Craniosacral therapy and the pathophysiology of the craniosacral system: Mechanisms, controversies, and proposed future research directions.

Craniosacral therapy (CST) is a non-invasive, alternative therapeutic approach based on the concept of the craniosacral system and its inherent rhythm. This rhythm is a subtle, cyclical expansion and contraction of the dural membranes and cerebrospinal fluid (CSF), which regulates intracranial pressure and the physiological function of the craniosacral system (CS). The CS constitutes a semi-closed, physiological hydraulic network comprising the skull (cranium), the sacrum (tailbone), the associated membranes, and the circulating CSF. Within this system, CSF provides both protection and nourishment to the brain and spinal cord - the body's most vital organs. The craniosacral rhythm (CSR) refers to the physiological rhythm of expansion and contraction within the CS that regulates CSF pressure. Magnetic resonance imaging (MRI) studies have demonstrated the pulsatile nature of intracranial and spinal CSF circulation of approximately 6 to 12 cycles per minute. Experienced CST practitioners palpate this rhythm and assess it for abnormalities that may indicate dysfunction in the fascia, dural membranes, or CSF flow. CST techniques involve gentle manual palpation to release restrictions in dural and fascial structures and restore homeostasis. Some studies suggest that CST may provide therapeutic benefits for a range of conditions, including migraine headaches, non-specific low back pain, depression, anxiety, fibromyalgia, chronic pain, and improved overall quality of life. However, its efficacy for many other conditions remains controversial, and the scientific evidence supporting its physiological mechanisms is limited. This review presents a balanced overview of CST, highlighting its current clinical status, established and hypothesized mechanisms, and emerging directions for future research into both CST and the underlying pathophysiology of the craniosacral system. Notably, recent high-quality basic research has begun to elucidate potential neurophysiological pathways and pathophysiology relevant to CS. For example, new studies have revealed direct anatomical and functional connections between the dura mater and the brain. Furthermore, they demonstrated that in migraine models, trigeminal ganglion neurons are directly activated by CSF influx. Meningeal lymphatic calcitonin gene-related peptide (CGRP) signaling has been implicated in pain induction through CSF efflux and neuroinflammation. These findings opened new avenues for understanding the physiological underpinnings of CST and its potential impact on neural and autonomic regulation.