What tests can diagnose left arm pain?

　　Under normal circumstances, left arm pain can be diagnosed through examinations such as X-ray, computed tomography (CT), magnetic resonance imaging (MRI), electromyography (EMG), and arthrography. The specific details are as follows:

　　1. X-ray examination: X-ray imaging can clearly display the shape, structure, and density of the arm bones, helping to detect bone lesions such as fractures, dislocations, bone spurs, osteoporosis, and bone tumors. For arm pain following trauma, X-rays can determine whether a fracture is present. In elderly patients with arm pain, X-rays can assess for osteoporosis and related compression fractures.

　　2. CT scan: CT imaging provides clearer and more precise visualization of bone structures compared to X-rays, allowing better observation of subtle bone abnormalities, such as the extent of bone tumors or detailed fracture patterns. It can also be used to examine calcifications or foreign bodies within the arm's soft tissues, playing an important role in determining the underlying cause.

　　3. Magnetic Resonance Imaging (MRI): MRI is highly effective in visualizing the soft tissues of the arm, including muscles, tendons, ligaments, and nerves. It is valuable for diagnosing soft tissue conditions such as muscle strains, tendonitis, ligament injuries, and nerve compressions. For conditions like rotator cuff injuries or carpal tunnel syndrome, MRI can clearly show the location and severity of the lesion.

　　4. Electromyography (EMG): EMG is primarily used to evaluate the functional status of nerves and muscles. By measuring the electrical activity of muscles at rest and during contraction, it can help determine whether there is nerve damage or muscle disease. For example, in cases of arm pain caused by cervical spondylosis with nerve root compression, EMG can detect abnormal nerve conduction velocities and other changes, aiding in accurate diagnosis.

　　5. Arthrography: Arthrography is commonly used for diagnosing joint disorders, such as those affecting the shoulder or wrist joints. After contrast medium is injected into the joint cavity, imaging techniques such as X-ray or CT can clearly visualize structures like articular cartilage, menisci, synovium, and ligaments, helping to identify minor injuries and pathological changes within the joint, such as meniscal tears or synovial disease.

　　Prior to conducting these examinations, doctors will perform a thorough medical history review and physical examination to narrow down the potential causes and select the most appropriate diagnostic tests accordingly. Therefore, if you experience symptoms such as left arm pain, it is important to seek medical attention promptly and follow the doctor's recommendations for examination and treatment.