The present disclosure relates to a measuring tube for conveying a liquid, comprising a tubular section and at least one tubular branch for accommodating at least one component of a measuring device. A first end region of the tubular branch is arranged at or in an opening in a wall along a longitudinal axis of the tubular section. According to the disclosure all points of at least a first portion of the wall, such as an inner surface of the wall, of the tubular section, which first portion defines the opening, are located in a plane. Furthermore, the present disclosure relates to an arrangement for determining or monitoring at least one process variable of a liquid in a pipeline, comprising a measuring device and a measuring tube of the disclosure.