2006-07-13 09:46:03 · 14 answers · asked by stevefootballlove 1 in Health ➔ General Health Care ➔ Other - General Health Care
it is the same reason a normal door only opens one way
2006-07-13 09:52:31 · answer #1 · answered by efhire 2 · 2⤊ 2⤋
because thats the way we are meant to be, imagine what it would look like if everyone had arms bending the opposite ways....but we can turn our arms lots of ways and there has to be some control in the joints too hense why we have arms only bending one way.we dont need them to bend the other way anyway.
2006-07-13 10:54:13 · answer #2 · answered by carla_mail03 2 · 0⤊ 0⤋
Obviously the answer is multiple and relates to our gradual evolution to biped mammal. One plausible answe is the blood and nerve supply is carried to the extremities via vessels and nerves. Luckliy for us the bending of the arm in one direction allows these to bend slightly on themselves without cutting off supply. If faced with the other direction, they would inevitably stretch causing damage or at the very least limiting supply. It also allows our joints to lock so we can stand up (knee joint) for example.
2006-07-13 10:00:03 · answer #3 · answered by TheDoc 1 · 0⤊ 0⤋
If they bent both ways yo would be bi-bendable. Oh OK . If your elbows bent bothways you would have to have EXTREEMLY large muscles in order to pick something up without dropping it or having your arms bend the wrong way
2006-07-13 09:52:50 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Because the fossa that contains the ulna on the humerus only goes halfway through anatomically. The capitulum... Those that are "Double jointed" really only hyperextend their arms at their elbows.. they really aren't double jointed. And sometimes when they do this hyperextension they can damage their ligaments.
2006-07-13 09:55:40 · answer #5 · answered by PreviouslyChap 6 · 0⤊ 0⤋
Speak for yourself, both my arms are quite bendy backwards, especially the left one after breaking it when I was 6.
2006-07-13 11:15:13 · answer #6 · answered by Rotifer 5 · 0⤊ 0⤋
You can bend it both ways when it's broken.
2006-07-13 09:49:16 · answer #7 · answered by Art The Wise 6 · 0⤊ 0⤋
well, evolution has decided one way bending is good.
Perhaps in the future we will bend both ways (not me, hetro all the way)
2006-07-13 09:55:16 · answer #8 · answered by realdragonflame 3 · 0⤊ 0⤋
oooh it would be nasty if they went both ways, like Mr Wire man
I am scared of Mr Wire man and his two way bendy arms
2006-07-13 09:53:25 · answer #9 · answered by bronx 4 · 0⤊ 0⤋
So that one doesn't hit themselves in the head from too much bendy swinging while walking. (It's a scientific fact)
2006-07-13 10:03:10 · answer #10 · answered by miss_nursie_nurse 4 · 0⤊ 0⤋