The dura mater (from medieval Latin dura mater cerebri, meaning “the hard mother of the brain”) constitutes one of the structures of the meninges, themselves located in the central nervous system.

Position. The dura is one of the three layers of the meninges. The latter are made up of connective membranes enveloping the central nervous system: the brain and the spinal cord (1).

Dura mater structure. Composed of dense connective tissue, the dura is the most resistant and outermost membrane of the meninges. It can be distinguished into two parts (1) (2) (3):

• The cranial dura mater is located at the level of the brain and consists of two layers (2):

  – the external layer, attached to the internal face of the cranial box, is present only at the level of the encephalon;

  – the internal layer, enveloping the brain, extends within the spine to surround the spinal cord.

  These two leaflets are welded together, except at certain points such as on the median plane of the brain where the internal leaflet detaches to form the scythe of the brain, covering the two cerebral hemispheres. An upper cavity is thus formed and corresponds to the sinus of the dura mater, which collects venous blood

• The spinal dura is located at the level of the spinal cord. The inner layer of the dura mater is attached to the foramen magnum, a cavity located under the skull, and extends to form a sac surrounding the spinal cord, the dural sac. At the level of the latter, the dura is pierced by the spinal nerves. The end of the dural sac is anchored at the level of the coccyx thanks to the terminal filum (3).

The dura mater thus constitutes the membrane closest to the vertebrae. It is separated from the latter by the epidural, extradural or epidural space, containing adipose tissue and blood vessels.

Protective role. Given its position and structure, the dura helps protect the brain and spinal cord.

Trauma. Impacts to the skull or spine can cause damage, especially to the dura (4). Brain lesions can be concussions, that is, reversible lesions, or bruises, which are irreversible lesions (3).

Brain tumors. Benign or malignant tumors can develop in the meninges, especially in the dura (5).

Meningitis. This pathology corresponds to an inflammation of the meninges, occurring at the level of the brain, the spinal cord or jointly at the level of the two sites. The causes of this pathology are varied and may in particular be of bacterial or viral origin. Meningitis can cause headaches, neck stiffness or fever (1).

Drug treatments. Depending on the pathology diagnosed, certain medications may be prescribed such as anti-inflammatory drugs or antibiotics.

Surgical treatment. Depending on the type of pathology diagnosed and the course, a surgical operation may be carried out.

Spinal anesthesia. This anesthesia consists of injecting an anesthetic into the subarachnoid space, located between the arachnoid and the pia mater. This anesthesia makes the lower part of the body numb.

Epidural anesthesia. This anesthesia consists of injecting an anesthetic into the epidural space, located between the dura and the spine. Commonly used during childbirth, this anesthesia makes the lower abdomen numb.

Chemotherapy, radiotherapy. Depending on the type and stage of the tumor, these treatments may be used to destroy cancer cells.

Physical examination. First, a clinical examination is performed to assess the symptoms perceived by the patient.

Medical imaging exam. In order to assess damage to the dura mater, a cerebral and spinal CT scan or a cerebral MRI can in particular be performed.

biopsy. This examination consists of a sample of cells.

Lumbar puncture. This exam allows the cerebrospinal fluid to be analyzed.

Allowing to suggest the presence of a meningeal syndrome, the sign of Kernig was described by the Russian doctor Wladimir Kernig in the XIXth century. Positioned on the back, thighs bent towards the pelvis, the patient must keep the legs straight. Kernig’s sign is seen if the patient is unable to perform this movement due to pain forcing him to bend the knees (1). This sign is often associated with stiffness in the neck.