The left upper abdomen rib cage has been shaking may be intercostal muscle spasm, calcium deficiency and other related, may also be caused by plant nerve dysfunction. 1. Intercostal muscle spasm: generally because of prolonged fatigue, strenuous exercise, intercostal nerve stimulation, prolonged sedentary posture related, can do more hot compresses and massage treatment. 2. Calcium deficiency: there are symptoms of cramps in general the possibility of calcium deficiency, you can generally take oral calcium gluconate oral solution for treatment, more sunshine in the daily. You can go to the hospital to do a trace element test to see if other aspects of the lack of. 3. Phytoneurological disorders: prolonged late night, mental stress, psychological pressure may cause phytoneurological disorders, there will be the left epigastrium near the ribs is always trembling. If the epigastric rib muscles have been shaking, you need to see a doctor as soon as possible to receive treatment, so as not to delay the condition.