It wasn't till after downloading the photos that I found something I have never seen before. Through my contacts I received 2 different points of views.
After hand feeding/raising over 200 baby hummers and tending to even more injured adults, I can assure you that neither the "bent" tongue or the "chop licking" is normal. Whenever we saw such things the tongue was what we termed "broken" - usually though physical injury. We also saw many who had developed an infection in the tongue mechanism (usually Thrush from nectars made with honey) and could no longer retract the tongue; which then went on to be the usual cause of broken tongue. It is a pretty delicate mechanism and not designed to be out waving in the wind when they are flying.
The one photo clearly shows the “joint” you referred to. Hummingbird’s tongues are composed of two parts, a hypoid apparatus and the actual slender tongue. The hypoid apparatus curves up over the hummingbird’s skull and act as a flexible sliding anchor for the tongue. The location where the hypoid apparatus and tongue come together is the “joint” you are seeing in the picture. This two-parted tongue structure is why a hummingbird can extend its tongue so far out of its bill.