Name the dermatomes indicated by the letters A to H and L to R in the figure below.

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College Answer

A = C4,

B = C5,

C = T3,

D = T2,

E = C6,

F = T1,

G = C7,

H = C8,

L = C4,

M = T2,

N = C5,

O = T1,

P = C6,

Q = C8,

R = C7

Discussion

Dermatome distribution seems something that one might expect to see as a part of the ACEM primary. Perhaps this is why the college examiners have decided to spring this on their candidates.

It is difficult to enter into an indepth discussion of such a question. For the purpose of reference, an excellent dermatome map can be found at www.apparelyzed.com.

For the time-poor candidate, a reference of dermatome and myotome maps has been stolen shamelessly from Wikipedia, and posted here at the Required Reading section.

References

References

For a more detailed look, one can see the textbook "Neurosurgical Classics".

Foerster, O. "The dermatomes in man." Neurosurgical Classics (1992): 129. Best viewed in this Googlebook.