Tuesday, April 24, 2012

Joints

Neurologist: "Okay, so you're a physiatrist, right?"

Me: "Yup." (whatever that is)

Neurology: "So which way is internal rotation of the hip? Is it like this?" [internally rotates her hip]

Me: "Yeah...." (is this a trick question?)

Neurologist: "Because I heard when you internally rotate the hip, you are actually externally rotating it in its socket."

Me: "Um...."

Neurologist: "Maybe I'm thinking of another joint? Where when you internally rotate it, you are actually externally rotating it? What joint is that?"

Me: "Not one that I've ever heard of."

I asked another physiatrist about this, who does a lot of musculoskeletal medicine. His response was: "I think the kind of joint she is talking about is only legal for medicinal purposes."

Do you know what she was talking about?

17 comments:

  1. This comment has been removed by the author.

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  2. Ummm... I might. There seems to be a confusion related to this, given that if you do this with a bent knee, when the thigh faces inward, the foot points outward and vice versa. Confusion to such a degree that we had been warned about this in anatomy class. With the obvious consequence that I was forever confused by it until I got AMPLE practice at the following sentence: Lower extremity is shortened and externally rotated.

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    1. I agree with this. The later comments are far too detailed and complex for a neurologist to know (I'm being serious).

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  3. took me a minute, but eventually I got it. I think it's a joint only people in Amsterdam have.

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  4. I think what he means is that when you internally rotate the leg, moving it toward midline, the actual head of the femur moves posteriorly in the acetabulum. And when the leg is moved away from midline, the head moves anteriorly. But it seems that that would be true for any ball and socket joint. Wait, now I'm confused...

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    1. I think you're correct.. and I'm confused as well. ha!

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    2. I also think that's right. That's how a physical therapist explained it to me when I watched her demonstrate good hip and leg position (femur rotated slightly outward to keep the head securely in the acetabulum) for a patient post hip-dislocation reduction.

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  5. I believe I've hurt myself while trying to figure this out.....

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    1. ROFL!! This made me laugh. I always found MSK to be a weakness and this question just proved it.

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  6. Maybe he was referring to the fact that the thigh adductors medially rotate the femur? That was always as clear as mud to me.
    From my anatomy website:

    Question: Why do adductors medially rotate the femur?

    Most of the adductor group of muscles attach on the posterior surface of the femur, so it is always a mystery how they medially rotate the thigh. If you look at an articulated skeleton while you read this, it will all become clear.

    If the femur was a perfectly straight and round cylinder and you attached something to the back of it, like the adductors attach, the cylinder would rotate laterally when you pulled medially on the back of it. However, the catch is - the femur is not a perfectly straight cylindrical shape. It bows anteriorly, quite a bit. Think of it as a bucket handle. If you grab a bucket handle, either from the back or the front, the bucket handle will move toward you when you pull. If you are an adductor and you grab the anteriorly bowed femur, it moves toward you, pivoting on both ends like a bucket handle (which connects to the bucket at both ends). Now, imagine you flex the hip, lifting the leg to take a step forward. The flexion of the hip makes the femur act even more like a bucket handle, so that the pull of the adductors lies in front of the pivot point of the head of the femur. Adductors pull the femur toward the pubic ramus, medially rotating the femur and counterbalancing the lateral rotational force of the big extensor of the hip - gluteus maximus.

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  7. this sounds familiar -- i think we touched on it (hee hee, pun) in an OMM lab because fellow students were getting confused, and i think snarky scalpel has the right issue -- but at this point i'm finding the question more confusing than whatever was confusing the questioner. (if that parses...)

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  8. I think it may be what ccollier is saying. One of my SPs recently confused the life out of me by having me palpate the hip joint during internal and external rotation and saying something like what that neurologist said. I think they may all be just as confused as I was about it!

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  9. Physical therapists can be amazing for demonstrating/explaining this kind of thing, and making sure the learner understands.

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  10. With the hip and knee both flexed to 90 degrees rotation that brings the foot towards the midline externally rotates the hip (and moving the foot away from the midline internally rotates the hip). This is a never ending issue of confusion for early med students, and probably also the point at which future neurologists stop learning MSK exam.
    As long as you just consider what the hip is doing it is all very simple, but some people seem to focus on the movement of the foot, and get this mixed up consistently.

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  11. Dr. J: Exactly. Now, if everyone just said 'hip in, hip out, end of story' in anatomy class, we'd be fine. As soon as they started warning us of the foot... lost case.

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