WWII era Naval medical pin

Naval medical pin from WWII. Tested sterling silver. Appears to have once had a gold wash. Some traces in creases on front. Appears to have been marked on the back at one time but has worn off. All moving parts function. About 1/2” square. 2.41g. Note: I am categorizing this under men’s accessories even though I have no idea who would have worn this. Perhaps a Navy doctor or a Navy nurse? Needs more research. Happy to learn more if anyone has any information to share.