I am not a teacher nor a student, just someone desperately looking for an answer.
Did I write this sentence correctly: "Bony enlargment affecting the PIP and MCP joints". If I remember correctly, affect is a verb meaning to influence something/someone and effect is used as a noun (like "the medicine's side effects")
I've been looking up in every available dictionary and online site to double and triple check the difference between affect and effect.
You are good to go.
They show the effects (noun) when they have been affected (verb).