How is yoga useful for preventing headaches?

Sometimes/some types: It can be very useful for preventing some types of headaches of muscular or skeletal/neurologic origin (bones/discs pinching nerves). It can even help relieve existing headaches of these types.For other types of ha's - true migraines, sinus, cluster, for ex., it's not likely to be as helpful. Osteopathic care, including manipulative treatment & preventive care can also help prevent such problems.