Using an X-Ray to Diagnose Back Pain

Medical X-rays (a form of medical radiography) have been an important diagnostic tool since their discovery in 1895. An X-ray is an imaging test that allows a physician to look at bony structures inside a patient’s body without surgery. The obvious benefit of this is that X-rays minimize the risk involved in the diagnostic process by eliminating the need for invasive exploratory surgery.

X-ray testing is often ordered by physicians trying to diagnose back pain. X-rays can show the condition and alignment of vertebrae, helping physicians look for fractures, weaknesses and dislocations. An X-ray is generally the first imaging test a physician will order before moving on to more advanced forms of radiography, such as MRIs, CT scans, or bone scans.

How X-rays work

An X-ray is a form of electromagnetic radiation that, when passed through an object, creates shadows of the structures within that object. X-rays pass through light molecular weight atoms like hydrogen, carbon, nitrogen and oxygen. These atoms make up skin, muscles and other soft tissues. Heavier molecular weight atoms such as calcium and iron (those found in bones and metal) block X-rays. Thus, when X-rays shine on the body, some are transmitted and some are blocked. X-rays can develop photographic emulsions. The X-rays studied by physicians and seen by patients are a piece of acetate film covered with photographic silver emulsion. The “picture” seen is actually a shadow-gram of the bones within the patient.

X-rays are taken by having the patient lie underneath a device that emits radiation. If possible, the X-ray technician will cover vital organs outside the area to be diagnosed with a lead apron to minimize the exposure to radiation, which can be harmful over time. The X-ray device is aimed at the area of the body to be imaged, and then the X-rays are passed through. The X-ray tech then captures the resulting images on a large piece of film, which is then developed and given to the physician for review.

The role of X-Rays in diagnosing back pain

X-rays are useful for viewing vertebrae that may be affected by the following:

  • Arthritis of the spine
  • Bone spurs
  • Spondylolisthesis
  • Fractures
  • Tumors

Since the X-rays penetrate through soft tissue and do not capture them on film, they typically will not show herniated discs, bulging discs, sciatica, pinched nerves or disorders involving the spinal cord. To clearly see soft tissue problems, physicians may order an MRI, CT scan, myelogram, or other more advanced imagery.