Root of tongue

Last revised by Francis Deng on 22 Jan 2023

The root of tongue is the deeper anatomical part of the tongue contained in the oral cavity

The term root of tongue should not be confused with the base of tongue, which is part of the oropharynx and is the posterior third of the tongue, posterior to the circumvallate papillae. 

Terminology pertaining to the tongue can be confusing with terms such as mobile tongue, base of tongue, root of tongue, and floor of mouth being used in different ways 1,2. Here is a glossary of terms, along with which space it belongs to.

The root of tongue includes the lingual septum and bilateral genioglossus and geniohyoid muscles (genioglossus-geniohyoid muscle complex) 1,2.

  • anterior border: mandible

  • lateral borders: sublingual space

  • inferior border: U-shaped mylohyoid muscle under the geniohyoid muscles, the floor of mouth

  • posterior border: base of tongue

Of note, squamous cell carcinoma does not originate from the root of tongue itself, but rather invades it from adjacent mucosal surfaces of the oral cavity or anterior oropharynx. This is important in staging for oral cavity or oropharyngeal squamous cell carcinoma 3.

These are multiple entities that may arise from the root of tongue 1.

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