We developed the OBR-Scolio ontology that models scoliosis as pathological state of spine using the method of extracting from the FMA reference ontology in anatomical domain and the principal ontology framework of the OBR reference ontology, which is spread over anatomy, physiology and pathology domains. Following the FMA modeling framework, OBR-Scolio ontology initially is created in Protégeé using its frame based representation. In order to enable more powerful reasoning support, ontology visualization, and more precise concepts' definition and description, we converted OBR-Scolio in OWL DL language, due to its higher expressiveness. The paper addresses and discusses the key conversion principles, as well as our experience in such conversion, and the results obtained from Racer reasoner.