Fig. 45. Scanning electron micrographs of human ciliary body vasculature after injection with methylmethacrylate. A. Anterior ciliary perforating artery (ACA) to intramuscular plexus (IMC), supplying the profuse capillary bed (CAP) of the anterior ciliary muscle. (X 54) B. Vasculature of a single ciliary process, supplied by anterior (AA) and posterior (PA) arterioles from the major arterial circle of the iris (MACI). The dilated marginal venules (MV) are clearly visible along the crest of the process and, along with a posterior venule, drain into three pars plana veins (PPVs). Many constricted segments seen in terminal arterioles to anterior and mid portion of the process. (X 96) C. Higher power view of constricted arterioles (arrows) to anterior edge of process. (X 300) (Courtesy of Dr. John Morrison)