According to Mayfield Clinic, a magnetic resonance imaging, or MRI, scan can reveal the presence of a pinched nerve. An MRI uses magnetic imaging to show the body's soft tissues, including nerve and brain tissue.
During the MRI test, the patient lies on a bed that slides into the tube-shaped MRI machine, states Mayfield Clinic. The examination generally lasts between 20 and 50 minutes.
According to Mayo Clinic, doctors suspect a pinched nerve if the patient experiences numbness, tingling, sharp pain or muscle weakness. A pinched nerve occurs when pressure from bones, tendons, cartilage or muscles places pressure on the nerve, preventing it from functioning properly.