Thoracic Vertebrae (T1 - T12)

1. Overview

The thoracic vertebrae (T1–T12) are twelve vertebrae located in the middle segment of the vertebral column. They form the backbone of the thoracic region and are uniquely structured to articulate with the ribs. The thoracic spine provides structural support, protects the spinal cord, and plays a central role in the movement and stability of the trunk.

2. Location

The thoracic vertebrae are positioned between the cervical and lumbar vertebrae:

• Superiorly: Articulate with the last cervical vertebra (C7).

• Inferiorly: Articulate with the first lumbar vertebra (L1).

• Laterally: Articulate with the twelve pairs of ribs, forming the posterior part of the thoracic cage.

They extend from the base of the neck (T1) to just above the abdomen (T12).

3. Structure

Each thoracic vertebra has unique structural features that distinguish it from cervical and lumbar vertebrae:

• Vertebral body: Heart-shaped and larger than cervical vertebrae, increasing in size from T1 to T12.

• Vertebral foramen: Circular and smaller than in the cervical region.

• Spinous process: Long, slender, and angled downward (especially in the mid-thoracic region).

• Transverse processes: Project laterally and contain costal facets for rib articulation (except T11 and T12).

• Superior and inferior articular processes: Oriented in the coronal plane, allowing rotation but limiting flexion and extension.

• Costal facets: Small depressions on the vertebral body and transverse processes for articulating with ribs.

4. Function

The thoracic vertebrae contribute to essential spinal and thoracic functions:

• Protect the spinal cord: Form the vertebral canal through which the spinal cord passes.

• Support the thoracic cage: Anchor the ribs and maintain the shape of the rib cage.

• Enable trunk rotation: The coronal orientation of the facet joints allows rotational movement of the spine.

• Load distribution: Transmit axial loads from the upper body to the lower spine.

5. Physiological role(s)

In addition to structural roles, thoracic vertebrae participate in physiological functions:

• Breathing mechanics: Serve as the posterior attachment for ribs, assisting in respiratory movements.

• Muscle attachment: Provide sites for numerous muscles involved in posture, respiration, and trunk movement.

• Neural communication: Spinal nerves exiting the thoracic vertebrae innervate the thoracic wall, abdominal wall, and part of the upper limb.

6. Clinical Significance

The thoracic vertebrae are associated with various medical conditions:

• Compression fractures:

  • Common in osteoporosis, especially in postmenopausal women and the elderly; lead to kyphotic deformity and pain.

• Scoliosis:

  • Lateral curvature of the spine often involves the thoracic vertebrae, affecting posture and lung function.

• Kyphosis:

  • Excessive forward curvature of the thoracic spine, may be congenital, postural, or due to vertebral compression.

• Herniated thoracic discs:

  • Less common than in cervical/lumbar regions but can compress the spinal cord, leading to myelopathy or radiculopathy.

• Traumatic injury:

  • High-energy trauma (e.g., motor vehicle accidents) can lead to fracture-dislocations requiring surgical stabilization.

• Spinal metastases:

  • Thoracic vertebrae are common sites for metastatic cancer spread (e.g., breast, prostate, lung), potentially compressing the spinal cord.