Table 1 Insertion points and actions of the masticatory muscles

Lateral pterygoid

Greater wing of sphenoid (upper head) and lateral pterygoid plate (lower head).

Pterygoid fovea, temporomandibular joint, and articular disc.

Protrudes the mandible. The synergistic action of the bilateral lateral pterygoid muscles contributes to the opening of the mandible.

In condylar neck fractures, it pulls the condylar head anteriorly and medially.

Medial pterygoid

Lateral pterygoid plate, pyramidal process of palatine bone, and maxillary tuberosity.

Ramus and angle of the mandible.

Protrudes and elevate the mandible. The medial pterygoid, temporal, and masseter muscles close the mandible.

In mandibular angle fractures, it elevates the proximal bone fragment.

Temporal

Temporal fossa and temporal fascia.

Coronoid process and ramus of the mandible.

Retrudes and elevates the mandible. The medial pterygoid, temporal, and masseter muscles close the mandible.

In coronoid process fractures, it elevates and retracts the apical bone fragment.

Masseter

Zygomatic arch.

Coronoid process and ramus of the mandible.

Protrudes, retrudes, and elevates the mandible. The medial pterygoid, temporal, and masseter muscles close the mandible.

In horizontal branch or mandibular angle fractures, it elevates the distal bone fragment.