Thoracic vertebrae

At a glance

English

Thoracic vertebrae

Latin (TA2)

Vertebrae thoracicae

System

Bone

Region

Back

In order

From the vertebra t1 to the vertebra t12

About the thoracic vertebrae

The thoracic vertebrae are the twelve vertebrae of the upper and middle back, T1 to T12, lying between the neck and the lower back. Their defining job is to carry the ribs, so each one bears facets for rib heads on the sides of its body, and most also carry a facet on each transverse process for the tubercle of a rib. Together with the ribs and sternum they form the bony cage of the chest.

A typical thoracic vertebra has a heart-shaped body, a small round canal and a long spine that slopes steeply downward, overlapping the one below. In the middle of the series a rib head sits across two vertebrae, so each body carries a half facet above and a half facet below, one for each of two ribs. The articular facets face mostly backward and forward, which allows rotation but limits bending forward and back. The spinal nerve of each number leaves the canal just below its vertebra.

The series changes from top to bottom. T1 still looks partly cervical and carries a whole facet for the first rib. From T2 to T8 the pattern of paired half facets holds. Lower down, T9 to T12 move towards the lumbar form: the rib facets become single and creep onto the pedicles, the transverse processes lose their rib facets, the bodies grow larger and the spines shorter and more horizontal. T12 has lumbar-style lower facets and acts as the hinge between the stiff thoracic spine and the mobile lumbar spine.

Several of these bones serve as landmarks for structures in front of them. The sternal angle lies level with the T4 to T5 region, where the trachea also divides into the two main bronchi, and the junction of the sternum and xiphoid process lies near T8 to T9.