Trauma, pinched nerve in the back, muscle strain, or a herniated intervertebral disc in the middle back could be the contributing factors for middle back pain. This Buzzle write-up provides information on the causes of middle back pain on the left side.

The human spine, which is also referred to as the vertebral column, comprises 33 vertebrae that are stacked one on top of the other. It performs the vital function of protecting the spinal cord, which in turn connects the body to the brain. Many nerves of the peripheral nervous system branch out from the spinal cord to various parts of the body. The S-shaped spine is divided into the cervical (neck) spine, thoracic (thorax or chest) spine, and the lumbar (lower back) spine. The vertebrae are connected to each other through ligaments, tendons, and muscles. Between the vertebrae lie intervertebral discs that act as cushions or shock absorbers. The thoracic spine is the middle segment of the vertebral column that lies between the cervical and the lumbar vertebrae. Middle back pain occurs in the event of injury to muscles, bones, tendons, ligaments, or nerves. Inflammation or damage to these structures could occur due to certain medical conditions.

Contributing Factors
Middle back pain could occur due to a wide range of reasons. The pain might radiate to the left side, if the affected structure is located towards the left side.

Muscle Strain
The muscles of the back could get strained due to repeated bending or twisting motions. At times, the muscles could get strained due to lifting heavy objects. Lifting an object in a wrong way could also be a contributing factor. Weightlifters are at a risk of developing strains, as the muscles of the back could get stretched beyond the normal limits. At times, the muscles might develop a tear. The risk of injury is also high when one has to lift heavy objects overhead. Even a blow to the back could cause damage to the muscles. Back pain could also be attributed to a poor posture.

Ligament Sprain
Ligaments are strong bands of fibrous tissue that connect the bones with one another. Their main function is to hold the structures together, thereby providing stability. Ligaments could get strained due to overuse injuries. Blow to the back, twisting motions, lifting heavy objects in an incorrect manner, etc., are some of the causes of a ligament sprain. The severity of pain would depend on the grade of sprain. If the ligament has just been stretched beyond the normal limits, the recovery would be faster. The recovery period would be longer in the event of partial or complete rupturing of the ligament.

Herniated Disc
Intervertebral discs are fibrocartilaginous discs located between the vertebrae. These act as shock absorbers for the vertebrae. Each disc has a hard exterior called annulus fibrosus, and a soft interior called nucleus pulposus. One is diagnosed with a herniated disc, when the hard exterior cracks, causing the soft, jelly-like material to flow out. The jelly-like material can exert pressure on the nerves that are present in the adjoining region. If a nerve gets compressed due to the slipped disc, it could give rise to pain.

Other Causes
Middle back pain could also be experienced by individuals affected by degenerative diseases. Degeneration of vertebrae due to osteoporosis or excessive use of cortisone injections can make the bones susceptible to fractures even with slightest amount of stress on the spine. If the vertebrae located in the middle back region get damaged, it could cause pain in this region. Pain could also be caused due to inflammatory joint conditions such as arthritis or rheumatoid arthritis. Sometimes, people affected by gastroenteritis or stomach flu complain of pain in the middle back.

Treatment
Taking rest is an important part of the treatment. The affected individual should refrain from performing any physical activity that can lead to a muscle strain. Resting the back will allow the affected muscle or ligaments to heal. Application of a heating pad will also provide relief from pain. To reduce inflammation, anti-inflammatory medicines and muscle relaxants are usually prescribed. Doctors usually recommend physical therapy for strengthening the muscles and ligaments. It is only in some rare cases, where the spine has been badly damaged due to an injury or a degenerative disease, that a surgery is recommended.

Upper or middle back pain could be caused due to sitting for long hours in a wrong posture. Thus, improve the posture, and ensure that your back is supported. Also, refrain from lifting very heavy objects, and if you do, make sure that you are lifting them properly. If the back pain persists, consult your healthcare provider for proper diagnosis and treatment.

Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.