Yes, we are all twisted: Part 1
Developmentally speaking, that is. Version and Torsion are the words we need to know. There are 3 normal versional changes that take place in the lower extremity development from infant to adult: rotation of the talar head/neck, tibial rotation, and femoral rotation (see above).
So, what is the difference between a torsion and version?
A version is a normal variation in the “twistedness” of a limb (longitudinally speaking) between its proximal and distal portions, representing a normal range of development (see femur above) . An example is the head and neck of the femur has an angle of 8-12 degrees with respect the femoral condyles.
A torsion is the same condition with the amount of twist 1 to 2 standard deviations greater. An example is when the angle of the femoral neck and greater than 15 degrees, the condition of femoral ante torsion exists (see photo above).
There are at least 3 reasons you need to understand about developmental torsions and versions that occur with growth:
- Since they occur in the transverse (horizontal) plane, they affect the progression angle of the foot and thus gait
- They affect available ranges of motion of a limb (ex the femur needs to internally rotate 4-6 degrees for normal gait) and can cause pain and/or gait alterations
- They can affect the coronal (frontal) plane orientation of the lower limb, which can affect gait and shoe choices. A Rothbart foot type with an elevated 1st metatarsal head will often result in a varus (or inverted) position of the forefoot with respect to the rear foot.
In this series, we will explore these 3 major versional changes, one at a time.
The Gait Guys. Bald? Yes! Good looking? You bet! Yes, we are a little more twisted than most folks : )
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