An apparatus for measuring a characteristic of a body part, such as an infants head, includes a flexible substrate, a plurality of sensing elements provided along the substrate, and an electronic system. Each of the sensing elements (i) has a component wherein an electrical characteristic of the component changes predictably in response to the component being bent, and (ii) provides a signal that is indicative of the current value of the electrical characteristic. The electronic system is structured to receive the signal of each sensing element and determine a measure of a degree of curvature of the sensing element based on the received signal. The electronic system is also structured to determine, based one or more of the measures, a representation of a curvature of a segment, such as a loop, defined by a selected one or more of the sensing elements.