Spine, vertebral venous plexus, cranial sinuses, shown in situ, in 3 numbered illustrations. 1 illustration of spine divided in coronal section, vertebral bodies removed to show internal vertebral venous plexus. Brachiocephalic vein, jugular veins, aorta and carotid arteries also shown. Anterior views. 1 illustration of spine and occipital bone shown with external venous plexus, jugular veins, posterior view. 1 illustration of spine divided in sagital section to show internal vertebral venous plexus. Superior and inferior vena cava, azygos vein, brachiocephalic vein, jugular veins, aorta and carotid arteries also shown. Medial view.