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Robotic Spine Universe

Structures · Vertebrae

T4 vertebra

Vertebra 4 of the thoracic (chest) spine. This page uses the vertebral level system; the cord segments that lie opposite it have different names.

Show in the 3D spineSee what it connects to in the body

At a glance

Level system
T4 vertebra (vertebral level)
Cord segments opposite its body
T4 to T5Model mapping (PAM50 cord in this column); varies between people. Frostell et al. 2016; De Leener et al. 2018; Cadotte et al. 2014
Canal, front to back × side to side
15.5 × 19.3 mmMeasured on one model: the Visible Human male, imaged as a supine cadaver. Not a normal range
T3 nerve
The T3 nerve exits between the T3 vertebra and the T4 vertebra, below the T3 vertebra.Betts et al. 2022, §13.4
T4 nerve
The T4 nerve exits between the T4 vertebra and the T5 vertebra, below the T4 vertebra.Betts et al. 2022, §13.4

What the sources say

“Below these are the 12 thoracic vertebrae, designated T1–T12.” Betts et al. 2022, §7.3
“Most thoracic vertebrae have two facets located on the lateral sides of the body, each of which is called a costal facet (costal = “rib”).” Betts et al. 2022, §7.3

Connections to the rest of the body

  • Joints

    Twelve pairs of ribs hinge on the thoracic vertebrae

    Each rib meets the thoracic column behind: its head at the body of the vertebra of the same number (and partly the one above), its tubercle at that vertebra’s transverse process.

    Betts et al. 2022, §7.4 · Show on the body

  • Muscle attachments

    Erector spinae: the main extensor of the back

    Three columns of muscle (iliocostalis, longissimus, spinalis) run up the back on each side and straighten the spine.

    Betts et al. 2022, §11.3 · Show on the body

  • Muscle attachments

    Transversospinales: short muscles from process to process

    Deeper, shorter muscles run from the transverse processes of one vertebra to the spinous processes of vertebrae above, to steady and rotate the column.

    Betts et al. 2022, §11.3 · Show on the body

  • Muscle attachments

    Trapezius hangs the shoulder girdle from the spine

    The trapezius spreads from the skull and the spinous processes down the back to the scapula and clavicle.

    Betts et al. 2022, §11.5 · Show on the body

  • Muscle attachments

    Rhomboids tie the scapula to C7–T5

    Rhomboid minor arises from C7 and T1, rhomboid major from T2 to T5; both pull the medial border of the scapula toward the spine.

    Betts et al. 2022, §11.5 · Show on the body

  • Arterial supply

    Posterior intercostal arteries feed the chest wall and spine

    Paired branches leave the thoracic aorta, run along each rib and supply the chest-wall muscles and the vertebral column.

    Betts et al. 2022, §20.5 · Show on the body

  • Venous drainage

    Azygos and hemiazygos veins drain along the spine

    Veins from the chest wall collect into the azygos vein, which runs up the right side of the vertebral bodies, and the smaller hemiazygos on the left.

    Betts et al. 2022, §20.5 · Show on the body

For learning only. Levels and sizes vary between people; nothing here describes a particular person or gives medical advice. Sources: Betts et al. 2022, §7.3; Frostell et al. 2016; De Leener et al. 2018; Cadotte et al. 2014; Betts et al. 2022, §13.4; Betts et al. 2022, §7.4; Betts et al. 2022, §11.3; Betts et al. 2022, §11.5; Betts et al. 2022, §20.5.