(Chapter 12) Footnote 26:

A confusing sentence: Vesalius’ use of his system for numbering the cranial nerves is inconsistent. Previously, his “lesser root” was described as a “facial motor” root of the third pair (trigeminal nerve), but here the reader is directed to letter H of figure 14, Book 7, which is probably the trochlear nerve (modern fourth cranial nerve). The trochlear nerve may be either the smaller root of Vesalius’ third pair, or along with the abducens nerve (modern sixth cranial nerve), the trochlear and oculomotor nerves compose Vesalius’ second pair. See Lind Epitome pp. 69-80; Singer 1952 p. 76; J.P. Shaw 1992. The 1555 edition revised the end of the sentence to read “ . . . which is distributed to the skin of the forehead and nearly all the face, the muscles that lie beneath, and in addition, to the nostrils and the muscles that raise the upper maxilla.”