Charges for procedure done without consent

Upon the recommendation of my internist, I saw a specialist for a

hormone-related problem. On the day of the appointment, the nurse

instructed me to go to the bathroom and leave a urine sample. I

explained that I was there for a gynecological issue and did not have a

urinary tract infection nor any bladder symptoms whatsoever and,

therefore, did not need a urinalysis and culture. Since I did not deem

this test necessary and nobody explained otherwise, I thought that was

the end of it.

Instead, while I was laying on the exam table half undressed and the

doctor was supposedly conducting a gynecological exam, she inserted

a catheter into my bladder. This caught me totally by surprise as

nobody discussed this with me or asked me beforehand whether I was

willing to undergo the procedure.

The test turned out to be totally unnecessary as the lab results were

negative. However, I just received a bill which includes $337 in

additional charges for this procedure which took a minute & was done

without my consent.

Is this legal? Can a doctor do this type of invasive procedure without

obtaining your approval? And can I be held liablefor the charges?