FIG 3. M-mode recording of both the internal jugular venous valve and vertebral venous valve. Arrow 1, valve opening; arrow 2, valve closing; VV, vertebral vein; BCV, brachiocephalic vein.
FIG 3. M-mode recording of both the internal jugular venous valve and vertebral venous valve. Arrow 1, valve opening; arrow 2, valve closing; VV, vertebral vein; BCV, brachiocephalic vein.