/j.mric.2017.08.006. Epub 2017 Oct 21.PMID: 29128008 Review.