The use of pressure points and hitting vital points has been a part of combat since prehistoric times. This is obvious from the study of isolated tribal people who live similarly to prehistoric people; like the Aleuts (or as they call themselves the Unangan, which means "the people" in their language). The Aleuts are a tribal people that inhabit the islands called the Aleutian Islands (about 1,800 km southwestward from the Alaskan mainland). They have a martial arts style derived from watching animals fight, particularly sea-lions and dogs. In their observations they noticed that the animals will attack particularly vulnerable parts of the body.
Both Chinese and Japanese martial arts make use of vital spots/pressure points. Ranma in the manga occasionally makes use of these types of attacks, for example the fight with Kuno or the fight versus the Dojo Destroyer. Takahashi is not a martial artist and does not have Ranma use the actual vulnerable spots (nerve clusters, organs, etc.), instead uses places considered to be them in popular culture/chosen at random and then have him or another character state he hit them.
A story in which Ranma fights human characters would likely have him use these types of attacks occasionally. While there are many attacks Ranma is unlikely to do, since he doesn't want to maim or kill his opponents, there are many he would be expected to use or prevent his opponent from hitting. It would be out of character for Ranma to do attacks like a finger gouge to the eyes, hit the mastoid process (which could cause loss of motor control or paralysis), or rabbit punch someone to the base of the skull (could damage the cervical vertebra causing paralysis or death). Ranma in all likelihood has a lot of knowledge on human anatomy (kind of needs to so as to not hurt his opponents, even if he doesn't know the scientific names for the body parts, additionally supported since Ranma can be seen reading these types of charts in the manga -example Miss Hinako intro arc). The thing is I have no idea as to how a writer would convey the use of these types of attacks in literature. Too detailed will likely just annoy readers. Writing it like this: "Ranma did a quick jab to the brachioradialis muscle in the upper lateral forearm temporarily paralyzing Ryoga's arm." Is probably not the way to go about it. This is in part why I dislike and haven't posted any story I attempted to write, I really don't know how to write a fight scene (there are other reasons as well).
Though Ranma is also likely to use foot reflexology is called Zoku Shin Do, massage (offers one to Nabiki, gives one to Akane to calm her down, gives Rouge the Ashura one during battle), chiropractics (Ranma is shown reading a book on it), Acupuncture, Moxibiton, etc. outside of battle as well such as healing ones or for pleasure.