So for a low back test, for the first image bend forward to touch your toes. This may require you to stick to your guns and insist you drive the amount of movement needed. The trick to this test is to softly ignore the instructions of the radiology tech and get as much flexion (bending forward) and extension (bending backwards) as possible. However, if there’s not enough motion, the test can be a “false negative.” This means that instability may be present, but the test will miss it. In addition, having the patient get the needed motion may be more technically difficult for the tech. Hence, they learn over time that pushing patients to their limit on this test is not advisable. Radiology techs get in trouble if a patient reports that this test flared up their pain. In fact, most of the time they do it wrong. In a perfect world, the technologists taking these images would perform each one with enough movement to show if any instability is present. The Problem With Flexion-Extension X-Rays For the neck, the patient looks down and then up. For the low back, the patient is asked to bend forward and then backwards while x-ray images are taken in both positions. This is called a flexion-extension x-ray. In order to replicate the conditions under which there is too much movement in the spine vertebrae, an x-ray can be taken when the patient moves. Hence, many patients who have normal or unimpressive x-rays or MRIs are later diagnosed with instability as the cause of their back or neck pain. Since regular x-rays and MRIs are static images without any movement, these tests can’t identify instability, which happens only with movement (2). Can Instability Be Seen on an X-Ray or MRI? By submitting the form you agree that you've read and consent to our Privacy Policy. We do not sell, or share your information to third party vendors. In fact, sometimes the spine looks fine on MRI when the real culprit is instability. This is a big deal, as unstable vertebrae can cause pain by placing excessive wear and tear on the spine joints (facets) or disc, and can irritate or pinch the spinal nerves leading to nerve pain or sciatica. If the ligaments get injured or the muscles go off line, the vertebrae can move too much, leading to too much motion between them, or an unstable spine (1). The other is made up of stability muscles (called multifidus) which help adjust one vertebrae on the other as you move. One is strong ligaments that limit motion in certain areas, sort of like flexible duct tape between the blocks. To keep the spine from collapsing, you have two main systems. When was the last time you stacked more than 20 blocks on top of each other without the whole rickety tower collapsing? Think of it this way–your spine is made up of 24 vertebrae that are stacked like kid’s blocks. One of the biggest challenges of walking upright on two legs, rather than on four, is keeping the spine stable. Your spine is made up of the neck (cervical), upper back (thoracic), and low back (lumbar) areas. Radiological Imaging/Shutterstock What Is Spinal Instability?