Definite article for one's own body parts?

Question

Why is it "Mes pieds sont gelés" rather than "Les pieds sont gelés"?  I understood that you could use la, le, l' when referring to your own body parts.  How can you tell which to use?

Maarten Kamp · Accepted Answer

In this case, the body part is the subject of the verb, not the object. "Mes pieds sont . . ."  - as noted in the lesson, this is one of the 'exceptions' to using definite articles with body parts as per the example pasted below (others being for emphasis or when needed to avoid ambiguity in circumstances such as another person/other people involved - these latter 2 reasons are at the speaker's consideration/discretion) :
"Also, when the body part is the subject of the verb (rather than the object), possessive adjectives are used:
J'ai mal à la tête.My head hurts.
BUT
Ma tête me fait mal.My head hurts."

Cécile Janty-Davies · Answer

Hi Rebecca, 
Just to add to what Maarten said, you could also say -
J'ai les pieds gelés 
or
Mes pieds sont gelés 
for, my feet are frozen but it is probably more colloquial.