What does a lenticular shape of a hematoma suggest?

The lenticular shape of a hematoma is characteristic of an epidural hematoma. This type of hematoma occurs when there is a tear in the middle meningeal artery, often following a traumatic injury to the skull. The shape is described as lenticular or biconvex because the hematoma forms between the skull and the dura mater, bulging outwards due to the accumulation of blood. The pressure from the expanding hematoma can cause significant brain injury and lead to a rapid deterioration of the patient's condition.

In contrast, a subdural hematoma has a crescent shape, as it forms between the dura mater and the brain due to tearing of the bridging veins, typically following more diffuse or shearing type injuries. Understanding the shapes associated with different types of hematomas is crucial for diagnosis and management in critical care settings.