"I am lying on my back."
Translation:Я лежу на спине.
I understand that in Russian, possessive pronouns are rarely ever used with body parts, it is automatically assumed that you are talking about your own back here. If that weren't the case, you'd have to specify that it was someone else's. The same way you would never hear "У меня болит своя голова" normally for "my head hurts"
That's not equivalent. У меня already implies that it's your head you're talking about, making своя redundant
for some reason this has me thinking of как левёнок и черепаха пели песню (which I apologise if I've misspelled); я на солнышке лежу...? крокодил-дил-дил плывет... okay I only remember bits of it, evidently, I must go find if and watch it...
When спина was introduced earlier in this lesson, the first definition given on hover was "spine". I used "spine" in my answer and was marked wrong. Now I have found the word in my dictionary, and "spine" is not given as a definition - only "back". This dictionary gives a very different word for "spine". Why did DL give us "spine" as a definition if dictionaries do not support it and DL itself does not accept it as an answer?