The Smaller Occipital Nerve, Its Topographic Relation to the Trapezius-Sternocleidomastoideus Muscle System.

A Consideration on the Factors Determining the Course of a Nerve.

Abstract

The smaller occipital ner v e was studied in 100 body -sides of Japanese cadavers with special reference to its topographic relation to the neighboring muscles. The nerve perforated the trapezius in 19 body-sides and the sternocleidomastoid in 4. In 2 sides, it turned round an intermediate muscle bundle between the both muscles. In every of these anomalous cases was noticed a conspicuous bend of the nerve at the site where it pierced or passed round the muscle.
Mechanism of the occurrence of these conditions was dis c ussed. St ress was laid, thereby, on the conservative topological relationship between nerve and muscle, as well as on the invariable cutaneous territory of a nerve during development.
Description was also made on the N. occipitalis minor secundus and other accessory nerves.
Acknowledgement: A part of this study was made in the dissection rooms of the Tokyo Medical and Dental University and the Juntendo Medical School. Thanks are expressed to the Anatomy Departments of the schools for providing materials and facilities of investigation.