eRadiograph Volume 7: Imaging of Oral Cavity | Page 22

From the posterior tonsillar wall spread may occur similar to the anterior wall spread
but more commonly to the posterior pharyngeal wall and pharyngoepiglottic fold to
reach the pyriform sinus. Lymphatic drainages is to level II and once it reaches the
posterior oropharyngeal wall drainage is to retropharyngeal nodes.
Tonsilar Fossa
Can spread along anterior/posterior tonsilar pillars.
From the tonsilar fossa it can spread lateral to parapharyngeal space and onto carotid
space, masticator space and into mandible.
Tonsilar fossa lesions have a higher incidence of nodal metastases 71 – 89%
contralateral in 22% nodes involved are level I – IV.
Posterior Pharyngeal Wall
These tumors are usually large at the time of diagnosis and can spread superiorly to the
nasopharynx, laterally into parapharyngeal space, inferiorly into hypopharynx,
anteriorly to tonsil and posteriorly into the prevertebral musculature.
Lymph node drainage is to the bilateral internal jugular nodes and retropharyngeal.
Base of Tongue/Lingual Tonsil
Anterior: Sublingual space, oral tongue, floor of mouth
Posterior: Anterior tonsillar pillar, palatine tonsils
Laterally: Medial ptyergoid, ptyergopalatine raphe, mandible

Inferior: Valleculae, pre epiglottic fat.
It is important to look for extension to pre epiglottic fat as this indicates a total glosso
aryngectomy. The pre epiglottic fat is a triangular shaped zone, anterior to epiglottis
and below hyoepiglottic ligament. This is best seen on sagittal images, an extension to
the lingual surface of epiglottis is indicative of a T3 lesion.
Nodal drainage is to level II to IV
70% of T1 at presentation have nodal disease
84% of T4 have nodal disease.

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Imaging of Oral Cavity

Superior: Tonsillar pillars