A method of measuring an object is described that uses an ultrasound inspection apparatus (56; 330) carried by a coordinate positioning apparatus (50). The ultrasound inspection apparatus (56; 330) includes an ultrasound transducer (92) and a coupling element (104) for contacting and acoustically coupling to the object to be inspected. The coupling element (104) comprises a self-lubricating material, such as a hydro-gel. The method comprises using the coordinate positioning apparatus to scan the coupling element (104) of the ultrasound inspection apparatus along a path on the surface of the object whilst ultrasound measurements are acquired.