Pakal Votan Tomb Lid: The Serpent Bar

leading from 

Established Mythology behind the tomb lid.

and

The "Pakal Votan" tomb lid  

(source: A Forest of Kings:
The Untold Story of the Ancient Maya)

1. The Serpent Bar, also known as the Bicephalic Bar, the Double-headed Serpent Bar, and the Ceremonial Bar, is a sceptre carried in the arms of the rulers, usually held against their chests. To hold the Bar, Maya rulers put their hands in a formal gesture with their wrists back to back and their thumbs turned outward.(source: A Forest of Kings: The Untold Story of the Ancient Maya)
2. A two-headed serpent bar (the Maya symbol of royalty) is wrapped around branches of the Tree of the World. The body is made of jade segments, again conferring special value on the serpent. The heads on each end of the bar correspond, piece by piece, to the skeletal dragons at the opening to the Underworld. Whereas the Underworld is like a skeleton, Earth, represented by the serpent, has flesh.(Source www.delange.org/PalenqueTomb/PalenqueTomb.htm)