Yes, "buttocks" is an appropriate term, particularly in medical or anatomical contexts.
In general conversation, the appropriateness of discussing or referring to buttocks depends on the context, the audience, and cultural norms. What is acceptable in one situation might be inappropriate in another.
However, in professional medical settings, "buttocks" is a legitimate anatomical term used for documentation and communication. Medical professionals will use the term precisely to identify a specific location on a patient's body. The location (left or right) is also usually specified in the medical record. For example, a wound on the left buttock would be clearly documented.
