Victorian surgeon's button - information please

[Jamesb853]

I recently acquired the button in the attached scan, which is ex-National Army Museum auction. It is a Medical Staff officer's two-piece mounted mess button dating from c1840-1860 as it has the early Jennens backmark and a typically early soldered shank. It was described as a "mufti button". This has confused me because my understanding of "mufti" is civilian clothes!

Can anyone provide any further information about this button please?

James