Vascular anatomy and hydrostatic pressure profile in the hamster cheek pouch

The purpose of this study was to describe the vascular architecture and blood supply to the hamster cheek pouch and to measure the intravascular pressure distribution in the entire pouch. Previous anatomic descriptions have focused either on the vasculature of the facial region or on the microcirculation of the cheek pouch tip. Micropressures in cheek pouch capillaries, terminal arterioles, and small venules have not previously been measured. Cheek pouches were prepared for examination under an intravital microscope using both everted and noneverted methods. Microvessel diameters were measured through a video system using a video micrometer, and intravascular hydrostatic pressures were measured with a servo null micropressure system. Blood vessels in the face and pouch were traced after injection of Microfil into the external maxillary artery. The results indicate that the pouch is supplied directly or indirectly by six small arteries in the neck and face. Fifty percent of the total pressure drop across the cheek pouch vasculature occurs in the small cheek pouch arteries, suggesting that these vessels are potentially important in controlling cheek pouch blood flow. The measurements of microvascular pressures and diameters in this study help clarify apparent discrepancies in similar measurements from previous studies.