A clinical study was performed in order to determine if healthy test subjects can differentiate between adjacent and separated pairs of vertebrae in the lumbar spine. The variable of interest was number of correctly specied pairs of vertebrae. The test subjects were evaluated in terms of sensitivity and specicity of this test. Bootstrap resampling was applied in the data analysis. The results clearly indicated that the test subjects in this study were able to successfully determine whether a pair of adjacent or separated vertebrae was tested during the procedure.