X-rays of the Skull

By Sara Foster

(Skull X-ray Studies)

Procedure overview

What are X-rays of the skull?

X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film. Standard X-rays are performed for many reasons, including diagnosing tumors or bone injuries.

X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body tissues onto specially treated plates (similar to camera film) and a "negative" type picture is made (the more solid a structure is, the whiter it appears on the film).

When the body undergoes X-rays, different parts of the body allow varying amounts of the X-ray beams to pass through. Images are produced in degrees of light and dark, depending on the amount of X-rays that penetrate the tissues. The soft tissues in the body (such as blood, skin, fat, and muscle) allow most of the X-ray to pass through and appear dark gray on the film. A bone or a tumor, which is denser than the soft tissues, allows few of the X-rays to pass through and appears white on the X-ray. At a break in a bone, the X-ray beam passes through the broken area and appears as a dark line in the white bone.

While X-rays of the skull are not used as often as in the past, due to the use of newer technologies such as computed tomography (CT scans) and magnetic resonance imaging (MRI), they remain valuable for evaluating the bones of the skull for fractures and detecting other conditions of the skull and brain.

In addition to CT scans and MRI, other related procedures that may be used to diagnose problems involving the skull and/or brain include positron emission tomography (PET) and bone scan. Please see these procedures for additional information.

Bones of the skull

The skull, also called the cranium, is the bony structure of the head. Two sets of bones comprise the skull:

  • Cranial bones. Bones that protect and enclose the brain.

  • Facial bones. Bones that provide the framework for the face and mouth.

All bones comprising the skull are attached to each other via immovable joints, except for the mandible, which is attached via a movable joint.

The cranium, which holds and protects the brain, consists of eight bones (frontal bone, parietal bones, temporal bones, ethmoid bone, sphenoid bone, and occipital bone). The skeleton of the face has 14 bones, which include those that make up the jaws, cheeks, and nasal area.

Reasons for the procedure

X-rays of the skull may be performed to diagnose fractures of the bones of the skull, congenital anomalies (birth defects), pituitary tumors, and certain metabolic and endocrine disorders that cause bone defects of the skull. Skull X-rays may also be used to detect tumors, evaluate the nasal sinuses, and detect cerebral calcification (calcifications within the brain).

There may be other reasons for your physician to recommend an X-ray of the skull.

Risks of the procedure

You may want to ask your physician about the amount of radiation used during the procedure and the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure, such as previous scans and other types of X-rays, so that you can inform your physician. Risks associated with radiation exposure may be related to the cumulative number of X-ray examinations and/or treatments over a long period of time.

If you are pregnant or suspect that you may be pregnant, you should notify your physician. Radiation exposure during pregnancy may lead to birth defects. If it is necessary for you to have a skull X-ray, special precautions will be made to minimize the radiation exposure to the fetus.

There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.

Before the procedure

  • Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.

  • Generally, no prior preparation, such as fasting or sedation, is required.

  • Notify the radiologic technologist if you are pregnant or suspect you may be pregnant.

  • Notify the radiologic technologist if you have a prosthetic (artificial) eye, because the prosthesis can create a confusing shadow on an X-ray of the skull.

  • Based upon your medical condition, your physician may request other specific preparation.