Wrist . Stems from chinese acupuncture which these points or meridians are believed to be organ associated. And it works!
Homeopathy Tabacum. Yes there are pressure points on the wrist to prevent motion sickness as has been answered. There is a fabulous homeopathic remedy that works wonders. It is tabacum. 30c 2 pellets as needed. I recommend it all the time for cruises or anytime one has to travel and gets motion sickness.
Possibly. Some of my patients have had som relief from bands that apply pressure to point on the wrists. I can't say scientifically how they work but these patients do tell me they help.