"Back" redirects here. For other uses, please see Back (disambiguation).
The human back is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck and the shoulders. It is the surface opposite to the chest, its height being defined by the vertebral column (commonly referred to as the spine or backbone) and its breadth being supported by the ribcage and shoulders. The spinal canal runs through the spine and provides nerves to the rest of the body.

Anatomy of the back
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.

Skeletal structure of the back
The spine is bordered by several groups of muscles, including the intertransversarii muscle which facilitate movement between the individual vertabrae, and the multifidus spinae, which facilitate the movement of the spine as a whole.
Other muscles in the back are associated with the movement of the neck and shoulders. The trapezius muscle, which is named from its trapezium-like shape, runs between the neck, the anterior chain, the two shoulders, and the thoracic vertebra, T12. The large latissimus dorsi make a triangle from the shoulder to the hip. The significant mass of muscles in the back can be developed through back exercises.

Muscles of the back
The intricate anatomy of the back is designed to both provide support for the head and trunk of the body, strength in the trunk of the body, as well as a great deal of flexibility and movement. The upper back has the most structural support, with the ribs attached firmly to each level of the thoracic spine and very limited movement. The lower back allows for flexibility and movement in all directions.

Function of the back

Main article: Back pain Back pain
The lungs are within the ribcage, and extend to the back of the ribcage, making it possible for them to be listened into through the back. The kidneys are situated beneath the muscles in the area below the end of the ribcage, loosely connected to the peritoneum. A strike to the lower back can damage the kidneys of the person being hit.