It sounds odd, but the modern discipline of CranioSacral Therapy largely owes its development to a calcium deposit. Dr. John Upledger was assisting another physician in a surgery. Upledger’s job was simple: hold onto the membrane that surrounds the spinal cord as the surgeon removed the calcium growth from its surface.

But the task proved more difficult than anticipated. The membrane kept pulsing at rates that didn’t correspond with the patient’s breathing or heart rate, and it was difficult to hold onto. The pulsations of the membrane confounded Upledger, and he didn’t understand what was causing it until he attended a workshop a few years later. The workshop was on cranial osteopathy, a discipline developed in the early 1900s by Dr. William Sutherland. Sutherland’s theory was that the bones of the skull are structured in a way that allows them to move–not fused together, as many doctors had been taught.

During the workshop, Upledger and other students felt bones to study the way they moved. Many of the students reported feeling a weird rhythm in the bones. Upledger realized this was the same rhythm he had felt during the surgery he’d assisted on years earlier. He eventually came to learn that the pulsation he had felt at the surgery and during the workshop was the movement of the cerebrospinal fluid through the membranes around the brain and spinal cord (also known as the central nervous system).

His discovery during the workshop sparked Upledger to continue studying the area surrounding the central nervous system. Unlike Sutherland, he focused his attention not on bones, but on the fluids and membranes in that region. In 1975, Michigan State University’s College of Osteopathic Medicine asked Upledger to lead a task force to study the movement of bones and joints in the skill. While leading the task force, Upledger and his team explored the craniosacral system and how it affected the rest of the body.

They learned that restrictions in the membranes around the brain and spinal cord can lead to a variety of health problems. They began developing a therapy that could release these tensions with the aim of relieving some the health problems they might be responsible for, such as migraines and chronic neck pain. Upledger coined a name for this new practice: CranioSacral Therapy. Unlike cranial osteopathy, Upledger’s discipline wasn’t just for osteopaths and could be taught to a range of potential practitioners, including massage therapists. The discipline is used all throughout the world today.