Anatomical Crypt

[Otis]

Back part of forearm (4)

 

[Dr.Peterson]

Back part of forearm (4)

Spoiler

Back = REAR

part of (hidden within) foREARm = REAR

I was certainly tempted to think about reversing ULNA.

 

[Otis]

tempted to think about … ULNA

I'm glad to see that, but no one can backhand your answer.

Heh, this reminds me of a time when I tried to counter Denis with a mathy crypt, using the other bone. As I recall, it didn't pass muster.
[imath]\;[/imath]