Few things are as entrancing as the extensor expansion. Especially when you stop to think that the muscles and tendons grow from opposite sides to meet each other, it's incredible how reliably it works out. Nerve plexi are incredible, too, but they then take the easy route and just hitchhike on the vessels. How lazy is that? The force transmission in the lower limb is much better organized. On the downside, both both nerves and trusses get damaged readily, and you can get some pretty funky gait conditions as a result.
Oh, gods.
I'm never going to stop analyzing passerby, am I?