Now we'll move on to look at the second and third divisions of the trigeminal, the maxillary and mandibular nerves. Before we look at these two nerves, which are both quite complex, we'll spend a minute reviewing the region into which they emerge. It's a little complex too. To see it, we'll first look at a dry skull in which the zygomatic arch has been removed.
Here's the area we'll be looking at. Here's the underside of the greater wing of the sphenoid bone, here's the lateral pterygoid plate, here's the back of the maxilla. This gap between the pterygoid process and the maxilla is the pterygo-maxillary fissure. It's continuous with this gap between the maxilla and the greater wing of the sphenoid, the inferior orbital fissure. Here's the inferior orbital fissure seen from in front.
The maxillary nerve emerges here, deep in the pterygo-maxillary fissure. The mandibular nerve emerges here, behind the lateral pterygoid plate.
To get to this remote area in a dissected specimen we have to remove several major structures: first the masseter muscle, then the deep temporal fascia, then the zygomatic arch, and then the temporalis muscle, and the ramus and coronoid process of the mandible, and finally this muscle, the lateral pterygoid, together with the condyle of the mandible.
This brings us into the infratempral fossa. Before we look at the nerves, let's get oriented. Heres the underside of the greater wing of the sphenoid, here's the lateral pterygoid plate, the back of the maxilla, the pterygo-maxillary fissure, and the inferior orbital fissure.
This is the medial pterygoid muscle. It slopes downwards and outwards towards its insertion on the medial aspect of the mandible. This muscle is the buccinator.