To date a uniform set of standards for the kinesiology and measurement of the degree of flexibility of the human body are not available in Japan. In the methods of measurement of the suppleness of the human body, various distances and angles have been used separately as frames of reference. In the selection of angles for lateral observation on the human body, some investigators have set the standard point of reference at the major trochanter, while others have taken the anterior superior iliac spine as their standard point of reference.
In the present study, the lateral angle of the human body was measured using the anterior superior iliac spine and the major trochanter as the standard points. The values from the measurement of these two points were comparatively studied around the rotation of the pelvis. In 4 male and 4 female university students without joint abnormalities, measurement was carried out in 5 postures (1) normal (2) lordosis (3) flat back (4) flexion of the trunk (5) hyperextension of the trunk.
As the standard points for angle analysis, 4 points, the acromion, anterior superior iliac spine, the major trochanter, and the lateral malleolus were selected. As the angle to express each posture, the anterior angle of the acromion-anterior superior iliac spine-lateral malleolus and anterior angle of the acromion-major trochanter-lateral malleolus were measured.
For the observation of pelvic inclination, the internal angle of the anterior superior iliac spine-major trochanter and the lateral malleolus was measured. In order to analyze this, the range of fluctuation of the postural angle against pelvic inclination around the major trochanter and anterior superior iliac spine was calculated.
As a results, a small variance in the fluctuation of the values of measurement in each test subject would express a change of posture due to pelvic rotation. In each case, the use of the major trochanter gave a small unbiased variance.
In our experience, palpation of the major trochanter or anterior superior iliac spine especially in females revealed less resistance by the former. Consequently, based on these results, the use of the tip of the major trochanter appears to be more reasonable than the anterior superior iliac spine as a reference point for the observation of the human body from the lateral aspect.
It is proposed that the standard point should be placed on the center of the major movable joint to express the posture and other movement, in addition to the anterior superior iliac spine.