CT not only examines bones, but also provides a clearer picture than traditional X-ray. CT exams are non-invasive, easy and quick to examine, and can provide cross-sectional images without tissue overlap. To give a common example, a watermelon is a round ball with X-rays, which cannot determine whether the watermelon is ripe or not. Using CT examination is equivalent to cutting the watermelon into several thin slices, and it is possible to clearly see the degree of ripeness and how many seeds are inside the watermelon. Therefore, CT examination can be applied to the skeletal system to detect subtle fractures of the skull, spine, limbs, joints, early bone tumors, femoral head necrosis, etc. CT examination has a certain degree of radiation, and special attention should be paid to pregnant women and those who are in critical condition and have difficulty cooperating with CT examination.