lateral pterygoid muscle

A very simple guide for those who have to identify structures within the infratemporal fossa is as follows.

If you see muscles that are passing across the infratemporal fossa in a horizontal direction, they almost certainly will be the lateral pterygoid muscle.

If you see a muscle which has vertical fibres, then that's likely to be the medial pterygoid muscle.

A nerve passing into the mandibular foramen is the inferior alveolar nerve.

The muscle inserts into a little area called the pterygoid fossa just below the head of the mandible.

but it also inserts into the disc and into the capsule of the temporomandibular joint.

If the lateral pterygoid muscle on each side works together, then we can in fact protrude the jaw.

But its really important action is opening the jaw.