Look here:
View attachment 743645
Intracranial Hematomas Affecting the Skull and Brain
Head injuries can lead to hematomas that affect the brain. Head injuries in sports should always be treated with serious concern that it could result in a traumatic brain injury. Any loss of consciousness, however brief, needs follow-up with a health care provider. If you suspect a head injury but don't see any initial signs or symptoms, you should still follow the head injury first aid treatment steps. Signs for intracranial hematomas include headache, vomiting, drowsiness, dizziness, confusion, slurring of speech and unequal pupil size.
epidural hematoma, also called an extradural hematoma, in which a blood vessel in the head ruptures, often due to a skull fracture, and bleeding occurs between the skull and the brain's protective covering (the dura). This clot can grow either slowly or rapidly and it puts pressure on the brain that, if not treated promptly, can result in coma or death.