Common Skull Fractures

Skull fractures a diagnosed by their location, type and associated signs.

The bony skull surrounding the brain is on average about a quarter of an inch thick. In order for the skull to break, it has to be hit with a powerful force, so skull fractures are always considered a serious sign of head trauma. 

Skull fractures are classified as open head injuries since there is now an opening through the skull bone that can potentially lead directly to the brain. Skull fractures may be diagnosed by where they occur, or by the physical signs that indicate they have happened.

Basilar Skull Fracture

The base of the skull is at the back of the head, and surrounds the area through which the spinal cord attaches to the base of the brain. A basilar skull fracture often includes the occipital bone at the back of the skull, and the temporal bones on the sides of the skull. It can also extend into the bones around the nose and eyes.

A basilar skull fracture may be associated with Battle’s Sign and Raccoon Eyes.

Battle’s Sign: There is a bony prominence behind the ear called the mastoid process. If there is bruising over this bone, behind the ear and even extending down the side of the neck, this is considered a Battle’s Sign. It can take about a day for the sign to show up.

If there is a fracture in this area, there may be associated hearing loss due to nerve damage. Cerebrospinal fluid, which is a clear watery liquid when normal, or yellowish and sticky when infected or blood is present, may leak out of the ear.

Raccoon Eyes: Bleeding from a fractured skull, travels under the soft tissues and collects in certain areas of least resistance. One of these areas is under the eyes. Raccoon eyes are dark, bruised circles that appear under both eyes. This sign may take a few days to show up after a skull fracture, as blood seeps into and through the cranial sinuses.

Compound Skull Fracture

In a compound fracture, there are broken bones and torn tissues that enable outside organisms such as bacteria and parasites, to have a pathway to the brain.

Compound fractures include tears to the scalp, broken bones of the skull, sinuses or ears, and tears to the protective meningeal layer of tissues that directly surround the brain. Compound fractures often require surgical repair of the bones and tissues.

Depressed Skull Fracture

When the skull is hit by a powerful force it can either crack and spread apart, or the blow can push the bones inward. In a depressed skull fracture the bones are pushed inward, in the direction of the brain. Sometimes bone fragments pierce through the brain’s covering and into the brain itself.

Broken bones have to be carefully removed by a neurosurgeon, and the skull reconstructed. A depressed skull fracture can also be a compound fracture, if it is deep and traumatic enough.

Diastatic Skull Fractures

The skull is not one continuous piece of bone, but rather individual pieces of bone that fuse together along suture lines.

The skull bones bond together and harden into one connected piece of bone throughout childhood and into adulthood. These suture lines are not as strong as other parts of the skull.

If there is head trauma during infancy and childhood, fractures are usually seen along these lines. Sometimes, if the skull is still hardening, this also allows the brain to swell after trauma, lessening the overall pressure inside the skull.

Linear Skull Fractures

A linear skull fracture can be described as a crack in the skull. It extends through the full thickness of the skull bone, but there is no overall change in structure of the cranium. The brain may still be protected by the surrounding tissues.  

Sources

Zilinskiene, L., Idle, M. R., & Colley, S. (2014). Emergency radiology: Maxillofacial and skull-base trauma. Trauma, 16(4), 243-255. doi:10.1177/1460408614539619

Continue Reading