The CIMI WG recommend changing the implementation strategy for complex body location structures from a resource to a data type to eliminate implied overlap with condition and to support a reusable body structure shared across conditions, observations, procedures, specimens, etc...

We propose the following profile as a starting point for this datatype:

http://models.opencimi.org/ig/skin-and-wound-fhir-profiles/StructureDefinition-BodyLocationExt-definitions.html

Until a decision is made, the CIMI WG intends on using an extension to address this need for current versions of FHIR. We find the standard extension for body site to be problematic as stated above.