Biceps are really thin at the top?

[Matt11222]

So with my arm outsretched(bicep relaxed) the top of my bicep, where it connects to the shouler, feels really thin. I'm talking like 2-3cm wide. Infact, if I rotate my arm 90degrees infront of a mirror and tense, I can see my tricep behind this thin bit. Is this normal, or are my arms weird

[TolerantLactose]

You mean a muscle nearly fully stretched looks smaller than a muscle twice its size almost fully contracted? Yes, that's normal.

[sunsean]

I think I know what you mean and that is mostly genetic. My arms look big from the sides but thin from the front. You can make the arms bigger but those dimensions are genetic.

[Matt11222]

You mean a muscle nearly fully stretched looks smaller than a muscle twice its size almost fully contracted? Yes, that's normal.

no I mean where my bicep connects to my shoulder it's really thin, when I see pictures of other peoples biceps with a low bodyfat they're almost like a perfect rounded cylinder whereas mine are thick at the bottom(towards the brachioradialis) but very thin at the top, so thin in fact my tricep overlaps it