Intercostal neuralgia is essentially caused by inherent reasons, or pathological changes in the thoracic vertebrae, ribs, and pleura, leading to an inflammatory symptom involving the intercostal nerves. Therefore, the primary symptom of intercostal neuralgia is pain, but this pain has certain characteristics. First, the pain commonly occurs in the left second rib and the right second, third, and fourth ribs. Second, the range of the pain is usually semicircular; it does not extend beyond the anterior midline at the front or the posterior midline at the back, forming a semicircular pain along the ribs. Third, there are often fixed tender points, which sometimes are located in the costal cartilage or corresponding thoracic vertebrae and paraspinal area; these points, when pressed or tapped, can cause radiating pain. Fourth, many times the examination results are negative, so intercostal neuralgia tends to be a condition where the symptoms are severe, but physical examination often yields very few positive signs.