The thoracic spine (T1 to T12) forms the middle section of the back. This region is inherently stable compared to the neck and lower spine because each vertebra connects to a pair of ribs, forming the protective rib cage. Due to its limited range of motion, pain is less common here than in the lower back. When thoracic back pain occurs, the causes are varied, ranging from minor muscle issues to more serious, non-spinal underlying health problems.
Muscular and Soft Tissue Sources
The most frequent source of discomfort in the middle back involves the muscles, tendons, and ligaments that support the spinal column. Overuse, such as from repetitive movements in sports or improper lifting mechanics, can lead to micro-tears and inflammation in the musculature. This results in localized tightness or a dull, persistent ache.
Chronic poor posture, particularly the rounded-shoulder position known as thoracic kyphosis or slouching, is a leading contributor to these soft tissue problems. This prolonged, forward-flexed position places excessive, sustained strain on the posterior muscles and ligaments that must work constantly to pull the spine upright. Ligament sprains can also occur from sudden, forceful movements that exceed the tissue’s capacity.
Structural and Degenerative Spinal Conditions
Pain can originate from chronic wear-and-tear within the bony structures and joints of the thoracic spine. The small joints connecting the vertebrae, called facet joints, can develop Osteoarthritis where the protective cartilage wears down. This degeneration causes localized pain and stiffness that often worsens with twisting or backward extension of the trunk.
Degenerative Disc Disease, while less common in the rigid thoracic region, involves the breakdown of the intervertebral discs. As the disc height decreases, it can place more stress on the surrounding joints and nerves, sometimes leading to the formation of bone spurs, which further limit mobility and cause pain. Spinal deformities also contribute to chronic pain by altering the body’s natural alignment. Conditions like scoliosis (sideways curvature) or excessive kyphosis (forward rounding) place uneven mechanical strain on the vertebrae and supporting ligaments.
Traumatic Injuries
Acute, high-impact events represent a distinct category of thoracic back pain causes. Trauma, such as that sustained in a car accident, a hard fall, or a sports impact, can generate forces that exceed the strength of the spinal components. The most concerning traumatic injury is a vertebral compression fracture, which occurs when a vertebral body collapses.
These fractures are particularly common in the lower thoracic spine (T11 and T12) and may occur even with minor force in individuals with osteoporosis, a condition characterized by low bone mineral density. Compression fractures cause sudden, severe pain that often increases when standing or walking and may be accompanied by a noticeable loss of height or change in posture.
Referred Pain and Internal Causes
Thoracic back pain can also be a manifestation of referred pain, which is discomfort perceived in the back but originating from an organ in the chest or abdomen. This occurs because the internal organs and the skin/muscles of the back share common nerve pathways that connect to the spinal cord.
Serious internal conditions often present as thoracic pain:
- Vascular conditions, such as aortic dissection, cause sudden, severe, sharp pain in the chest or upper back, often described as “tearing.”
- Gastrointestinal problems frequently refer pain to the mid-back, including peptic ulcers (interscapular discomfort) and pancreatitis (severe, boring pain that worsens when lying flat).
- Gallbladder disease can cause pain between the shoulder blades or beneath the right shoulder blade.
- Renal issues, such as kidney stones or infection, cause pain in the flank area just below the ribs, often accompanied by urinary symptoms or fever.
- Spinal infections, like osteomyelitis, cause deep, persistent back pain that does not improve with rest.
- Shingles (herpes zoster) causes severe, burning pain in a band-like pattern around one side of the torso before the characteristic rash appears.
The presence of unexplained back pain that is constant, severe, or accompanied by systemic symptoms requires prompt medical evaluation to rule out these serious internal causes.