This is rotation of the entire leg:
But the femurs do not comprise the entire leg. They’re only the thigh. If someone is standing like so,
A common mistake is thinking because the feet are turned out => the leg is externally rotated. But the feet are not the femurs! Just because the foot is turned out does not mean the knee is also turned out.
Looking more closely at this person’s left leg, the knee is pointing straight, while the foot is turned out,
The femur, relative to the lower leg, is internally rotated.
While on the right side,
The knee and foot are more lined up. The femur isn’t internally rotated relative to the lower leg. The right leg is externally rotated.
Let’s look at things from the back.
The hamstring insertions provide a guideline for femoral rotation.
Things should look pretty darn symmetrical.
Notice how much more of the medial thigh is showing compared to the lateral,
While even in neutral alignment you’ll always see more of the medial thigh, you should still be able to see a decent chunk of the lateral, or the insertion should at least be pronounced.
From the front, we originally said,
- Left femur is neutral but lower leg is turned out => Femur is internally rotated relative to lower leg
- Right femur and leg are externally rotated
The left leg matches up with what we said earlier- it’s in neutral. You may have even thought the left femur, from the front, was internally rotated.
But we can see there is a decent chunk of the lateral thigh showing.
Meanwhile the right, the leg we said was externally rotated, looks internally rotated! The lateral hamstrings are nearly out of the picture. It’s not a ton, sometimes the lateral insertion is out of the picture, but it’s certainly not externally rotated. The lateral chunk of thigh would be very prominent in that case.
In fact, when we take into account the right femur is internally rotated, but the foot is turned out,
then we can say the femur is even more internally rotated, relative to the lower leg. Same thing with the left. Even though the left femur is in neutral alignment, the lower leg is turned out. Therefore, the left femur is, relative to the lower leg, also internally rotated.
The patella has some mobility to it. It can glide up and down, and side to side.
We need to be careful assessing femoral internal rotation from the front, because we’re relying on the patella as a landmark, but that landmark can move. It’s rare to see a patella excessively gliding medially, but it’s common to see it excessively glide laterally. (Something a stiff IT band can be responsible for.)
The hamstring insertions aren’t mobile like the patellae though. If they aren’t fairly symmetrical from the back view, then a bone, the femur, must have moved them.
- You never want to only use the anterior view of someone -only the patellae landmarks- to let you know if their femurs are internally rotated while standing. We can use the front view, but it’s part of the picture.
- You never want to only use the feet to tell you what’s going on at the femurs. We need to also use the femurs!
Summarizing this person,
- Left femur is in neutral, but lower leg is turned out = Femur internally rotated relative to lower leg.
- Or, lower leg externally rotated relative to femur.
- Right femur is internally rotated and lower leg is externally rotated.
- Right femur looks laterally rotated from front though = likely lateral glide of patella going on at that side (and probably a stiff IT band).
This is important because one might look at this person and say, “Their right leg is externally rotated due to where their foot is,” and subsequently start doing a bunch of internal rotation work, on a femur already in some internal rotation!
You might also see the left leg and go, “Their femur is internally rotated,” and do a bunch of external rotation work. But if you ignore the lower leg, the thing that’s really out of neutral, you might not get anywhere. The femur is in neutral but the lower leg is not. Should you be focusing on femoral external rotation, or tibial internal rotation? (We’ll assume no tibial torsion is going on for this!)
As is always important to mention with posture assessment though, this is merely a starting point for assessing movement. Posture is a window into movement, but you can only see so far through a window without walking through the door. We likely wouldn’t want to take much more from this assessment than whenever this person moves, having a little extra attention to when / if their knees turn in and or their feet turn out.