5.1 General Information

• T1–T12 are defined as the thoracic vertebrae ( Table 5.1 ):

• Kyphotic curvature: 20–40 degrees:

  • Apex of kyphosis at T7–T8:

    • Pathologic kyphosis can have an apex at any level.

• Articulate with their corresponding ribs at facet joints, limited range of motion:

  • Flexion–extension minimal at T1–T2; maximum T12–L1.

  • Axial rotation minimal at thoracolumbar junction; maximum at T12.

• Wedge shaped with anterior height shorter than posterior height.

• Width of vertebral canal is smallest in the thoracic vertebrae.

5.2 Bony Anatomy

(Fig. 5.1)

• Vertebral body:

  • Anterior border of intervertebral foramen.

  • Forms articulation with ribs:

    • Each rib articulates with two vertebral bodies:

      • Inferior costal demifacet of superior vertebral body and superior costal facet of inferior vertebral body.

  • Superior costal demifacet:

    • Superoposterior edge of vertebral body.

    • Articulates with corresponding rib of same number.

    • Exceptions:

      • Superior costal facet of T1 is not a demifacet:

        • First rib only articulates with T1.

      • T10 has one pair of complete costal facets located between the vertebral body and pedicle.

      • T11 and T12 have one pair of complete costal facets located on the pedicles.

  • Inferior costal demifacet:

    • Inferoposterior edge of vertebral body.

    • Articulates with head of rib below.

• Pedicle:

  • Height of pedicle is double that of the width.

  • Inferior notch is superior border of intervertebral foramen.

  • Superior notch is inferior border of intervertebral foramen.

  • Pedicle diameter is maximal at T1 and minimal at T6:

    • Diameter gradually increases again from T6.

• Superior articular process:

  • Faces posterolaterally.

  • Articulates with inferior articular process of adjacent superior vertebrae.

• Inferior articular process:

  • Faces anteromedially.

  • Articulates with superior articular process of adjacent inferior vertebrae.

• Lamina.

• Posterior border of vertebral foramen.

• Transverse process:

  • Forms the costotransverse joint.

  • T1–T10 have a costal facet on transverse process that articulates with tubercle of rib.

• Spinous process:

  • Long, points downward.

  • Becomes level with body of vertebrae below.

5.3 Ligamentous Anatomy

• Radiate ligament of head of rib:

  • Attaches head of rib to bodies and disk.

  • Reinforces costovertebral joint anteriorly.

• Costotransverse ligament:

  • Attaches neck of rib to transverse process.

• Superior costotransverse ligament:

  • Attaches rib to transverse process of superior vertebrae.

• Intratransverse ligament:

  • Fibrous cords that join adjacent thoracic vertebrae and blend with adjacent back muscles.

• Lateral costotransverse ligament:

  • Attaches transverse process to tubercle of rib.