Dura mater which is the outer most layer, Arachnoid which is the middle one and Pia mater which is the inner most. The infections of meninges are known as meningitis. Meninges are layers made up of connective tissues which perform a variety of functions which will be discussed later in this paper.
Dura is a Latin word which means ‘hard mother’. Dura mater is the outer most of the meningial layers. As the name indicates it is rigid and nonflexible. It separates the brain from the cranial cavity and also prevents the brain from translocation. It is a double layered structure consisting of connective tissues. The outer layer of Dura matter is called the periosteal layer which is attached to the bones of the cranium. The inner layer is much soft and thinner and is called the meningeal layer. It holds on to the brain but does not attach itself to the bone. Along the spinal cord it is a single membrane but is similar to the cranial meninges.
Dura mater is a fused membrane except at some regions where it is quite separate and possesses an appropriate lining. These separations allow the Dura membrane to cover the dural sinuses. These sinuses are accountable for the collection of blood in veins which is further collected into a single vein in the neck region. There are four distinct regions where dura membrane segregates. The superior sagittal sinus runs across the top of the brain in an anterior-posterior direction. Other sinuses are the straight sinus, the inferior sinus, and the transverse sinus. Dura mater covers the spinal cord in tubular form. It is quite thick and wraps the whole spinal cord up to its end. There is a space between dura mater and skull known as the epidural space. In case of any hemorrhage in the brain or any closed injury, blood is collected in this epidural space. There is also a potential space between dura mater and the middle layer of meninges called arachnoid which is known as the subdural space. In case of any shock