A system and method for determining at least one physiological parameter of a subject. The system comprises a sensor for skin apposition. The sensor comprises at least one light source for illuminating of a thoracic bone or a septum, and a detector for measuring of reflected and/or scattered light from blood vessels related to the thoracic bone or septum. The system further includes a control unit configured to control operation of the sensor and an analysing unit configured to analyse the measurement data for determining the at least one physiological parameter.