Retromolar trigone

Last revised by Francis Deng on 8 Dec 2020

The retromolar trigone, sometimes called the retromolar fossa, is an oral cavity subsite that consists of the mucosa posterior to the last mandibular molar. It is roughly triangular shaped and extends superiorly towards the maxilla along the anterior surface of the mandible

Gross anatomy


The upper parts of the triangle attach the temporalis muscle 4. Specifically, the deeper fibers attach to the upper two-thirds of the medial border and the superficial fibers attach to the upper one-third of the lateral border 6.

Deep to the mucosa of the triangle is the pterygomandibular raphe 5.

Relations and/or boundaries

The borders of the retromolar trigone are as follows 4:

  • medially: temporal crest of the mandible (a ridge that runs along the anteromedial face of the coronoid process and ramus to which the temporalis muscle attaches)
  • laterally: anterior border of the ramus of the mandible
  • basally: posterior to the socket for the third molar

Related pathology

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