Dos

The human back, also called the dorsum (: dorsa), is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck. It is the surface of the body opposite from the chest and the abdomen. The vertebral column runs the length of the back and creates a central area of recession. The breadth of the back is created by the shoulders at the top and the pelvis at the bottom. Back pain is a common medical condition, generally benign in origin. The central feature of the human back is the vertebral column, specifically the length from the top of the thoracic vertebrae to the bottom of the lumbar vertebrae, which houses the spinal cord in its spinal canal, and which generally has some curvature that gives shape to the back. The ribcage extends from the spine at the top of the back (with the top of the ribcage corresponding to the T1 vertebra), more than halfway down the length of the back, leaving an area with less protection between the bottom of the ribcage and the hips. The width of the back at the top is defined by the scapula, the broad, flat bones of the shoulders. Gray204.png|View of the bones of the thorax and shoulders from behind. Back Muscles.jpg|Posterior view of muscles connecting the upper extremity to the vertebral column.A TrapeziusB Teres MajorC Teres MinorD Latissimus DorsiE Levator ScapulaeF Rhomboid Major Gray798-back crop.png|Distribution of [[cutaneous nerve]]s, dorsal aspect. Dorsal and lateral cutaneous branches labeled at center right. The muscles of the back can be divided into three distinct groups; a superficial group, an intermediate group and a deep group. The superficial group, also known as the appendicular group, is primarily associated with movement of the appendicular skeleton. It is composed of trapezius, latissimus dorsi, rhomboid major, rhomboid minor and levator scapulae. It is innervated by anterior rami of spinal nerves, reflecting its embryological origin outside the back.