page_title: Subdural hematoma
section_title: Diagnosis
hierarchical_section_title: Subdural hematoma / Diagnosis
caption_attribution_description: Čeština: Subdurální hematom na CT English: Ct-scan of the brain with an subdural hematoma Nederlands: Ct-scan van de hersenen met een sub-duraal hematoom
context_page_description: A subdural hematoma is a type of bleeding in which a collection of blood—usually associated with a traumatic brain injury—gathers between the inner layer of the dura mater and the arachnoid mater of the meninges surrounding the brain. It usually results from tears in bridging veins that cross the subdural space.
  Subdural hematomas may cause an increase in the pressure inside the skull, which in turn can cause compression of and damage to delicate brain tissue. Acute subdural hematomas are often life-threatening. Chronic subdural hematomas have a better prognosis if properly managed.
  In contrast, epidural hematomas are usually caused by tears in arteries, resulting in a build-up of blood between the dura mater and the skull. The third type of brain hemorrhage, known as a subarachnoid hemorrhage, causes bleeding into the subarachnoid space between the arachnoid mater and the pia mater.
context_section_description: It is important that a person receive medical assessment, including a complete neurological examination, after any head trauma. A CT scan or MRI scan will usually detect significant subdural hematomas.
  Subdural hematomas occur most often around the tops and sides of the frontal and parietal lobes. They also occur in the posterior cranial fossa, and near the falx cerebri and tentorium cerebelli. Unlike epidural hematomas, which cannot expand past the sutures of the skull, subdural hematomas can expand along the inside of the skull, creating a concave shape that follows the curve of the brain, stopping only at dural reflections like the tentorium cerebelli and falx cerebri.
  On a CT scan, subdural hematomas are classically crescent-shaped, with a concave surface away from the skull. However, they can have a convex appearance, especially in the early stages of bleeding. This may cause difficulty in distinguishing between subdural and epidural hemorrhages. A more reliable indicator of subdural hemorrhage is its involvement of a larger portion of the cerebral hemisphere. Subdural blood can also be seen as a layering density along the tentorium cerebelli. This can be a chronic, stable process, since the feeding system is low-pressure. In such cases, subtle signs of bleeding—such as effacement of sulci or medial displacement of the junction between gray matter and white matter—may be apparent.
  Fresh subdural bleeding is hyperdense, but becomes more hypodense over time due to dissolution of cellular elements. After 3–14 days, the bleeding becomes isodense with brain tissue and may therefore be missed. Subsequently, it will become more hypodense than brain tissue.
caption: A subdural hematoma demonstrated by CT
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