Where does the SUPERIOR head of the lateral pterygoid muscle insert?

Correct answer: D. Neck of the mandibular condyle and the articular disc/capsule

• A. The MEDIAL SURFACE OF THE RAMUS is the insertion of the MEDIAL PTERYGOID, which together with the masseter forms the pterygomasseteric sling.
• B. The CORONOID PROCESS is the insertion of the TEMPORALIS muscle.
• C. The ANGLE OF THE MANDIBLE is the insertion of the MASSETER on its lateral aspect and the medial pterygoid on its medial aspect.
• D. CORRECT. The SUPERIOR (upper) head arises from the infratemporal surface of the greater wing of the sphenoid and inserts primarily into the ARTICULAR DISC and CAPSULE, with some fibres onto the condylar neck (pterygoid fovea). It is active during CLOSING, stabilising the disc against the articular eminence as the condyle returns. The INFERIOR head arises from the lateral pterygoid plate and inserts on the pterygoid fovea of the condylar neck; it is active in OPENING and PROTRUSION.

Note: The superior head's disc attachment is the anatomical basis of ANTERIOR DISC DISPLACEMENT: hyperactivity or spasm of this head can pull the disc anteromedially, producing the reciprocal click of internal derangement — an opening click as the condyle recaptures the disc and a closing click as it slips off again.