A patient presents with inability to open the jaw (trismus) and the pterygoid plate region is involved. Which muscle occupies the infratemporal fossa and closes the jaw?

• A Temporalis
• B Masseter
• C Lateral pterygoid
• D Medial pterygoid ✓

Explanation

The medial pterygoid muscle originates from the medial surface of the lateral pterygoid plate and inserts on the medial surface of the mandibular ramus. It is a powerful jaw-closer (elevator of the mandible) acting with the masseter and temporalis. In deep space neck infections or neoplasms involving the pterygomandibular space, medial pterygoid spasm causes trismus. The lateral pterygoid opens and protrudes the jaw.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.