In an epidural bleeding in the head, blood pours into the space between the skull bone and the outermost meninges, the dura mater. It can also be called an epidural hematoma because it is a bruise (haematoma) in the epidural space. The epidural space also exists in the spinal column, between the spinal canal and the dura mater, but epidural bleeding is much more common intracranially (in the head) than spinally (in the spinal column).
The meninges are composed of three layers: the pia mater lies directly on the brain tissue and encloses it also in its furrows (sulcus), the arachnoidea mater is located in the middle and lies superficially on the brain as a whole, and the dura mater is firmly connected to the skull bone and forms the outer shell. In the spinal column, fatty tissue is located in the epidural space – only in a few places is the dura mater fused with bone. The function of the meninges is to protect and stabilize the brain, as well as to separate the cerebrospinal fluid (liquor) from the neuronal tissue. Bleeding, whether arterial or venous, is usually caused traumatically, i.e. by an accident. Any bleeding in the head is an injury that requires urgent treatment, as life-threatening conditions can develop.
Causes of epidural bleeding
An epidural hemorrhage is usually related to a craniocerebral trauma, which is usually caused by an accident. The most common circumstances are car accidents, as the head is often injured by the impact and a fracture of the skull bone can occur. There are two different types of bleeding: arterial and venous bleeding.
The arterial bleeding usually comes from the artery that supplies the meninges – the arteria meningea media (from the arteria maxillaris, a branch of the arteria carotis externa). It occurs more frequently than venous bleeding and is associated with a greater blood flow. In most cases, the epidural hematoma develops in the area of the temporal lobe, on the side of the brain.
In the case of a venous hematoma, the blood seeps into the resulting fracture gap. This is more likely to be observed in children and the clinical picture develops only very slowly, since torn veins do not bleed as much. A spinal epidural hemorrhage can have other causes besides traumatic events. Malformations of the vascular system in or around the spinal cord, tumors or problems of the coagulation system can promote an epidural hematoma. The coagulation system can be affected by genetic defects or diseases, for example, but also by treatment with blood thinners (anticoagulants).
