The meninges enclose the brain and spinal cord (CNS) as one unit like a tightly fitting stocking. There are three layers of meninges, called the dura mater, arachnoid mater, and pia mater.
The dura mater is the most outer layer, very tough, and lines the inside of the skull, as well as attaches to the first two neck vertebrae, and the sacrum, The arachnoid mater is the middle layer and adheres to the dura mater. It also has weblike attachments to the innermost layer, the pia mater. The pia mater is very thin, transparent, but tough, and covers the entire brain, following it into all its crevices (sulci). Because of these intimate connections between these three layers, any trauma from the outside of the skull, or from within the skull, such as bleeding in or around the brain, tumors, infections, or hydrocephalus, will be transmitted to all layers.
The dura mater, a very tough membrane, divides the inside of the skull into three main compartments:
an upper one (two rooms) which houses the two hemispheres, and a lower one, which contains the cerebellum. The two rooms upstairs are created as the dura separates the cerebral cortex into the two hemispheres. This portion of the dura is called the FALX CEREBRI. The dura also supports the two hemispheres by forming a tent-like structure , the TENTORIUM, above the cerebellum. Thus, the dura separates the cerebral cortex from the cerebellum. Moreover, the dura partially divides the cerebellum into two hemispheres. This structure is the FALX CEREBELLI. A pretty complicated but elegant affair.
Distortion of the meninges can affect your body’s hormonal functions and balance.
Another fact often overlooked: the tentorium covers the sella turcica (an indentation of the sphenoid bone), which houses the pituitary gland. This gland, called the master gland, controls all hormonal actions in the body. Trauma to the head may distort this part of the tentorium and thus exert pressure on the pituitary gland, potentially resulting in a variety of hormonal disturbances, including menstrual irregularities and associated pain/discomfort.
This three-layered meningeal system contains not only the brain and spinal cord but also the most important cerebrospinal fluid (CSF).
The cerebrospinal fluid, which buffers, nourishes, and detoxifies the brain and spinal cord, flows through the subarachnoid space, between the arachnoid mater and the pia mater. The smooth flow of this fluid, or lack thereof, can dramatically affect one’s health.
In the next post, we explore the form and function of cerebrospinal fluid.