Inventor and Designer of Postural Control Insoles

Short Leg Syndrome (aka Leg Length Discrepancy)

This is one of the most contested subjects on  foot/pelvic mechanics.  An internet search may totally confound you. 

Some internet sites claim that a forward rotation of the innominate bone results in a lengthening of the leg on that same side (e.g., anterior rotation of left innominate bone results in a long left leg). 

Other sites claim that a forward rotation of the innominate bone will result in a shortening of the leg on that same side (e.g. anterior rotation of the left innominate results in a short left leg). 

Obviously this is confusing and makes no sense.  Which claim is correct?

In actuality, the truth is obvious if one looks at the anatomical position of the acetabulum within the innominate bone.  If the innominate rotates anterior/externally (forward), the acetabulum must rotate cephalad and posteriorly (See animation below). 

As the acetabulum rotates cephalad and posteriorly, the femur head, which is securely held within the acetabulum (by the Iliofemoral and Ischiofemoral ligaments), rotates upwards and backwards.  This shortens the leg and hyperextends the knee.


  • Abnormal (gravity drive) pronation results in an anterior/external rotation of both the innominates (Rothbart 2006)
  • Both femur heads are displaced upwards and backwards. 


If the left foot is more pronated then the right foot, the left femur head will be more cephalad and posteriorly displaced relative to the right femur head.  Clinically you will diagnose the patient as having a Short Left Leg Syndrome.

If the right foot is more pronated then the left foot, the right femur head will be more cephalad and posteriorly displaced relative to the left femur head.  Clinically you will diagnose the patient as having a Short Right Leg Syndrome.

Short Leg Syndrome resulting from a pure ascending postural distortion pattern (published study 2006)

  1. Below is a list of 10 original research published papers investigating the relationship between leg length inequality and innominate (sagital plane) torsions.  
  2. Most used a heel lift placed on one leg and then recorded the shift in the position of the innominate bone on that side.
  3. All of the below studies concluded that:
  • Anterior Innominate bone Rotation shortens the ipsilateral leg
  • Posterior Innominate bone Rotation lengthens the ipsilateral leg

      Pitkin H., Pheasant H. Sacrarthrogenetic telalgia. II A study of sacral mobility. J Bone Jt Surg. 1936;18(2):365–375

      Giles L.G. Lumbosacral facetal “joint angles” associated with leg length inequality. Rheumatol Rehabil. 1981;20(4):233–238
      Drerup B., Hierholzer E. Movement of the human pelvis and displacement of related anatomical landmarks on the body surface. J Biomech. 1987;20(10):971–977

     Rothbart BA, Esterbrook L, 1988. Excessive Pronation: A Major Biomechanical Determinant in the Development of Chondromalacia and Pelvic Lists. Journal Manipulative Physiologic Therapeutics 11(5): 373-379.
      Cummings G., Scholz J.P., Barnes K. The effect of imposed leg length difference on pelvic bone symmetry. Spine. 1993;18(3):368–373
      Beaudoin L., Zabjek K.F., Leroux M.A., Coillard C., Rivard C.H. Acute systematic and variable postural adaptations induced by an orthopaedic shoe lift in control subjects. Eur Spine J. 1999;8(1):40–45.
      Young R.S., Andrew P.D., Cummings G.S. Effect of simulating leg length inequality on pelvic torsion and trunk mobility. Gait Posture. 2000;11(3):217–223
      Krawiec C.J., Denegar C.R., Hertel J., Salvaterra G.F., Buckley W.E. Static innominate asymmetry and leg length discrepancy in asymptomatic collegiate athletes. Man Ther. 2003;8(4):207–213

      Rothbart BA. Relationship of Functional Leg-Length Discrepancy to Abnormal Pronation. Journal American Podiatric Medical Association; 2006;96(6):499-507

     Khamis S, Yizhar Z.  Effect of feet hyperpronation on pelvic alignment in a standing position. Gait & Posture; 2007;25(1):127-134


There are many non-original published papers that merely comment on the position of the innominate bone relative to the short or long leg. 

There is no consistency in these papers:  some link the short leg to a posteriorly rotated ipsilateral innominate bone, others link the short leg to an anteriorly rotated ipsilateral innominate bone. 

These papers are opines rather than research based and thus have not been included in the above list.

       Rothbart BA 2006. Relationship of Functional Leg-Length Discrepancy to Abnormal Pronation. Journal American Podiatric Medical Association; 96(6):499-507

  • Abnormal pronation:  right foot > left foot
  • Anterior rotation of the innominate bones:  right > left
  • The right acetabulum is more cephalad and posterior compared to the left acetabulum
  • The right leg appears shorter when supine
  • Both knees hyperextended, right > left
  • Standing, the pelvis tilts to the right
  • This can result in a right thoracic, left lumbar scoliotic curve (See Spinal Study published 2013)

Short Leg Syndrome aka Functional Leg Length Discrepancy 

  1. Short Leg Syndrome is a Symptom of either an ascending or descending postural distortion pattern.

Revised July 29, 2019