A 20-year-old man is brought to the emergency room after bei…

A 20-year-old man is brought to the emergency room after being struck in the temporal region with a baseball bat. He briefly lost consciousness, then regained alertness, but later became lethargic. CT imaging reveals a biconvex (lens-shaped) hyperdensity between the skull and dura mater. What type of traumatic brain injury is most likely, and which vessel is commonly involved?