Intralaminar dural hemorrhage

Intralaminar dural hematomas in the intracranial space, are exceedingly rare, and represent hemorrhage between the two layers of the dura mater. As a result, it has distinctive features allowing it to be distinguished from extradural hematomas but mimics subdural hematomas. They are equivalent to epidural hematomas of the spine.

Pathology

The hematoma occurs within the extradural neural axis compartment, located between the visceral layer (true dura or dura propria) and the parietal layer (cranial periosteum) and as such is actually in the same compartment as spinal epidural hematomas (rather than extradural hematomas that represent subperiosteal hematomas on the inside of the skull). 

Radiographic features

Unlike extradural hematomas, intralaminar hematomas are not confined by sutures but extend to the dural venous sinuses as they are within the same space as the sinuses. 

Unless a subdural hematoma is also present, they can be difficult to separate from true subdural hematomas (which occur between the arachnoid mater and the inner layer of the dura), as both will cross sutures, but be confined by dural sinuses.