I use the term abacus to describe the areas at the tops of pillars which separate them from the ceiling. In TT99 there is one which runs West-East across the top of each pillar. As the central area of the ceiling has a profile like the hieroglyph for a shrine , both abaci are deeper at the East than at the West end. Rather than leave them blank, the designer/decorator of the tomb filled each with a large snake, before each of which was a cartouche of Thutmose III.
The above photo shows the left part of the abacus; clicking on it will reveal a larger image of the rather damaged head of the cobra at the east end of the southern abacus. The winged cobra can be seen to be holding a sun disc; under the very dirty area was probably a cartouche as on the other side, confirmed by the hieroglyphs to the left reading 'perfect god'. These only are used to refer to the king.