Letters to the Editor  |   November 2008
Author Affiliations
  • Dale E. Alsager, DO, PhD
    Osteopathic Medical Services Inc Maple Valley, Wash
Article Information
Imaging / Neuromusculoskeletal Disorders
Letters to the Editor   |   November 2008
The Journal of the American Osteopathic Association, November 2008, Vol. 108, 630. doi:
The Journal of the American Osteopathic Association, November 2008, Vol. 108, 630. doi:
I agree with Dr Magoun that Dr Rancont1 provided an excellent and detailed osteopathic structural evaluation for the patient described in his September 2007 case report. Indeed, I agree with most of Dr Magoun's statements regarding physical diagnostic and treatment techniques for patients with pelvic, lower extremity, and sacral somatic dysfunction. I also agree that a reasonable sequence of events in the clinical setting includes conducting osteopathic diagnosis and treatment for such patients before the use of radiographic evaluation. 
However, I respectfully disagree with Dr Magoun about the usefulness of the standing postural radiograph (ie, the Willman2 protocol). The primary purpose of obtaining a standing postural radiograph of the pelvis is to distinguish physiologic (ie, functional) leg length difference from anatomic (ie, structural) leg length difference.3 
In a radiographic evaluation, the line perpendicular to the vertical plumb line, which transects the superior surface of the femoral heads, represents the sum of the length of bone and related arthroidal elements, between the superior edge of the femoral head and the inferior-most point of the leg (ie, where the calcaneous contacts the floor in the weight-bearing configuration). The Willman protocol can be used to detect anatomic leg length difference between the left and right sides—something no amount of osteopathic manipulation will change. 
The Willman protocol is highly reproducible, with structural leg length differences not changing over time—except in cases where fractures or surgery to the leg bones have occurred. I agree with Dr Magoun that sacral base unleveling and iliac crest height variance, which may accompany a physiologic leg length difference, can be influenced by manipulation or somatic dysfunction (eg, counterrotation of innominate bones). Thus, the interpretation of a patient's diagnostic results needs to correlate radiologic findings with clinical findings. 
The Willman protocol is not the only radiographic technique available for measuring anatomic short leg. Many radiologists prefer to use computed tomography (CT) to scan the entire pelvis and the lower extremities. As part of this CT technique, the total bone length in the lower extremities can be easily calculated. However, the CT technique has certain disadvantages that limit its application. For example, CT technology exposes much more of the patient's body to radiation than does the Willman protocol. Furthermore, a CT scan may not be as accurate as the Willman protocol in terms of evaluating anatomic leg length difference because the CT scan does not assess leg length in a weight-bearing stance, in which interarticular soft tissue spaces may distort the total limb length values. Computed tomography is also more expensive than the Willman protocol. 
It is important that certain elements of the Willman protocol be followed carefully during physical examination. For example, the patient should be standing on a floor grid to ensure that the feet are positioned properly and consistently in each examination session. In addition, a steel plumb line must be suspended from the ceiling above the bucky and passed in front of the radiograph film, behind the film cassette-holder surface panel. 
If the Willman protocol is followed carefully, it is brilliant in terms of its simplicity, reproducibility, and cost-effectiveness. 
 Editor's Note: In an upcoming issue of JAOA—The Journal of the American Osteopathic Association, Christopher M. Rancont, DO, will respond to this series of letters regarding his case report (2007; 107:415-418).
Rancont CM. Chronic psoas syndrome caused by the inappropriate use of a heel lift [case report]. J Am Osteopath Assoc. 2007;107:415-418. Available at: Accessed October 20, 2008.
Willman MK. Radiographic technical aspects of the postural study. J Am Osteopath Assoc. 1977;76:739-744.
Kuchera ML, Kuchera WA. Postural considerations in the coronal and horizontal planes. In: Ward RC, ed. Foundations for Osteopathic Medicine. Baltimore, Md: Lippincott Williams & Wilkins;1997 : 983-989.