Modern traumatology and orthopaedics is inconceivable without high-quality X-rays diagnostics. In the recent years special equipment that enables to obtain the length-measured images of different parts of a human body was introduced into clinical practice. The details of examination process, i.e. the position of a patient, position of an extremity and many others require special knowledge and experience. The aim of the study is to optimize the possibilities for obtaining the length-measured images of the different parts of a skeleton using modern X-rays equipment. The peculiarities of the determination of segments’ axes and length in patients with lower extremity deformities and shortening are presented; the most typical mistakes are analyzed. The results of the study are of great importance for medical expertise as well as for data documentation in practical, scientific and teaching activities.