A head injury is any trauma to the scalp, skull, or brain. The injury may be only a minor bump on the skull or a serious brain injury.

Head injury can be either closed or open (penetrating).

• A closed head injury means you received a hard blow to the head from striking an object, but the object did not break the skull.
• An open, or penetrating, head injury means you were hit with an object that broke the skull and entered the brain. This is more likely to happen when you move at high speed, such as going through the windshield during a car accident. It can also happen from a gunshot to the head.

Head injuries include:

• Concussion, in which the brain is shaken, is the most common type of traumatic brain injury.
• Scalp wounds.
• Skull fractures.

Head injuries may cause bleeding:

• In the brain tissue
• In the layers that surround the brain (subarachnoid hemorrhage, subdural hematoma, extradural hematoma)

Head injury is a common reason for an emergency room visit. A large number of people who suffer head injuries are children. Traumatic brain injury (TBI) accounts for over 1 in 6 injury-related hospital admissions each year.

Causes

Common causes of head injury include:

• Accidents at home, work, outdoors, or while playing sports
• Falls
• Physical assault
• Traffic accidents

Most of these injuries are minor because the skull protects the brain. Some injuries are severe enough to require a stay in the hospital.