"in " or "on"?
1. he punched me in my face
2. he punched me on my eye or on one of my eye?
3. he punched me on my nose
4. he punched me on my arm

I have a problem with whether in or on, but I think if you punch in a body part it should be a place where could be concaved by your punch, but if you punch on a body part, it should be a place like eyes where cannot be concaved ( a hard place) by your punch. Am I right?
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5. I got 10 stitches on my toe.
6. I was given an anesthetic in my toe.

when it comes to this situation, why should I use "on" in the point 5 but "in" in the point 6?

Thank you!

Question

"in " or "on"?
1. he punched me in my face
2. he punched me on my eye or on one of my eye?
3. he punched me on my nose
4. he punched me on my arm

I have a problem with whether in or on, but I think if you punch in a body part it should be a place where could be concaved by your punch, but if you punch on a body part, it should be a place like eyes where cannot be concaved ( a hard place) by your punch. Am I right?
---------------
5. I got 10 stitches on my toe.
6. I was given an anesthetic in my toe.

when it comes to this situation, why should I use "on" in the point 5 but "in" in the point 6?

Thank you!

Answer

To me - either 'in' or 'on' is OK for any of those, but my preference would be 'in', including 'stitches in', except possibly 'arm', where perhaps 'on' is more natural.
I guess that fits with your 'concave' idea. But an eye is already concave, so it is 'in'.
I would also use 'in the' or 'on the' rather than use 'my'.

Answer

Thank you Paul!

Answer

In these examples you are saying both me and my. You only need one of them to make the sentence make sense. In the examples you can replace "me" with "the" and it sounds more natural.

So 1) He punched me in the face 
He punched my face is also correct but sounds a little unnatural.

2) He punched me in the eye OR He punched my eye

etc.