To understand actions of the masticatory muscles, it is important to know their anatomical location and bony attachments in more depth. 

• The temporalis muscle fills the temporal fossa.
• The lateral and medial pterygoid muscles are situated in the infratemporal fossa.

Temporal fossa

Bones forming the borders of the temporal fossa are as follows:

• Medial wall - parts of the frontal, parietal, sphenoid and temporal bones;
• Upper border - superior temporal line (parietal bone);
• Lateral wall - zygomatic arch (formed by the zygomatic process of the temporal bone and the temporal process of the zygomatic bone).

Infratemporal fossa

Bony structures bordering the infratemporal fossa include the following:

• Greater wing and lateral plate of the pterygoid process of the sphenoid bone; 
• Posterior surface of the maxilla;
• Ramus of the mandible.