Where does “tarsitis” come from?

tarsitis (English) comes from English itis, from English -itis, from New Latin -ītis, from Ancient Greek -ῖτις — female equivalent of -ίτης.

tarsitis (English): Inflammation of the tarsus of the foot;...

Definitions

Step	Language	Word	Meaning
1	English	itis	A medical condition accompanied by inflammation;...
2	English	-itis	Suffix denoting diseases characterized by...
3	New Latin	-ītis	—
4	Ancient Greek	-ῖτις	female equivalent of -ίτης