Section 126. the Remainder of the Nerves Spring From the Hind-Brain.

The fourth pair supply the superior obliques, and the sixth the external recti; so that III., IV., and VI. are alike purely motor nerves, small and distributed, to the orbit. The fifth nerve, the trigeminal, is a much larger and more important one; it is a mixed nerve, having three main branches, of which the first two are chiefly sensory, the third almost entirely motor; it lies deeply in the orbit. V1 (see Sheet 9) runs up over the recti behind the eyeball, it is the ophthalmic branch; V2, the maxillary branch, runs deeply under the eyeball and emerges in front of the malar, and V3, the mandibular branch, runs down on the inner side of the jaw-bone to the jaw muscles and tongue.