Head and Spinal Injury

Head injuries include both injuries to the brain and those to other parts of the head, such as the scalp and skull.

Head injuries may be closed or open. A closed (non-missile) head injury is one in which the skull is not broken. A penetrating head injury occurs when an object pierces the skull and breaches the dura mater. Brain injuries may be diffuse, occurring over a wide area, or focal, located in a small, specific area.

A head injury may cause a skull fracture, which may or may not be associated with injury to the brain. Some patients may have linear or depressed skull fractures.

If intracranial hemorrhage, or bleeding within the brain occurs, a hematoma within the skull can put pressure on the brain. Types of intracranial hematoma include subdural, subarachnoid, extradural, and intraparenchymal hematoma. Craniotomy surgeries are used in these cases to lessen the pressure by draining off blood.

Brain injury can be at the site of impact, but can also be at the opposite side of the skull due to a contrecoup effect (the impact to the head can cause the brain to move within the skull, causing the brain to impact the interior of the skull opposite the head-impact).

If the impact causes the head to move, the injury may be worsened, because the brain may ricochet inside the skull (causing additional impacts), or the brain may stay relatively still (due to inertia) but be hit by the moving skull.

Specific problems after head injury can include:

Skull fracture
Lacerations to the scalp and resulting hemorrhage of the skin
Traumatic subdural hematoma, a bleeding below the dura mater which may develop slowly
Traumatic extradural, or epidural hematoma, bleeding between the dura mater and the skull
Traumatic subarachnoid hemorrhage
Cerebral contusion, a bruise of the brain
Concussion, a temporary loss of function due to trauma
Dementia pugilistica, or "punch-drunk syndrome", caused by repetitive head injuries, for example in boxing or other contact sports
A severe injury may lead to a coma or death

Spinal cord injury causes myelopathy or damage to white matter or myelinated fiber tracts that carry sensation and motor signals to and from the brain. It also damages gray matter in the central part of the spinal, causing segmental losses of interneurons and motoneurons. Spinal cord injury can occur from many causes.