The subdural space is an artificial space created by the separation of the arachnoid mater

Arachnoid mater

The arachnoid mater, literally from Latin "spider -like mother", is one of the three meninges, the membranes that cover the brain and spinal cord...

 from the dura mater

Dura mater

The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...

 as the result of trauma, pathologic process, or the absence of cerebrospinal fluid

Cerebrospinal fluid

Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...

 as seen in a cadaver. In the cadaver

Cadaver

A cadaver is a dead human body.Cadaver may also refer to:* Cadaver tomb, tomb featuring an effigy in the form of a decomposing body* Cadaver , a video game* cadaver A command-line WebDAV client for Unix....

, due to the absence of cerebrospinal fluid, the arachnoid mater falls away from the dura mater. It may also be the site of trauma, such as a subdural hematoma

Subdural hematoma

A subdural hematoma or subdural haematoma , also known as a subdural haemorrhage , is a type of haematoma, a form of traumatic brain injury. Blood gathers within the outermost meningeal layer, between the dura mater, which adheres to the skull, and the arachnoid mater, which envelops the brain...

, causing abnormal separation of dura and arachnoid mater. Hence, the subdural space is referred to as "potential" or "artificial"

Potential space

In anatomy, potential space refers to a space or cavity that can exist because two adjacent features that are not tightly adjoined, but does not appear during normal functioning.-Examples:* subdural space* vagina* pericardial cavity...

space.