Investigations of the run and the attachment of the lateral pterygoid muscle in Japanese.

Studies of the run and the attachment of the lateral pterygoid muscle were made on 79 samples from 41 cadavers in the collection of the Department of Anatomy of the Tokyo Dental College. Origin shapes were classified into 3 types: type I, in which there is a clear boundary between the muscle venter adhesion for the upper muscle venter and the lower muscle venter; type II, where the boundary between them is unclear; and type III, where the difference between the two cannot be distinguished at all. When this classification was applied to the specimens, all 21 of the 1-venter specimens fell into type III; 37 (69.8%) of the 2-venter specimens fell into type I; 10 (18.9%) of the 2-venter specimens fell into type II, and 6 (11.3%) of the 2-venter specimens fell into type III. All 5 of the 3-venter specimens were type II. From the results of this studies, we saw that, regardless of which investigation method was employed, the number of venter runs and the origin configuration did not correlate at all.