dermatone over umbilicus

[jackets5]

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this dermatome that lies at the umbilicus to lose sensation you need to cut dorsal nerve root T-10 correct. i took a neuro exam today and it was said that in order to lose sensation over the umbilicus you need to cut doral nerve roots T9-T11 or one level above or below T10. On the exam the answers that were given were T9-T11 and T10 was a seperate answer. I put T10 and the prof. says the answer is T9-T11 is this correct, do i have a leg to stand on to get the question back

 

[IHeartNerds]

No leg to stand on. Dermatomes overlap quite a bit and cutting the T10 root alone would likely not be sufficient.

Also, that you can't spell dermatome, imo, means you should not get credit.

 

[cpants]

No leg. One above and one below to cut off sensation is basic dermatome knowledge.

 

[MSKalltheway]

no Leg. One Above And One Below To Cut Off Sensation Is Basic Dermatome Knowledge.

+1

 

[Jccripe]

Why do we have to know these dermatomes if they vary and overlap so much.
BellyBuT-10

 

[ACSurgeon]

Why do we have to know these dermatomes if they vary and overlap so much.
BellyBuT-10

It gives you a crude idea of where the nerve injury/root compression. When you preform a physical exam and you test for sensation, knowing that the big toe is mainly L5, having pain or reduced (yes you need to damage L4 and S1 to get complete anesthesia) sensation there indicates an L5 compression/injury.

Plus, I don't think anybody requires you to know ALL dermatomes, just the main ones that might be compressed or have other clinical significance.

 

[DickyV]

I think this is a case of some poorly designed answer choices but, in the end, I think T9-T11 is going to be the "single best" answer.

 

[cpants]

I think this is a case of some poorly designed answer choices but, in the end, I think T9-T11 is going to be the "single best" answer.

I think it was designed that way on purpose. Cutting T10 is a wrong answer choice. You will most likely maintain sensation in the umbilicus if you cut this root only. They are testing whether or not you know that the dermatomes above and below contribute to the innervation. The OP did not know that, thus he got the question wrong.

 

[DickyV]

I think it was designed that way on purpose. Cutting T10 is a wrong answer choice. You will most likely maintain sensation in the umbilicus if you cut this root only. They are testing whether or not you know that the dermatomes above and below contribute to the innervation. The OP did not know that, thus he got the question wrong.

I know that's the concept they're going for. Without seeing the actual question (we just have the OP's recollection), I don't know if the answers were clear enough to really go after that fact.

 

[Depakote]

I think it was designed that way on purpose. Cutting T10 is a wrong answer choice. You will most likely maintain sensation in the umbilicus if you cut this root only. They are testing whether or not you know that the dermatomes above and below contribute to the innervation. The OP did not know that, thus he got the question wrong.

I was thinking that this was a perfect illustration of how questions in medical school are asked. You can know the vast majority of what the question is asking about, but unless you have 100% of the material down pat, you're not getting it right.