The back structure of the human skeleton has the human vertebrae and scapula. 1. The scapula is a triangular flat bone, attached to the posterior outside of the thorax, between the 2nd and 7th ribs, and can be divided into two sides, three edges and three corners. (1) Two sides: the ventral or ribbed side is opposite to the thorax, and the transverse ridge on the dorsal side is called the scapular ridge. (2) Three margins: the upper margin is short and thin, the lateral portion has a scapular notch, and the more lateral portion has a forward finger-like projection called the rostral process. The medial margin is thin and sharp, and is also called the spinal margin because of its proximity to the spine. The lateral margin is hypertrophied adjacent to the axilla and is called the axillary margin. (3) Three corners: the upper corner is where the upper margin meets the spinal margin, flat against the second rib. The lower corner is where the spinal margin meets the axillary margin, flat against the 7th rib or the 7th rib gap, and is the marker for counting ribs. The lateral angle is where the axillary margin meets the superior margin, and is more hypertrophic, with a shallow pear-shaped fossa toward the lateral side, called the glenoid. Among them, the scapular ridge, the acromion, the subscapular angle, the medial border and the rostral eminence can be seen on the surface of the body. 2. In early childhood, the spine is 32 or 33 vertebrae, divided into 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 sacral vertebrae, and 3-4 caudal vertebrae. In adulthood, the 5 sacral vertebrae fuse to form the sacrum, and the 3-4 caudal vertebrae fuse to form the coccyx. The vertebrae consist mainly of short cylindrical vertebrae at the front and plate-like vertebral arches at the back, which serve to support the body and cushion the forces of movement. Men and women have the same bone structure. However, men’s bones are thicker and longer than women’s bones, the bone surface is more uneven and bumpy, and the osteophytes are heavier.