The site of the left ribs can be generally categorized into two divisions in diagnostic abdominal zoning, the four-quarter and nine-quarter methods. In the nine-partition method, the site of the left rib cage is defined as the left quaternary rib cage, and the organs covered by the left quaternary rib cage are mainly the spleen, stomach, pancreas, as well as the transverse colon, left transverse colon, left transverse colon, splenic flexure of the colon, descending colon, and a part of the mesentery. If there is pain in this area, X-rays, CT, ultrasound, and other ancillary tests are needed to confirm whether there is a substantial organ lesion. Therefore, if the left side of the ribcage is uncomfortable, the first thing to consider is a lesion of one of the organs or structures mentioned above.