1.Pain The most common symptom of primary osteoporosis is low back pain, which accounts for 70%-80% of the patients with pain. The pain spreads along the spine to both sides, decreases when lying on the back or sitting, increases when posterior extension or prolonged standing or sitting, is light during the day and increases when waking up at night and early in the morning, and increases when bending, muscle movement, coughing and stooling. Bone pain generally occurs when 12% or more of bone mass is lost. In old age osteoporosis, the vertebral trabeculae atrophy, the number decreases, the vertebral body compresses and deforms, the spine flexes forward, the lumbar muscles double contraction in order to correct the forward flexion of the spine, muscle fatigue or even spasm, producing pain. A recent compression fracture of the thoracolumbar spine can also produce acute pain, with strong pressure and percussion pain in the spinal spinous process of the corresponding area, which can generally be gradually reduced after 2-3 weeks, and some patients can present with chronic low back pain. If the corresponding spinal nerve is compressed, radiating pain in the extremities, sensory-motor disorders in both lower extremities, intercostal neuralgia, retrosternal pain similar to angina pectoris, or epigastric pain similar to acute abdomen may occur. If the spinal cord and cauda equina are compressed, the bladder and rectal function will be affected. 2. Shortening of body length and hunchback Most of them appear after the pain. The front part of the vertebrae of the spine is almost mostly composed of cancellous bones, and this part is the pillar of the body with a large weight, especially the 11th and 12th thoracic vertebrae and the 3rd lumbar vertebrae, which have a greater load and are easily compressed and deformed, causing the spine to tilt forward and the back curve to increase, resulting in a hunchback, and as we age, osteoporosis increases and the curvature of the hunchback increases, resulting in a significant weight on the knee joint. Each person has 24 vertebrae, the height of each vertebrae is about 2cm in normal people, when the elderly osteoporosis vertebrae compression, each vertebrae shortened by about 2mm, the average length of the body shortened by 3-6cm. 3, fracture This is the most common and most serious complications of degenerative osteoporosis. 4.Decreased respiratory function: compression fractures of thoracic and lumbar vertebrae, backward curvature of the spine, and thoracic deformity can significantly reduce lung capacity and maximum air exchange, and patients can often experience chest tightness, shortness of breath, and difficulty in breathing.