"The word disc or its alternative spelling, disk, with a final k in place of the c, are both acceptable spellings in British and American English. However we have made an editorial decision to favour the spelling disc and all its orthographic derivatives."
"Most commonly in radiology, the word disc is used in the context of the intervertebral disc, although is also found in other contexts such as the articular disc within the TMJ or drusen of the optic disc."