ヒト翼突筋静脈叢の形態学的研究

The purpose of the present investigation is to clarify the shapes of the human pterygoid plexus. For the purpose of this study, Fukuoka Dental College obtained 71 tissue blocks containing pterygoid plexus from 37 Japanese cadavers between the ages of 30-90years. The blocks were sectioned at 5mm by EXAKT [○!R]cutting system using a diamond band saw (200μm in thickness), and then were observed both macro and microscopically under a dissecting microscope. The tissue sections obtained from some tissue blocks were stained histologically and observed microscopically. Cranial blocks were also observed, using an MRI, and afterwards compared with those of living human specimens. The results were as follows. 1. The pterygoid plexus, which followed from an ovale plexus, was located inside the lateral pterygoid muscle from the top of the infratemporal fossa, to the bottom line of the middle lateral pterygoid muscle. 2. The constituent veins of the pterygoid plexus presented a sinus like structure with either thick or thin trabeculae. 3. The plexus parts and the sinus venosus parts of the pterygoid plexus were also confirmed by the MRI. 4. The constituent veins of the pterygoid plexus could be classified as type I, which presented a sinus like structure 3 mm in diameter, and type II, which presented a sinus like structure 3 mm and over. The frequency in appearance of both type I and II was 39.4% and 60.6% respectively. 5. In the constituent blood vessels of the pterygoid plexus, venous valve and artriovenous anastomoses, were observed. In conclusion, these findings suggest that the pterygoid plexus has a blood storable shape which easily causes a stagnant blood stream followed by a disturbance in the function of temporomandibular joints and the fatigue of masticatory muscle groups. This circulatory disturbance ultimatily appears to have an influence on the whole masticatory system.