Word-Request – What is the Protruding Backside of a Car Called?

In the UK they are muntins, or glazing bars.

In the double-glazed replacement window market they are often called Georgian bar.

http://ravensbyglass.co.uk/domestic/georgian-bargwpp/

There are "anklets", which are worn around the ankles.

From Wikipedia:

An anklet, also called ankle chain, ankle bracelet or ankle string, is an ornament worn around the ankle.

Note that "ankle bracelet" in some contexts could be misconstrued as an ankle monitoring device used in law enforcement.

Also, please note that "bracelets" are worn around the wrists. It is clear and natural to say someone wore a bracelet on their arm, but most native speakers will take that to mean it is on that person's wrist. I think the object in your picture would be worn on the upper arm, and therefore is not a bracelet.

There is something called a "bangle". Here is Wikipedia on bangles, for convenience:

"Bangle" on Wikipedia

But yes, in some cases you would simply say "jewelry". (I suggest not calling it a "jewel") Leg-jewelry is little bit odd, so, personally, I would rearrange the phrase to say (He wore) "jewelry on his leg".