Pulse-wave-propagation-relating information obtaining apparatus and arterial-bifurcate-portion determining apparatus

An apparatus for determining a bifurcate portion of an artery of a living subject that is present under a skin of the subject comprising:

• a pressure-pulse-wave sensor including a plurality of pressure-sensing elements which are arranged at a first regular interval of distance in an arrangement direction over a distance longer than a diameter of the artery, and each of which produces a pulse-wave signal representing a pressure pulse wave propagated thereto from the artery;
• a distribution-curve obtaining means for obtaining a plurality of distribution curves each of which represents a relationship between respective positions of the pressure-sensing elements in the arrangement direction and respective amplitudes or respective minimum magnitudes of the respective pressure pulse waves represented by the respective pulse-wave signals produced by the pressure-sensing elements which are located at a corresponding one of a plurality of curve-obtain positions which are arranged at a second regular interval of distance in a predetermined range in a lengthwise direction of the artery and at each of which the pressure-sensing elements arranged in the arrangement direction traverse the artery;
• and
• a bifurcate-portion determining means for determing, based on the distribution curves respectively corresponding to the curve-obtain positions, the bifurcate portion of the artery in the predetermined range in the lengthwise direction of the artery.