I remember well that my parents received a letter from the school at home a few days after the beginning of the year school and a few days before the school examination which was mandatory and took place at school.
We could not go to see a family doctor to have a medical form for school, the authorities of the school did not consider it as valuable so the presence to the schoool examination was required each year.
If we were ill the day of the examination of our class, we were summoned an other day with an other class.
The letter from the school mentioned the day of the examination and the requirement for the student to be present, an agreement from the parents who might sign it and was send after to the school but in fact it was impossible for a parent to refuse that his son was examined by the school doctor because it meaned that he could not go to that school and might change of school.
Nothing was mentioned on the letter about the clothes but we were said by the Pe teacher at the first lesson ( generally the school physical examination took place during the time of a PE lesson and it was the PE teacher who supervised us at the locker room near the nurse office where the examination took place.) how it woould be perfomed, not with details about the examination itself, only about the clothes...
He explained us that half of the class would be examined by alphabetic order that day and the other half an other day and that we might wear a clean brief -(at that time all students were wearing white briefs and pretty all the same kind ) and clean socks ( which was in a certain way useless because we were instructed to remove them like all our clothes except our briefs as soon as we arrived at the locker room but may be it was to avoid bad smells or smells of swear in the room ) and that we might come after washing seriously all the parts of our bodies on the morning of that day ( at that time there was a bathing room in very few families, so for most of us it meaned that we might wash our body in the kitchen with a bin normally after 12 age, the mothers left their sons wash themselves without help but it could certainly be different in a few families where the mothers did not trust enough their sons to be clean if they were not supervised and subsequently still washed themselves their sons, at least until may be 14 age).
The day before the examination, a school supervisor came in the class during a lesson to recall us these instructions about clothes and cleanliness.
So the first time it was a little impressive and we were nervous on that day.
Our parents were not asked to fill a medical form before the examination and to ask to questions about our health or our way of life but we might come with our vaccination record.
Nothing was said about genitalia or hernia exams, we discovede how they were performed by the school doctor on the day of examination, nor how much we might be undressed ( which was depending on school doctors or even PE teachers since he was the first to instruct us to undress a the locker room but we guessed that like in primary school we had to undress at least in briefs)
It was pretty the same in high school than in grammar school but we knew more what to expect on the day of examination.
After the examination, normally the medical form was kept at school, it was only if the school doctor had found during the examination a serious issue ( like requirements to wear glasses, or to check the hearing or some heart issues or skin issues or spin curvatures which required remedial gymnastics outside of school) that a letter of the school was send at home to parents.
The letters were always send to parents never to boy's students.
In most of the families, only the mothers did care about all the procedure and read the first letter, the father seemed not to be concerned except I presume for the second leter if thre was a serious issue for the health of their son.