Craniosacral therapy was developed in the late 19th century by William Garner Sutherland who believed that the bones of the skull were capable of subtle movement, in contrast to accepted anatomical views. John Upledger later expanded on Sutherland's work in the 1970s. Craniosacral therapy involves gentle palpation to detect and manipulate the cranial bones and release restrictions in the craniosacral system to support health and healing. While some research studies show promise for reducing migraine symptoms, the subtle and variable nature of craniosacral therapy makes it difficult to study and research results are mixed.