Crouching Tiger, Hidden Dragon refers to latissimus dorsi. Located under the skin of the back and posterolateral chest, latissimus dorsi is the largest latissimus dorsi muscle in the whole body. It is a right triangle, and the upper part of the inside is covered by trapezius muscle. The aponeurosis originates from the spinous process of the lower six thoracic vertebrae, all spinous processes of the lumbar vertebrae and the posterior lip of the external iliac crest 1/3.

There are about 639 human muscles. It consists of about 6 billion muscle fibers, the longest is 60 cm, the shortest is only about 1 mm, the big muscle weighs about two kilograms, and the small muscle weighs only a few grams. The average person's muscles account for about 35% to 45% of the body weight.