What can you see
The study shows spondylolisthesis - sliding of the vertebra forward or backward, decreased disc height, spondyloarthrosis, developmental anomalies (sacralization, lumbarization), consequences of injuries and signs of osteoporosis. This is the standard initial investigation for low back pain. If the pain radiates down the leg and there is a suspicion of a disc herniation, an X-ray is usually followed by an MRI - the herniation itself is not shown on the image.
What X-rays show and what they don't show
An X-ray image perfectly visualizes bone tissue: fractures, cracks, displacements, changes in joint spaces, bone growths, bone destruction. That is why it remains the first method for injury and pain in the joints and spine.
Soft tissues - ligaments, menisci, discs, cartilage - are practically invisible in the image. If the doctor suspects damage to these structures, an MRI is prescribed after the x-ray. X-rays are not “worse” than tomography: they are different tools for different tasks.
Why is the photo taken in two projections?
One projection gives a flat image, and a fracture without displacement or located at a certain angle may not be visible on it. The second image, taken perpendicular to the first, allows you to evaluate the object in a different plane. The standard for bones and joints is precisely two projections; studies in one projection are used as screening or when the patient’s position is limited.
What are functional tests
A typical spine scan is taken in a neutral position and shows a static picture. Functional tests - photographs in maximum flexion and extension - reveal instability: excessive mobility of the vertebrae relative to each other, which cannot be seen at rest. This study is prescribed for chronic pain, after injuries and before spinal surgery.
About radiation exposure
The dose for digital radiography is significantly lower than for film radiography, and for most studies is comparable to several days of natural background radiation. Nevertheless, the principle of validity remains: the study is performed as prescribed by the doctor. During pregnancy, X-rays are performed only for health reasons with screening.