The Craniosacral System
The spinal cord is surrounded by a protective, three-layered membrane system (the meninges) that lies within the vertebral column. The outside layer is called the dura mater; the middle layer the arachnoid membrane; and the innermost layer the pia mater. The inside layer is tightly attached to the spinal cord, while cerebrospinal fluid is between the other sections. In addition to providing nutrients, the lubricating cerebrospinal fluid allows the membrane layers to glide in relationship to one another as the spine bends and twists. The tough dura mater protects everything inside of it, including the brain and spinal cord.
The craniosacral system consists of this membrane system, the enclosed cerebrospinal fluid, related bones, and the physiological structures that control fluid input and outflow. It is a semi-enclosed biological hydraulic system encompassing the brain and spinal cord. Within the system, the cerebrospinal fluid rhythmically pulses at a rate of about ten cycles per minute. This is independent of heart or respiratory rhythms.
The craniosacral system’s fluid barrier is the dura mater, which also composes the skull’s inside lining. Research indicates that the skull bones must be slightly moving continuously to accommodate the fluid pressure changes within this semi-closed hydraulic system. The membrane barrier is also attached to the upper neck vertebrae, the lower back sacrum, the tailbone, and the openings in the spinal column where nerves go out to the body.
Craniosacral therapy’s object is to find areas of restricted movement that compromise function and re-establish normal movement. Because the craniosacral system encloses the brain and spinal cord, it influences the entire nervous system, affecting many body functions. These include the brain’s important pituitary and pineal glands. These glands, in turn, have the potential to affect the body’s entire hormonal balance.