De la cabeza a los pies — from head to toe. Learn each part of the body with its article: you'll need the article the moment something hurts.

Start with the head:

Spanish	English
la cabeza	the head
el ojo — los ojos	the eye — the eyes
la nariz	the nose
la boca	the mouth
el diente — la muela	the tooth — the back tooth, molar
la garganta	the throat
la oreja	the ear (the outside)
el oído	the ear (the inside, for hearing)

Spanish has two words for ear. The oreja is the part you can see; the oído is the inner ear — so an earache is dolor de oído.