Acute Back Sprain Anatomy
To better understand acute back strain or sprain, it helps to understand the anatomy of the back and spine.
The back includes the spine and the structures that surround the spine. The spine is an upright row of stacked bones, called the vertebral column. Individual bones of the spine are called vertebrae. The vertebral column starts under the skull and continues to the buttocks.
Bones of the spine:
The front of each vertebra is a round, solid cylinder of bone. Between each pair of vertebrae, a disk attaches to the bottom of the vertebra above it, and to the top of the vertebrae below it. The discs act as rubber cushions between the vertebrae. In addition, strong ligaments and muscles hold the vertebral column together. These structures support, surround, and protect the spinal cord.
Anatomy of the vertebrae, disks and muscles:
The back of each vertebra is an open ring of bone. Because the vertebrae are stacked on top of one another, the open rings form a tube that surrounds the spinal cord. The spinal cord is a thick bundle of nerves that starts at the bottom of the brain and continues down the spine. The spinal cord carries messages between the body and the brain. Nerves branch off of the spinal cord between each of vertebrae.
Anatomy of the disks, nerves, and spinal cord:
- Papadopoulos EC, Khan SN. Piriformis syndrome and low back pain: a new classification and review of the literature. Orthop Clin North Am. 2004 Jan;35(1):65-71. 
- Rugulies R, Krause N. Job strain, iso-strain, and the incidence of low back and neck injuries. A 7.5-year prospective study of San Francisco transit operators. Soc Sci Med. 2005 Jul;61(1):27-39. 
- Tveito TH, Hysing M, Eriksen HR. Low back pain interventions at the workplace: a systematic literature review. Occup Med (Lond). 2004 Jan;54(1):3-13. 
- van der Roer N, Goossens ME, Evers SM, van Tulder MW. What is the most cost-effective treatment for patients with low back pain? A systematic review. Best Pract Res Clin Rheumatol. 2005 Aug;19(4):671-84.