Extradural hematoma refers to accumulation of blood between skull bone and the dura mater. It appears as biconvex hyperintense lesion on CT scan. Subdural hematoma refers to bleeding between dura and arachnoid mater. On CT, the condition is identified as 'banana-shaped' hyperintense concave lesion. Reference: https://radiopaedia.org/cases/extradural-vs-subdural-haematoma-lemon-vs-banana Image via: https://radiopaedia.org/cases/extradural-vs-subdural-haematoma-lemon-vs-banana