Case #3

Case #1

• Acute nondisplaced left parietal bone fracture extending into the left lambdoid suture with mild sutural diastasis
• Subjacent epidural hematoma measuring up to 2 cm in thickness
• Associated mass effect with crowding of the ambient and quadrigeminal cisterns, crowding of the fourth ventricle, and mild upward and downward bulging of the posterior fossa structures without frank herniation
• Small hemorrhagic contusion in the right anterior temporal lobe
• Left parietal scalp hematoma, a portion of which is likely subgaleal, with intermixed locules of gas
• Mucosal thickening of the paranasal sinuses with near complete opacification of the left sphenoid sinus

• Epidural hematoma

• Epidural hematomas represent bleeding between the dura and the inner table of the calvarium
• These are typically arterial, with the middle meningeal artery being the most common offender, but venous epidural hemorrhage is also possible. Here are some common locations for venous epidural hemorrhage:
  • Vertex: fracture and/or sagittal suture diastasis -> superior sagittal sinus injury -> epidural hematoma crossing the suture and inferiorly displacing the sinus
  • Anterior middle cranial fossa: due to hemorrhage from the sphenoparietal sinus, can be managed conservatively
  • Posterior fossa adjacent to an occipital fracture: often related to sinus (especially transverse sinus) injury
• Most are associated with skull fractures
• Epidural hematomas can rapidly expand leading to herniation and death. “Swirling” low density within the hematoma (which is arguably present to some degree in this case) indicates non-clotted fresh blood mixing in with the clotted blood and is concerning for ongoing bleeding
• Epidural hematomas are less common in elderly patients due to increased adherence of the dura to the skull with age
• Epidural hematomas respect suture lines where the periosteal component of the dura extends through the skull. There is one major exception to this: if the suture is disrupted (e.g. if it is diastatic on imaging or if a fracture extends through a suture), then the hematoma can cross suture lines. Notice that the hematoma extends across the diastatic lambdoid suture in this case
• Always look for contrecoup injuries. These are most commonly seen involving the temporal poles and inferior frontal lobes

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