Measuring Leg Length

How do you assess a patient to see if they have a leg length discrepancy? If they do, what could it mean exactly? (Is it an instability in the hip, a muscle locked short or long, etc) If it is not a true LLD, would you attempt to fix it? If so, what would you do? Lastly, do you think trainers should be looking at this before we begin a session and trying to fix it?


There are probably a couple ways to measure leg length, but the valid by my standards (I don’t know what the literature says) is this.
Tape measure from ASIS to medial malleolus.
For better at least intra-rater reliability, I would suggest thumbing up from underneath the bony landmarks, and measure from where the button starts to jut out. This way you can have a good shot at measuring the same way every single time.

I'm saying medial malleolus to ASIS

You can measure standing bilaterally, standing on 1 leg, and then laying down in the both positions also.
If there is a consistency, then there is really a leg length difference. If there is a difference standing vs. unloaded, it’s a muscular tension somewhere.

If it is a very real structural difference, the shoe can be built up.  Or you can have an osteotomy somewhere if you want.  That might not be preferrable though.
If it’s a muscular dysfunction, it can/should be fixed.

I would say you probably don’t need to be looking at it, especially at first, because if it’s real, I’ve got to think the person already knows. If it’s functional, it will come out in the wash with the FMS asymmetry.
I typically discard anyone that tells me they have a leg length discrepancy especially from another clincian. It’s part arrogance on my part, and part I know the reality that it will come out as we go through the movement screening and assessment. Leg length itself is a Test. It doesn’t tell me enough.

I think the key here is this.  Always look at dynamic patterns first.  If the person moves well, that is all we care about in the first place.  If there are major problems or asymmetries that show up, they should be addressed.  Tag out if you have to.
But static postural tests and exams should only come after movement has been exposed to be in error.

Like most things, leg length should come out in the wash.

  • January 31, 2012

Leave a Reply 7 comments

drcbdc Reply

I agree with you CW. Limb length is a weak biomarker. None the less, it could drive some form information. As my mentor speaks “there are many roads to Rome.” Perhaps limb length would be an alley. Could provide a short cut but also a dead end. Limb length and squat are similar they may show us something but what does it mean?!!? Other baselines are more important to drive clinical treatment.

debarshi Reply

A tape measure is typically used to measure the length of
each lower extremity by measuring the distance between
the anterior superior iliac spine (ASIS) and the medial
malleolus and is referred to as the ‘‘direct’’ clinical method
for measuring LLD . However, differences in the
girth of the two limbs, and difficulty in identifying bony
prominences as well as angular deformities can contribute
to errors using this clinical measurement tool. Moreover,
there are certain causes of LLD such as fibular hemimelia
and posttraumatic bone loss involving the foot where a
significant portion of the limb shortening is distal to the
ankle mortise. Thus, it may be more accurate to measure
the true length from the pelvis to the bottom of the heel as
it is more easily reproducible and can account for shortening distal to the ankle. In some cases, lengths of the
appendicular skeleton may be equal, but apparent shortening may result from pelvic obliquity or contractures
around the hip and knee joints. An apparent leg length can
be measured from the umbilicus to the medial malleoli of
the ankle

Sandy Kerr Reply

I had bilateral hip replacement last year and was healing well with no SI pain. I have the hips you can run and exercise with but overdid it one day in August when asked by PTs to leap side to side down floor and back. As I had on new nikes my foot stuck to the slip-proof carpet on the first leap. I flew sideways in an arc and stuck out my left arm/hand to “break” my fall. Instead I broke my wrist in two places. It is healing well, but all that time in a cast seemed to trigger the SI pain on the opposite side (right). My left wrist is better but not 100percent yet, but my SI pain seems pretty much every day. Nothing seems wrong with my back and I do stairs and exercise. The new hips cause no pain, but this SI pain is pretty anointing. Any ideas to help it? S. Kerr

Charlie Reply

Sandy – My best advice is to get this checked by someone competent. There are no direct links to wrist function and the SI that I am aware of, so this is very interesting.

hkayman Reply

Hi! Glad to see ur site just now. 75 yrs old active man except leg difference. Right leg is shorter by 6 mm. This is done by MRI at hospital. In fact the actual reason for leg difference is left leg femur is either bend or twisted. Physiotherapy clinic tried to rectify it but could not do any correction. Got shoe inserts. No use. Spend over $ 2500/- so far but no luck.
Could you give some suggestions to correct it? Thanks Is thewre any way I can contact you to discuss and send other details


Jamie Reply

how can a patient with no legs be measured. Do you measure by laying the patient down and measuring the head to the amputee

Charlie Reply

Not sure leg length can be measured……………..without legs.

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