The location of the underwear buckle generally corresponds to the fourth thoracic vertebrae or the fifth thoracic vertebrae, the main causes of pain here are the following aspects: 1, there may be supraspinous ligamentitis or interspinous ligamentitis, supraspinous ligament and interspinous ligament are attached to the thoracic vertebrae on the spinal protuberance and interspinous ligament, inflammation of which may lead to pain in the place of the underwear buckle. 2, there may be thoracic vertebrae small joints disorders because the human body has 12 thoracic vertebrae, the thoracic vertebrae are composed of the upper joints and lower joints to stabilize the thoracic vertebrae. Thoracic spine, thoracic spine is a joint composed of the upper and lower articular synapses each other, so as to maintain the stability of the thoracic spine, the occurrence of joint disorders may lead to pain. 3, it may be the dorsal myofascial inflammation, dorsal myofascial is the part between the skin and muscle, inflammation may lead to the spine of the vertebral bone here is more painful when pressed. The main reason is the above aspects.