Tests for Musculoskeletal Disorders

X-rays Plain X-Rays X-rays are high-energy radiation waves that can penetrate most substances (to varying degrees). In very low doses, x-rays are used to produce images that help doctors diagnose disease. In high... read more are typically done first. They are most valuable for detecting abnormalities in bone and are taken to evaluate painful, deformed, or suspected abnormal areas of bone. Often, x-rays can help to diagnose fractures Overview of Fractures A fracture is a crack or break in a bone. Most fractures result from force applied to a bone. Fractures usually result from injuries or overuse. The injured part hurts (especially when it is... read more , tumors Overview of Bone Tumors Bone tumors are growths of abnormal cells in bones. Bone tumors may be cancerous (malignant) or noncancerous (benign). Cancerous tumors may start in the bone (primary cancer) or start in other... read more , injuries, infections Osteomyelitis Osteomyelitis is a bone infection usually caused by bacteria, mycobacteria, or fungi. Bacteria, mycobacteria, or fungi can infect bones by spreading through the bloodstream or, more often, by... read more , and deformities (such as developmental dysplasia of the hip Developmental Dysplasia of the Hip Developmental dysplasia of the hip is a birth defect in which the bones in the hip are incorrectly developed. Birth defects, also called congenital anomalies, are physical abnormalities that... read more ). Also, sometimes x-rays are helpful in showing changes that confirm a person has a certain kind of arthritis (for example, rheumatoid arthritis Diagnosis Rheumatoid arthritis is an inflammatory arthritis in which joints, usually including those of the hands and feet, are inflamed, resulting in swelling, pain, and often destruction of joints.... read more or osteoarthritis Diagnosis Osteoarthritis is a chronic disorder that causes damage to the cartilage and surrounding tissues and is characterized by pain, stiffness, and loss of function. Arthritis due to damage of joint... read more ). X-rays do not show soft tissues such as muscles, bursae, ligaments, tendons, or nerves.

To help determine whether the joint has been damaged by injury, a doctor may use an ordinary (non-stress) x-ray or one taken with the joint under stress caused by certain positions (stress x-ray).

Arthrography is an x-ray procedure in which a radiopaque dye is injected into a joint space to outline the structures, such as ligaments inside the joint. Arthrography can be used to view torn ligaments and fragmented cartilage in the joint. However, magnetic resonance imaging Computed tomography (CT) and magnetic resonance imaging (MRI) A doctor can often diagnose a musculoskeletal disorder based on the history and the results of a physical examination. Laboratory tests, imaging tests, or other diagnostic procedures are sometimes... read more (MRI) is now generally used in preference to arthrography.

Bone scanning (a type of radionuclide scanning Radionuclide Scanning In radionuclide scanning, radionuclides are used to produce images. A radionuclide is a radioactive form of an element, which means it is an unstable atom that becomes more stable by releasing... read more ) is an imaging procedure that is occasionally used to diagnose a fracture, particularly if other tests, such as plain x-rays and computed tomography (CT) or magnetic resonance imaging (MRI), do not reveal the fracture. Bone scanning involves use of a radioactive substance (technetium-99m–labeled pyrophosphate) that is absorbed by any healing bone. The procedure can also be done when a bone infection or a tumor that has spread from a cancer elsewhere in the body is suspected.

Although a bone scan may show a problem in the bone, it may not show whether the problem is a fracture, tumor, or infection. The radioactive substance is given by vein (intravenously) and is detected by a bone-scanning device, which creates an image of the bone that can be viewed on a computer screen.

Computed tomography Computed Tomography (CT) In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually... read more (CT) and magnetic resonance imaging Magnetic Resonance Imaging (MRI) In magnetic resonance imaging (MRI), a strong magnetic field and very high frequency radio waves are used to produce highly detailed images. MRI does not use x-rays and is usually very safe... read more (MRI) give much more detail than conventional x-rays and may be done to determine the extent and exact location of damage. These tests can also be used to detect fractures that are not visible on x-rays.

MRI is especially valuable for imaging muscles, ligaments, and tendons. MRI can be used if the cause of pain is thought to be a severe soft-tissue problem (for example, rupture of a major ligament or tendon or damage to important structures inside the knee joint).

CT is useful if MRI is not recommended or unavailable. CT exposes people to ionizing radiation (see Risks of Radiation in Medical Imaging Risks of Radiation in Medical Imaging Imaging tests that use radiation, usually x-rays, are a valuable tool in diagnosis, but exposure to radiation has some risks (see also Radiation Injury). Different diagnostic tests require different... read more ). CT best images bone. However, MRI is better than CT for imaging some bone abnormalities, such as small fractures of the hip and pelvis. The amount of time a person spends undergoing CT is much less than for MRI. MRI is more expensive than CT and, with the exception of when the open-sided units are used, many people feel claustrophobic inside the MRI unit.

The most accurate way to evaluate bone density, which is necessary when screening for or diagnosing osteopenia or osteoporosis Bone density testing Osteoporosis is a condition in which a decrease in the density of bones weakens the bones, making breaks (fractures) likely. Aging, estrogen deficiency, low vitamin D or calcium intake, and... read more , is with dual-energy x-ray absorptiometry (DXA). DXA is also used to predict a person's risk of fracture and can be useful for monitoring the response to treatment as well. This test is quick and painless and involves very little radiation.

In this test, x-rays are used to examine bone density at the lower spine, hip, wrist, or entire body. Measurements of bone density are very accurate at these sites. When screening people for osteoporosis Bone density testing Osteoporosis is a condition in which a decrease in the density of bones weakens the bones, making breaks (fractures) likely. Aging, estrogen deficiency, low vitamin D or calcium intake, and... read more , doctors prefer taking measurements of the lower spine and hip. To help differentiate osteoporosis (the most common cause of an abnormal DXA scan result) from other bone disorders, doctors may need to consider the person's symptoms, medical conditions, drug use, and certain blood or urine test results as well as the DXA results.

Ultrasonography Ultrasonography Ultrasonography uses high-frequency sound (ultrasound) waves to produce images of internal organs and other tissues. A device called a transducer converts electrical current into sound waves... read more is being used more and more frequently to identify abnormalities and inflammation in and around joints and tears or inflammation of tendons. Ultrasonography is also used as a guide when a needle needs to be put into a joint (for example, to inject drugs or to remove joint fluid). As an alternative to computed tomography Computed Tomography (CT) In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually... read more (CT) and magnetic resonance imaging Magnetic Resonance Imaging (MRI) In magnetic resonance imaging (MRI), a strong magnetic field and very high frequency radio waves are used to produce highly detailed images. MRI does not use x-rays and is usually very safe... read more (MRI), ultrasonography is less expensive and, unlike CT, involves no exposure to radiation.

Arthroscopy is a procedure in which a small (diameter of a pencil) fiberoptic scope is inserted into a joint space, allowing the doctor to look inside the joint and to project the image onto a video monitor. The skin incision is very small. This procedure is done in a hospital or surgical center. The person is given local, spinal, or general anesthesia Anesthesia Surgery is the term traditionally used to describe procedures (called surgical procedures) that involve manually cutting or stitching tissue to treat diseases, injuries, or deformities. However... read more or a combination.

During arthroscopy, doctors can take a piece of tissue (such as joint cartilage or the joint capsule) for analysis (biopsy), and, if necessary, do surgery to correct the condition. Disorders commonly found during arthroscopy include

Such conditions affect people with arthritis or previous joint injuries as well as athletes. Most of these conditions can be repaired or removed during arthroscopy. There is a very small risk of joint infection with this procedure.

Recovery time after arthroscopic surgery is much faster than after traditional surgery. Most people do not need to stay overnight in the hospital.

Joint aspiration is used to diagnose certain joint problems. For example, it is the most direct and accurate way to determine whether joint pain and swelling is caused by an infection or crystal-related arthritis (such as gout Diagnosis Gout is a disorder in which deposits of uric acid crystals accumulate in the joints because of high blood levels of uric acid (hyperuricemia). The accumulations of crystals cause flares (attacks)... read more ).

For this procedure, a doctor first injects an anesthetic to numb the area. Then the doctor inserts a larger needle into the joint space (sometimes guided by ultrasonography), draws out (aspirates) joint fluid (synovial fluid), and examines the fluid under a microscope. A doctor removes as much fluid as possible and notes its color and clarity. Other tests, such as white blood cell count and culture, are done on the fluid.

The doctor can often make a diagnosis after analyzing the fluid. For example, a sample of fluid may contain bacteria, which confirm a diagnosis of infection. Or, it may contain certain crystals. For example, finding uric acid crystals confirms a diagnosis of gout Diagnosis Gout is a disorder in which deposits of uric acid crystals accumulate in the joints because of high blood levels of uric acid (hyperuricemia). The accumulations of crystals cause flares (attacks)... read more , and calcium pyrophosphate dihydrate crystals confirm a diagnosis of calcium pyrophosphate arthritis (pseudogout Calcium Pyrophosphate (CPP) Arthritis Calcium pyrophosphate (CPP) arthritis (previously called pseudogout) is a disorder caused by deposits of calcium pyrophosphate dihydrate crystals in the joint cartilage, leading to intermittent... read more ).

Usually done in the doctor's office or an emergency department, this procedure is typically quick, easy, and relatively painless. The risk of joint infection is minimal.

Nerve conduction studies Nerve conduction studies Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more help determine whether the nerves supplying the muscles are functioning normally. Electromyography Electromyography Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more , usually done at the same time as nerve conduction studies, is a test in which electrical impulses in the muscles are recorded to help determine how well the impulses from the nerves are reaching the connection between nerves and muscles (neuromuscular junction) and, from there, the muscles.

Nerve conduction studies, together with electromyography, help indicate whether there is a problem primarily in the

Nerve conduction studies are particularly useful for the diagnosis of peripheral nerve disorders Overview of the Peripheral Nervous System The peripheral nervous system refers to the parts of the nervous system that are outside the central nervous system, that is, those outside the brain and spinal cord. Thus, the peripheral nervous... read more , such as carpal tunnel syndrome Carpal Tunnel Syndrome Carpal tunnel syndrome is a painful compression (pinching) of the median nerve as it passes through the carpal tunnel in the wrist. The cause of most cases of carpal tunnel syndrome is unknown... read more and ulnar nerve palsy Ulnar nerve palsy Mononeuropathy is damage to a single peripheral nerve. Pressure on a nerve for a long time is the most common cause of mononeuropathy. The affected area may tingle, feel prickly, or be numb... read more .