The thoracic portion of the spine is the longest part and is made up of twelve vertebrae (T1-T12). They lie between the cervical spine (C1-C7) and the lumbar spine (L1-L5). The thoracic spine protects the very important spinal cord that begins in the brain and runs down to approximately T12. T12 is where the cord turns into what looks like a horse’s tail (the cauda equina). The spinal nerves then travel into the lumbar spine and sacrum (tailbone). It innervates the low back, pelvis, legs, and feet. Nerve roots exit at each vertebral level of the spine innervating the upper (cervical), middle (thoracic), and lower (lumbar) portions of the body.

T1-T12 Nerves

Looking closer at the T1-T12 nerves, T1-T2 nerves innervates motor/muscle and sensory/feeling. It innervates the top of the chest, inner arms, and hands (providing strength to the deep, intrinsic hand muscles). Nerves T3-T5 innervate the chest wall and help control the rib cage, lungs, and diaphragm. The diaphragm is the breathing muscle that separates the chest cavity from the abdominal cavity. The T6-T12 nerves innervate the abdominal and back muscles. They work with the lumbar nerves to help stabilize our core, balance, posture, and the coughing process.

The thoracic spine also supports the rib cage. It protects our lungs, heart, and the great vessels that supply our body with fresh, oxygenated (arterial) blood. It also trades off carbon dioxide (venous blood) for oxygen in the lungs each time we take a breath. All of this happens automatically, thanks to our autonomic nervous system (ANS). ANS composes of sympathetic and parasympathetic nerves of which many sympathetic nerves arise in the thoracic region!

Potential Causes

Unlike the cervical and lumbar portions of the spine, the thoracic spine is much more rigid and stable. It leads to a lower risk of injury. Potential causes of mid-back pain include poor posture; prolonged sitting; or conditions like scoliosis (curvature) or hyper-kyphosis (increased “humping” of the TS); sprain of the ligaments that hold bones firmly together (usually by a sudden, unexpected movement or trauma); bruising, cracking, or fracturing of the ribs or thoracic vertebrae; compression fracturing due to osteoporosis; and overuse injuries from repetitive lifting, bending, and twisting.

Doctors of chiropractic are trained to evaluate and treat patients with MBP utilizing various forms of manual therapies (including spinal manipulation, mobilization, and massage), exercise training, posture retraining, and more.