Proxemics - the study of intimate environments
The term 'proxemics' was invented by an anthropologist, Edward T Hall, to describe the emotional and social meaning of the otherwise invisible boundaries that people implicitly have around them.
Though varying significantly between cultures - Hall was an anthropologist, and therefore already attuned to the differences in such contexts - there are such boundaries, Hall suggested in all cultures, and the meaning of entering or respecting them is much the same in all.
Hall, as an anthropologist, was thinking here of different cultures in terms of different nations, or whole populations. In practice, within nations and sub-groups, and in particular within services, there are different cultures, in which there may be different calibrations of intimacy or distance.
In a healthcare environment, for example, some physical touching may need permission, but it is expected and permission is more readily given. In a courtroom, a degree of distance between people in different roles is established and standardised by the layout of the courtroom itself, and re-enforced by the mannered language of the process.