Benjamin Wedro, MD, FACEP, FAAEM
Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
- Head injury introduction
- What are the causes of head injury?
- What are the symptoms of a head injury?
- What is the Glasgow Coma Scale?
- When should I contact a doctor about a head injury?
- How is a head injury diagnosed?
- How is a head injury treated?
- What is the prognosis for a head injury?
- How can a head injury be prevented?
- What about a head injury in infants and young children?
- Head Injury At A Glance
- Patient Comments: Head Injury - Cause
- Find a local Doctor in your town
Head injury introduction
Head injuries are one of the most common causes of death and disability in the United States. Every year, almost a quarter million people are hospitalized because of traumatic injuries to the brain, and 50,000 people die. As well, 80-90,000 people sustain long-term or lifelong disabilities because of a brain injury each year. Children are not excluded, with more than 2,500 deaths and almost a half million emergency department visits per year for head injuries.
Blows to the head most often cause brain injury, it is important to remember that the face and jaw are located in the front of the head. Brain injury may also be associated with injuries to these structures. It is also important to note that a head injury does not always mean that there is also a brain injury.
The brain is a rather soft, pliable material almost jelly-like in feel, and is surrounded by a thin layer of cerebrospinal fluid (CSF). The brain is surrounded by thin layers of tissue called the meninges; 1) the pia mater, 2) the arachnoid mater, and 3) the dura mater. The CSF is present in the space beneath the arachnoid layer called the subarachnoid space.
The dura mater is very thick and has septae, or partitions, that help support the brain in the skull. The septae attach to the inner lining of the bones of the skull. The dura mater also helps support the large veins that return blood from the brain to the heart.
The spaces between the meninges are usually very small but they can fill with blood when trauma occurs, and this build-up of blood can potentially press into the brain tissue and cause damage.
The skull protects the brain from trauma but it does not absorb any of the impact from a blow. Direct blows may cause fractures of the skull; there can be a contusion or bruising and bleeding to the brain tissue directly beneath the injury site. However, the brain can bounce around inside the skull if it is subject to significant force and because of this, the brain injury may not necessarily be located directly below the trauma site. A contre-coup injury describes the situation in which the initial blow causes the brain to bounce and is damaged by hitting the skull directly opposite the trauma site. Acceleration/deceleration and rotation are the common types of forces that can cause injuries away from the area of the skull that received the trauma.
Picture of the brain and potentially brain injury areas
- Epidural hematoma: With an epidural hematoma, the bleeding is located between the dura mater and
the skull. This is often present along the side of the head where the middle
meningeal artery runs in a groove along the
temporal bone. This
bone is relatively thin and offers less protection than other parts of the
skull. As the bleeding continues, the hematoma or clot expands. There is little
space in the skull for the hematoma to grow and as it expands, the adjacent
brain tissue is
compressed. As the pressure increases, the whole brain begins to shift and
becomes compressed against the bones of the skull. The pressure tends to build
quickly because the septae that attach the dura to the skull bones create small
spaces that trap blood. Symptoms of head injury and decreased level of
consciousness occur as the pressure increases.
- Subdural hematoma: A subdural hematoma is located beneath the dura mater
(sub=below), between it and the arachnoid mater. Blood in this space is able to
dissipate into a larger space because there are no septae limiting the blood
flow. However, after a period of time, the amount of bleeding may cause
increased pressure and cause symptoms similar to those seen with an epidural
- Subarachnoid bleed: Subarachnoid bleeding occurs in the space beneath the
arachnoid layer where the CSF is located. Often there is intense
subarachnoid bleeding. Because this space connects with the spinal canal,
pressure build-up tends not to occur. However, this injury often occurs in
combination with the other types of bleeding in the brain, and the symptoms can
- Intracerebral bleed: Intracerebral bleeding occurs within the brain tissue
itself. Sometimes the amount of bleeding is small, but like bruising in any
other part of the body, swelling or
edema may occur over a period of time,
causing a progressive
decrease in the level of consciousness and other symptoms of head injury.
- Sheer injury: Sometimes, the damage is due to sheer injury, where
there is no obvious bleeding in the brain, but instead the nerve fibers within the brain are
stretched or torn. Another term for this type of injury is diffuse axonal
- Edema: All injuries to the brain may also cause swelling or
edema, no different than the swelling that surrounds a
bruise on an arm or leg. However, because the
bones of the skull cannot stretch to accommodate the extra volume caused by
swelling, the pressure increases inside the skull and causes the brain to
compress against the skull.
- Scull fracture: The bones of the skull are classified as flat bones,
meaning that they do not have an inside marrow. It takes a significant amount of force to break the
skull, and the skull does not absorb any of that impact. It is often transmitted
directly to the brain.
Skull fractures are described by which bone is broken, whether there is an associated laceration of the scalp, and whether the bone is depressed and potentially pushed into the brain tissue.
Brain injuries often occur in combination with one another. The effects of brain injury depend upon the amount of brain tissue damaged and the level of pressure within the skull and its effects on the brain.
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