The brain and spinal cord are protected from environmental influences not only by the bone structures that surround them (the skull and spine, respectively), but also by the membranes. In total there are three shells, between which there are cavities, or spaces. More on these structures later in the article.
Sheaths of the brain
To understand how the spaces between the membranes of the brain, including the subdural space, are arranged, one should know what membranes generally surround the brain tissue.
If you follow from outside to inside, you can distinguish the following meninges:
- hard;
- spider web;
- soft.
Moreover, they are identical for both the brain and the spinal cord. The membranes in the spinal cord are, in fact, a continuation of the brain.
The hard shell is the outermost. It covers all brain structures in the form of a bag, but does not adhere tightly to the bones of the skull and vertebrae. Between it and the bone structures there is still a periosteum.
The gossamer is in the middle. It looks like a thin sheet that is not saturated with vessels. Many crossbars extend from it to the hard shell, penetrating the entire space between these two structures.
The soft shell is directly adjacent to the brain or spinal cord. It consists of two sheets, between which there is a large number of vascular elements. Surrounding these vessels are lymphatic spaces in which lymph circulates.
Epidural space
Between the dura mater and bone structures is the epidural space. It is filled with adipose tissue and vascular plexuses. At the level of transition of the spinal cord to the brainstem, the dura fuses with the foramen magnum of the occipital bone, and the epidural space of the spinal cord passes into the same space, only around the cerebrum.
Subdural space
If the epidural cavity is located above the dura mater, then the subdural cavity is located below it. Thus, the subdural space lies between the dura mater and the arachnoid mater. It looks like a narrow gap filled with a small amount of CSF (cerebrospinal fluid).
Subdural hematomas
The accumulation of blood in the subdural space is called subdural hematomas. The main reason is traumatic brain injury. Moreover, the accumulation of blood between the membranes of the brainoccurs much more frequently than in the dorsal.
Hematoma in the subdural space can occur at any age. According to statistics, most often the following incidents lead to its development:
- accidental childhood trauma;
- traffic accidents among young people;
- falling from height in the elderly.
When traumatizing the head in 15% of cases, blood accumulates in the subdural space of the brain. If he talks about fatal head injuries, then a hematoma is present in 30% of cases.
Clinical picture
The accumulation of blood in the spaces between the shells leads to an increase in pressure inside the cranium and compression of the brain tissue. The larger the hematoma, the more severe the clinical manifestations. Most patients have the following symptoms:
- impaired consciousness by type of stupor, stupor or coma;
- increased pupil on the side of the lesion;
- violation of the pupillary reflex;
- presence of focal neurological symptoms (determined by a neurologist during the examination of the patient).
With extensive hematomas or delay in seeking clinical care, swelling and displacement of the brain increase. This leads to pinching of the medulla oblongata, which contains important centers for breathing and heartbeat. As a result, cardiac or respiratory arrest is possible.
But a hematoma can be not only in the brain. It is possible to accumulate blood in the subdural space of the spinal cord when ittraumatization. Spinal fractures are often the cause. In this case, the following clinical manifestations are possible:
- violation of sensitivity below the level of the lesion (hypesthesia) or its complete absence (anesthesia);
- weakness of the limbs (paresis) or complete immobilization (paralysis);
- possible disruption of the pelvic organs (urinary retention or incontinence).
Diagnostic Methods
If an epidural hematoma is suspected, additional examination methods should be carried out as soon as possible. Time plays a very important role here, especially when it comes to intracranial hematoma. In this case, hematomas are most often found in the middle cranial fossa and at the top in the fronto-parietal region.
Computed tomography (CT) is usually enough to make a definitive diagnosis. This is an X-ray diagnostic method that allows you to accurately see the bone and meningeal structures of the brain, visualizes the vertebrae, epidural and subdural spaces of the spinal cord. In addition, CT is very good at showing blood accumulation. Therefore, for the diagnosis of hematomas, this method has practically no equal.
In the absence of a CT scan, an x-ray of the skull or spine can be taken. But, of course, the diagnostic value of this method is much lower.
Conclusion
The accumulation of blood in the subdural space is a serious problem that needs to be diagnosed and surgically corrected as soon as possible.intervention. Since the spaces between the membranes of the brain are very narrow and pliable, the blood that collects in them quickly leads to damage to the brain structures.
But it is important to remember that there are pathologies that can mimic a subdural hematoma. Therefore, they must be taken into account when making a diagnosis:
- an increase in the size of the subdural spaces due to brain atrophy;
- subdural empyema - accumulation of pus between the hard and arachnoid membranes of the brain or spinal cord;
- epidural hematoma - accumulation of blood between the hard shell and the periosteum;
- subdural hygroma - accumulation of fluid between the arachnoid and hard shells.
