A probe (20, 30, 40) for application to a selected area of a subject's skin covering a body part, which selected area serves as a measurement site for measuring changes in the pulsatile arterial blood volume thereat, comprising: a base (21, 31, 41) for application to the selected area of the subject's skin at said measurement site; a pressure applicator (22, 32, 42) carried by said base (21, 31, 41) for applying a static pressure to the subject's skin at said measurement site when said base is applied thereto; and a sensor (23, 33, 43) carried by said pressure applicator (22, 32, 42) for sensing changes in the pulsatile arterial blood volume at said measurement site when the base is applied thereto; an adhesive layer (24, 34, 44) arranged to adhere a surface of the base (21, 31, 41) within which the pressure applicator (22, 32, 42) is centrally carried to the selected area of the subject's skin so that the pressure applicator (22, 32, 42) pressurizes said selected area measurement site to a predetermined said static pressure; characterized in that said pressure applicator (22, 32, 42) comprises an elastic material configured to apply to said measurement site, by adhering of the adhesive layer of the base (21, 31, 41) thereto, a predetermined static pressure, wherein the predetermined static pressure is selected to be of a sufficient magnitude to partially unload the wall tension of, but not to occlude, the arteries at said measurement site such as to substantially prevent venous distention and blood pooling at said measurement site by applying sufficient external counter pressure to effectively collapse the underlying veins and limit the local venous blood flow to the arterial throughput while permitting free venous drainage with respect to said measurement site through tissues surrounding said measurement site; and in that said pressure applicator (22, 32, 42) is configured to apply said static pressure to a relatively restricted area of the subject's skin, which area occupies a small fraction of the surface perimeter of the respective body part at said measurement site, to thereby permit free venous drainage from said measurement site via a wide region of unrestricted passageways surrounding the measurement site. a base (21, 31, 41) for application to the selected area of the subject's skin at said measurement site; a pressure applicator (22, 32, 42) carried by said base (21, 31, 41) for applying a static pressure to the subject's skin at said measurement site when said base is applied thereto; and a sensor (23, 33, 43) carried by said pressure applicator (22, 32, 42) for sensing changes in the pulsatile arterial blood volume at said measurement site when the base is applied thereto; an adhesive layer (24, 34, 44) arranged to adhere a surface of the base (21, 31, 41) within which the pressure applicator (22, 32, 42) is centrally carried to the selected area of the subject's skin so that the pressure applicator (22, 32, 42) pressurizes said selected area measurement site to a predetermined said static pressure; characterized in that said pressure applicator (22, 32, 42) comprises an elastic material configured to apply to said measurement site, by adhering of the adhesive layer of the base (21, 31, 41) thereto, a predetermined static pressure, wherein the predetermined static pressure is selected to be of a sufficient magnitude to partially unload the wall tension of, but not to occlude, the arteries at said measurement site such as to substantially prevent venous distention and blood pooling at said measurement site by applying sufficient external counter pressure to effectively collapse the underlying veins and limit the local venous blood flow to the arterial throughput while permitting free venous drainage with respect to said measurement site through tissues surrounding said measurement site; and in that said pressure applicator (22, 32, 42) is configured to apply said static pressure to a relatively restricted area of the subject's skin, which area occupies a small fraction of the surface perimeter of the respective body part at said measurement site, to thereby permit free venous drainage from said measurement site via a wide region of unrestricted passageways surrounding the measurement site.