RADIOGRAPHIC MENSURATION CHARACTERISTICS OF THE SAGITTAL LUMBAR SPINEFROM A NORMAL POPULATION WITH A METHOD TO SYNTHESIZE PRIOR STUDIES OFLORDOSIS

Standing lateral lumbar radiographs of 50 normal healthy subjects were retrospectively selected for evaluation of lumbar lordosis. The objec tive was to evaluate, in a normal population, global and segmental con tributions to lordosis in the standing position, and to devise a metho d to compare the seemingly unrelated multitude of lordotic values in t he literature. Because of a variety of positioning and measurement met hods of lordosis in live subjects and cadavers, correlation of results is difficult. While often relying on simple pain questionnaires, stud ies of normal subjects rarely have complete medical history, physical, neurological, and orthopedic examinations. Standing lateral lumbar ra diographs of 50 subjects, who had complete histories and normal examin ations, were analyzed to determine overall lordosis, segmental contrib utions, and vertical sagittal alignment. Using posterior body tangents , the mean L1-L5 angle was -39.7 degrees, Cobb(T12-S1) = -65 degrees, Ferguson's sacral angle = 39 degrees, pelvic tilt angle was 49 degrees , and average RRAs (segmental angles) were RRA(T12-L1) = -3.6 degrees, RRA(L1-L2) = -4.1 degrees, RRA(L2-L3) = -7.6 degrees, RRA(L3-L4) = -1 1.7 degrees, RRA(L4-L5) = -16.80 degrees and RRA(L5-S1) = -32.4 degree s. Using segmental rotation angles as a method to compare past and cur rent literature, a normal standing lumbar lordosis of Cobb(T12-S1) = - 61 degrees, range -55 degrees to -65 degrees, was determined with spec ific segmental angles.