Primo Vascular System in the Subarachnoid Space of a Mouse Brain

Figure 1

(a) Schematic illustration of the cranial view of a mouse brain. The sagittal sinus branches to two transverse sinuses at the confluence of sinuses where the λ point (arrow head) lies. The primo vessels ran along the sagittal sinus and branches and then along the two transverse sinuses (dotted line). The primo nodes were observed at the points designated as H and P on two sides of the brain. H is at the point where the hemisphere of the cerebellum and the vermis meet along the transverse sinus. P is further outside, along the transverse sinus near the end of the hemisphere of the cerebellum. The distances from the λ point to the H-point and the P-point were 3,763 μm and 5,967 μm, respectively. (b) Stereo microscopic image of the cranial view of a mouse brain. The symbols are the same as in (a). (c) Polarization microscope image of brain meninges complex of the dura and the pia mater peeled off from the brain and put on a slide with the pia mater side down. (d) Polarization microscope image of the same specimen rotated 45 degrees relative to (c). There appeared a strong polarization signal along the midline of the sagittal sinus. The polarization image was in agreement with those in the rabbit and the rat brains. The image shows a primo vessel in the falx cerebri under the dura mater of the superior sagittal sinus.