The human spinal column consists of 33 stacked bones, or vertebrae, which provide flexible support and protection for the spinal cord. These vertebrae are organized into four main regions: cervical (neck), thoracic (upper and mid-back), lumbar (lower back), and the fused sacral and coccygeal sections. The thoracic spine comprises 12 vertebrae (T1 through T12), forming the longest section of the column. T11 is the eleventh vertebra in this segment, positioned near the bottom, where the spine transitions toward the lower back.
Identifying the Thoracic Spine and T11
T11 is located at the lower end of the thoracic region, directly above the T12 vertebra. This placement puts it at the thoracolumbar junction, where the rigid thoracic spine meets the more flexible lumbar spine. Its position can generally be palpated in the mid-to-lower back.
T11 articulates solely with the 11th pair of ribs, which are considered “floating ribs” because they do not connect to the sternum. The body of the T11 vertebra is more robust and larger than those higher in the thoracic spine, reflecting its increasing role in supporting body weight. The spinous process—the bony projection extending backward—is shorter and more horizontal compared to the long, downward-pointing processes found in the middle thoracic region.
Structural Function of T11
The function of the T11 vertebra is to provide stability, bear the weight of the upper torso, and protect the spinal cord within the vertebral canal. Its location at the thoracolumbar junction means it serves as a transitional vertebra, possessing anatomical features of both the thoracic and lumbar segments.
The orientation of the facet joints, which guide movement, begins to change at this level. The superior facets still face thoracically, but the inferior facets adopt the more sagittal (front-to-back) orientation characteristic of the lumbar spine. This transition allows for slightly more movement than the rest of the upper back, which is restricted by the rib cage. This increase in mobility, combined with the structural change, makes the T11 segment susceptible to higher mechanical stresses during twisting and bending.
Nerves Connecting to T11
The T11 spinal nerve exits the spinal canal through the intervertebral foramen, located between the T11 and T12 vertebrae. This mixed nerve contains both motor and sensory fibers. Upon exiting, the nerve splits into branches that travel backward to the deep muscles and skin of the back and forward toward the torso.
The anterior branch continues along the abdominal wall as the eleventh intercostal nerve, providing sensory innervation to the skin and motor control to the muscles of the upper abdomen. The area of skin supplied by the T11 spinal nerve is its dermatome, covering a band around the flank and upper abdominal region. Damage or compression of the T11 nerve can result in radiculopathy, where pain, numbness, or tingling radiates from the back and wraps around the body along the nerve’s path.
Injuries and Pain Related to T11
Due to its position at the biomechanically active thoracolumbar junction, T11 is vulnerable to injury. This transitional zone absorbs significant forces during activities involving combined flexion and rotation, making it a common site for trauma. Compression fractures are frequently observed at the T11 level, especially in individuals with weakened bone density from conditions like osteoporosis or following high-impact accidents.
The relatively narrow vertebral canal in the thoracic region means that a herniated disc at T11-T12 can place pressure on the spinal cord or the exiting nerve roots. Pain resulting from pathology at this level often includes referred pain that mimics other conditions. Nerve irritation from T11 can cause pain felt in the abdomen or referred downward toward the groin, potentially leading to misdiagnosis if the spinal origin is not considered.