(UK, 1960). We had regular visits from school nurses, but these were usually to check our hair ( for headlice) general hygiene and skin conditions such as scabies and impetigo. These were not medicals, so you did not have to undress. There were also visits from school dentists, which were pretty terrifying. Most children of Junior School age (7yrs -11 yrs) had two school medicals during that time. Because of an ongoing ( but improving) medical condition...I had to have an annual medical ( simply joining another class or year group if my own class was not involved).
There was not a huge emphasis on privacy in my tough, working class, East Midlands school. To minimise disruption.....all of the boys in a particular class had to go to the school hall, taking a reading book and a library book with us. PE benches were arranged around two walls. We stripped down to our vests and underpants and then sat on the PE benches (putting our clothes either behind or under the benches). We were supposed to sit in silence, reading, until our names were called out. The teachers did not mess about. Anyone caught chattering or whispering was hauled out and either spanked or slippered ( sometimes both) in front of everyone else. Very embarrassing in just your undies.
A series of screens had been set up in one corner. The procedure was always the same when your name was called. A school nurse would do the usual routine checks: hair, scalp, fingernails, toenails, hands, feet. Height, weight etc etc. All very brisk and perfunctory. She would then write up notes, while you waited to be called by the doctor ( who was behind another set of screens). Whilst I was waiting,a friend of mine emerged from the doctor's area, completely naked. He spent a few seconds putting his vest and pants back on, before rejoining the others in the hall.
When it was my turn to see the doctor...he did all of the routine things. Shining a light into my eyes, ears and mouth. Taking my temperature. Wooden spatula on the tongue (" Say..Aaahh"). Blood pressure. Reflexes tests. Vest off for stethoscope ( chest & back) tapping the back / chest, palpating the abdomen etc.
Finally ( all of my jolly, avuncular 1960s docs used to say it). "Now, we're just going to check down below and look at your back passage. So, just slip your underpants off for me. There's a good lad." Conditioned to obey without question....I did, standing naked as he felt my boyish cock and palpated my juvenile balls. No one had ever done that before. It was a strange feeling, but not unpleasant. I was embarrassed about having to present my bare bottom to the doctor. Finally, he told me to take my things and get dressed. I picked up my vest and pants and returned to the nurses area to dress. Still naked, I met the next boy going in. I put on my underwear, returned to the hall and resumed reading. When the whole class had been examined, we all got dressed and then returned to the classroom. I was aged 7.