The recurrent laryngeal nerve is a branch of the vagus nerve which innervates the larynx. But, instead of branching off in the neck and travelling directly to the larynx, for evolutionary reasons it follows a long, looping course down the neck into the thorax, before doubling back on itself to ascend back up the neck to the larynx. This circuitous route is why it's called "recurrent".
As well as being perverse and wasteful, from a "design" point of view, this anatomical arrangement makes the nerve much more vulnerable to injury. In fish, it goes direct.
Compared with a putative designer of life, the Universe, and everything, I'm not very intelligent, but I think even I would have ironed this one out. Did she have a good day with fish, but an off day with mammals?
Answers on a postcard, please.
http://www.ghorayeb.com/RECURRENT_LARYNGEAL_2.jpg
Edited by Blzebub, : Naughty title, add picture
Edited by Blzebub, : No reason given.
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