Retromolar triangle

The retromolar triangle, also known as the retromolar fossa, or retromolar space, or retromolar gap, is a triangular shaped depression located behind the third molar tooth in the lower jaw, or mandible, on each side. Its boundaries are defined as follows:

• On the lateral side, by the anterior sharp edge of the mandible's ramus, which continues with the oblique line,

• Medially by the temporal crest, starting from the apex of the coronoid process and descending along its medial aspect towards the third molar tooth,

• In front, by the back of the third molar tooth, or the second molar tooth if the wisdom tooth has not emerged.

The pterygomandibular raphe, which stretches from the hamulus of the medial pterygoid plate, is attached to the posterior aspect of mylohyoid line, close to the retromolar triangle.

The retromolar triangle serves as an important landmark for locating the correct site of injection for the inferior alveolar nerve block. The entry point for the needle is often slightly above the triangle, towards the pterygomandibular raphe, which is closely related to the triangle. Accurately identifying this area helps in directing the needle towards the mandibular foramen where the inferior alveolar nerve enters the mandible.