Prosecutors say Lil Nas X allegedly assaulted and injured three police officers as they were trying to take him into custody early Thursday … and now we’re getting a sense of what the alleged injuries include.

Law enforcement sources tell TMZ … one officer suffered an abrasion on their head, another hurt his hand, and a third suffered a back sprain.

We’re told the cop with the alleged back issue went to the hospital for further medical attention and was sent home for a week to recover.

TMZ broke the story … the “Old Town Road” rapper was butt naked on Ventura Blvd. in L.A.’s Studio City when LAPD offices were called … police say when they confronted Nas, he charged at them and injured three cops.

Prosecutors charged Lil Nas X with four felonies … including three felony counts of battery with injury on a police officer.

Our law enforcement sources are also telling us no Taser was deployed during the arrest and the use of force references in the police scanner audio relate to a “firm grip.”