A method for interactive adjustment of a 3D ultrasound image of an object includes acquiring a loop of 3D image data of the object, and providing a 3D image of the object on a display for user viewing. The connecting device, in a compressed state, contacts at most one of the first and second terminals, and, in a released state, electrically connects the first and second terminals. The recessed part forms an angle of no more than an angle of about 20\xb0 with respect to a vertical line.