Degenerative disc disease occurs when there is damage to the cartilaginous discs that serve as shock absorbers between the spinal vertebrae. As the discs degenerate, the spaces between spinal bones become thinner and the vertebrae can erode. The body attempts to repair the bones by increasing growth in the damaged area, and bone spurs can result. When bone spurs compress nerves, an individual can experience pain, muscle weakness and organ dysfunction. Tests can help confirm whether such symptoms are the result of disc degeneration or other factors.
Physical Examination
A physician who suspects degenerative disc disease may conduct a number of tests during a physical examination that will help her determine whether her diagnosis is correct, according to the University of Maryland Medical Center. The physician will check the mobility of the spine to see whether there is any loss of range of motion, or instability that may be in keeping with disc disease.
Degenerative disc disease can affect the motor nerves, which supply the muscles, and the physician may test for weakness by checking the patient's ability to lift their arms or legs against resistance. Sensory indicators such as pain, numbness or paresthesia, commonly referred to as a "pins and needles" feeling, can also indicate nerve damage. The physician may evaluate the patient's ability to detect sensations over specific areas supplied by the spinal nerves, known as dermatomes.
Reflexes are an indicator of the nervous system's ability to respond to sensory stimuli with a muscle reaction. Tests of the reflexes in the knee or ankle can contribute useful information to the physician who suspects degenerative disc disease.
X-rays
X-rays are useful in revealing problems with the bones of the spinal column. If degenerative disc disease has resulted in the formation of osteophytes, or bone spurs, x-rays can supply information as to the precise location and degree of any bone overgrowths that may be causing nerve impingement. The University of Maryland Medical Center notes that x-rays do not depict soft tissues, such as nerves and muscles.
Magnetic Resonance Imaging
Magnetic resonance imaging, or MRI, cannot, by itself, confirm degenerative disc disease, but it can reveal damage to discs, according to Cedars-Sinai Medical Center. MRI uses magnetic and radio waves to create a computer-generated image of the spine. MRI images can show soft tissues such as nerves and ligaments, as well as reveal disc herniation, or obstructions to the channels that conduct nerves from the spinal cord to the peripheral nervous system.
