00:00
So, we're going to start with the cervical spine and I always start with the #5 because
cervical roots 1, 2, 3 and 4 are more involved with muscles around the neck and they're
a little bit more tricky to tease apart and more importantly people rarely get
radiculopathy involving those nerve roots. So we'll start with C5 and I like to envision that
you draw a #5 and then if you actually tilt that #5 90 degrees and have it flat and then
put another #5 mirroring that on the other side we actually start to get the shape of a
person who is actually flexing their muscles. They're actually showing off their biceps and
at the same time they have got their shoulders abducted, which means that they are
flexing their deltoid muscles. So, it turns out that that simple mnemonic helps us to
remember that the C5 nerve root is innervating your biceps muscles and your deltoid
muscles. "So how about just with your right arm, show me your C5s." So, by him doing this
position, he is showing me his deltoids and showing me his biceps. This is the C5 nerve root.
01:10
Next up, we'll do C6 where I want him to extend his wrist, like so. That's C6. And very
simply the other way, it's just lifting your wrist up and that's C7. Now you'll know it by
the way when I say strength, you really want to make sure you're isolating one joint
at a time. A lot of times I see people when they're testing strength they'll do something
like this. "Put your hand up like this and now push me away." When he does this, now
he's winning because he's stronger than I am." I am testing his deltoid muscle, the
stabilizing forces around his scapula, his rhomboids, he is doing his triceps muscle in this
case and his wrist extensors all at the same time. That is not an effective way to assess
or to locate a specific area of weakness. So instead, "Go like up this again for me. Now I
want you to push me away." I'm now testing a single muscle group. Just the muscles that
work around to extend his elbow. So it's important to really make sure you're isolating
your muscle groups by going basically just hold between 1 joint and the next to make sure
that you're not going to get confused. So again, start off with C5. "Go like this for me
and I'm just going to push down." That's his C5s. "Up like this." This is also C5s. Now we'll
do C6. "Put your wrist out like this, or flip them over like this, excuse me." And wrist
extension and I'm just going to pull up, testing wrist extension. That's C6. "Now have your
wrist go up, and I'm going to pull down." That's wrist flexion which is C7. C8 and T1 all
involve the interosseous muscles and the muscles of the thumb. It's not important to
know exactly which one is which. It's just important to know how to test very quickly the
musculature of the hand so I simply do this exercise. "Put your fingers out like this. And
we do finger cutting where I just want you to basically squeeze my fingers with your
fingers. Perfect. Make an okay sign. And don't let me pull through. Great. Haha. Pulled
through but that's okay." "I'm ready." "That's okay, you'll do the same thing on both
sides." Anytime you're checking strength, you're always want to be comparing 1 side and
then the other to make sure you're able to get an accurate control group in a person
who has symptomatology. So this is C5, C6, C7, C8, and T1 are going to involve the thumb,
the opponens pollicis brevis and the interosseous muscles here in the hand. So guys
we're about to move on to assessing strength. It's important for us to use the right
terminology to describe how strong somebody is or how weak they are and there's an
accepted scale that we use from 0 to 5, 5 being full strength and 0 meaning we don't feel
any muscle activity whatsoever. So 5 strength, "Put your arm up for me like this." And he
can push me away with ease. He's got full strength in his triceps in this case. 4 out of 5
is actually broken up into 3 parts; 4+, 4, and 4-. 4+ is 75% strength so he's still going to
probably win, but I will be able to fight back. 4 is just 50% strength, it's clearly going to be
noticeably weaker. And then 4- is only 25% strength. From 4 to 3, means that if he was
lifting his biceps he could lift it against gravity so that's at least a 3. But if I pull down
on his arm, he's no longer able to compete against me with gravity. So it means you
can only lift against gravity if you have 3 out of 5 strength. "So go ahead and show me
3 out of 5." And I'm going to resist them and now he can't fight back. 2 out of 5 strength
is where, while he couldn’t lift against gravity, he can still move the arm left and right
which is where gravity is not competing with him. "So just move your forearm left and
right there." So that's 2 out of 5 strength." And then lastly, 1 out of 5 strength is where
I can feel his biceps tensing, I can feel him trying to move but he actually doesn't have
enough strength to actually move his forearm in space. So that will be 1 out of 5 strength
as opposed to 0 out of 5 strength which is there's just no muscle tone whatsoever.