Surrounding area of a bone (6)
I believe the answer is:
radius
This could be a double definition.
'surrounding area' is the first definition.
'radius' can be an answer for 'area' (thesaurus). I'm not certain of the 'surrounding' bit.
'a bone' is the second definition.
(radius is a kind of bone)
'of' is the link.
Can you help me to learn more?
(Other definitions for radius that I've seen before include "Bone of forearm - distance from centre" , "Centre-circumference length" , "from centre to boundary" , "Half diameter of circle" , "Part of build-up of arms" .)