Subarachnoid

Subarachnoid is a term used in anatomy and medicine to describe a specific space within the human body. This space is located between the arachnoid mater and the pia mater, two of the three membranes, or meninges, that cover the brain and spinal cord. The subarachnoid space is filled with cerebrospinal fluid, which provides cushioning and protection for the brain and spinal cord.

Anatomy

The subarachnoid space is part of the meninges, the three-layered covering of the brain and spinal cord. The outermost layer is the dura mater, followed by the arachnoid mater, and then the pia mater, which is closest to the brain and spinal cord. The space between the arachnoid mater and the pia mater is the subarachnoid space.

Function

The primary function of the subarachnoid space is to provide a cushion for the brain and spinal cord, protecting them from injury. The space is filled with cerebrospinal fluid, which acts as a shock absorber. The subarachnoid space also allows for the exchange of nutrients and waste products between the brain and the cerebrospinal fluid.

Clinical significance

The subarachnoid space is clinically significant because it is involved in several medical conditions. For example, a subarachnoid hemorrhage is a type of stroke that occurs when there is bleeding into the subarachnoid space. This can be caused by a ruptured aneurysm, a head injury, or a brain tumor. Another condition, meningitis, is an inflammation of the meninges that can affect the subarachnoid space.

See also

• Meninges
• Cerebrospinal fluid
• Subarachnoid hemorrhage
• Meningitis