Abstract
For the morphological classification of the muscles of mastication in man, and especially in order to understand the positional significance of the pterygolds in these muscles of mastication, the nerves of supply were examined minutely in five head-halves.
1. The nerves of supply of the masticatory muscles are classified into three categories depending upon the position of origin from the mandibular nerve.
(1) proximal nerves: the masseteric nerve, and the posterior and middle deep temporal nerves;
(2) intermediate nerves: the anterior deep temporal nerve, and the nerves to the lateral pterygoid, which are usually in a common trunk with the buccal nerve; and
(3) distal nerve: the nerve to the medial pterygoid.
While the nerve to the medial pterygoid arises from the medial surface of the mandibular nerve in close proximity to the otic ganglion, the other nerves tend to originate from the lateral surface. According to these differences, it would appear appropriate to classify the lateral pterygoid together with the masseter and temporalis as the lateral muscles of mastication, and only the medial pterygoid as the medial muscle of mastication.
2. The medial pterygoid is divided into anterior and posterior portions, but the laminate composition is not so distinct. The nerve of supply is divided into the medial, intermediate, lateral and posterior main branches.
3. The nerves of supply to the lateral pterygoid arise from the angle between the buccal and mandibular nerves and from the buccal nerve. Generally, the upper head nerves and lower head nerves originate separately. The more proximally a nerve arises, the more medially it tends to be distributed. Sometimes the lower head nerves wind upwards to enter the upper head as recurrent branches.
