On the arteria maxillaris which passes medial to the pterygoideus lateralis muscle of the Japanese--patterns of origin of the inferior alveolar, the masseteric and the posterior temporal arteries.

Variations in the patterns of origin of the inferior alveolar, the posterior deep temporal and the masseteric arteries when the maxillary artery passed medial to the pterygoideus lateralis muscle on 30 sides of 24 heads (10.8%) among a total of 278 sides of 139 heads of the Japanese, were investigated. The results obtained may be summarized as follows: 1. The maxillary artery gave off a common trunk between the inferior alveolar and the posterior deep temporal (76.7%), the latter distal to the former (16.7%) and in contact with their origins (6.7%). The masseteric artery always arose from the posterior deep temporal in 24 heads. 2. The above-mentioned common trunk was observed in 52.1% of males and 47.9% of females, as well as on 56.5% of left sides and 43.5% of right sides. 3. It can be said that the maxillary artery always passed medial to the pterygoideus lateralis, when the inferior alveolar arose in common with the posterior deep temporal.