plural subject pronoun, object body part singular?

Question

Plural subject (nous), a single (non-paired) body part for each person: why the singular for the body parts (la tête) and not plural? "Nous nous grattons la tête"

Accepted Answer

This is a good question to ask. In French, body parts almost always take the definite article if they're referring to the subject's body parts. Using the singular here would be appropriate because the human body has ONE HEAD. If this expression were to occur with a body part (like eyes or ears), it would be appropriate to use the plural definite article because the human body has MORE THAN ONE OF THEM.

Answer

I think it's because you have only one head each thereforecsingular