(1.36)

Now we'll move on, to look at the fifth cranial nerve, the trigeminal. It's the largest of the cranial nerves, and by far the most complex. It's named from the fact that it has three major branches, the ophthalmic, the maxillary and the mandibular. The main functions of the trigeminal nerve are to provide sensation to the face, the nasal cavity and the oral cavity, and to provide motor supply to the muscles of mastication.

As we saw in the last section, the trigeminal nerve emerges from the pons, and passes forwards. To follow it we'll go to an earlier stage of the dissection that we've been looking at. The trigeminal nerve passes forwards from the pons into a tunnel in the dura. The tunnel leads into a side cavity, the trigeminal cave, which we'll expose by removing the overlying dura.

Here's the trunk of the nerve. Here are its three branches: the ophthalmic, the maxillary, and the mandibular. All the sensory fibers of the trigeminal nerve synapse in this massive ganglion, the trigeminal ganglion. In relation to the dry bone, the trigeminal gangion is here.

The openings for the three branches are the superior orbital fissure for the ophthalmic, the foramen rotundum for the maxillary, and the foramen ovale for the mandibular.