The left calf is thicker than the right calf, commonly due to the following reasons: First, the patient is left limb dominant, so usually mainly use the left lower limb and left upper limb to generate force, the left calf is fully used, causing local thickening, and muscle strength is also significantly enhanced compared to the opposite side. Second, diseases such as lumbar disc herniation or trauma to the lower limbs can cause secondary atrophy of the right calf muscle, which is related to continuous nerve compression and disuse atrophy of the limb muscles. Patients will show atrophy and thinning of the right calf, with a significant decrease in muscle strength and intensity, and the right calf can be judged to be thinner compared to the left calf according to different causes.