Thoracic Joint and Bone
There are twelve thoracic vertebrae and they are intermediate in size between the cervical and lumbar vertebrae; they increase in size going towards the lumbar vertebrae. They are distinguished by the presence of facets on the sides of the bodies for articulation with the heads of the ribs, as well as facets on the transverse processes of all, except the eleventh and twelfth, for articulation with the tubercles of the ribs. By convention, the human thoracic vertebrae are numbered T1–T12, with the first one (T1) located closest to the skull and the others going down the spine toward the lumbar region.
Thoracic Joint and Bone
The thoracic vertebrae are a group of twelve small bonesthat form the vertebral spine in the upper trunk. Thoracic vertebrae are unique among the bones of the spine in that they are the only vertebrae that support ribs and have overlapping spinous processes.
The cartilaginous joints in your thoracic cage allow you to breathe. The 1st ribs don’t move at all, but the act of breathing requires the other ribs to move up and down a bit, so the joints formed between the rest of the ribs and thoracic vertebrae allow for some movement.
The joints of the thoracic spine can be divided into two groups – those that are present throughout the vertebral column, and those unique to the thoracic spine.
Present throughout Vertebral Column
There are two types of joints present throughout the vertebral column:
- Between vertebral bodies – adjacent vertebral bodies are joined by intervertebral discs, made of fibrocartilage. This is a type of cartilaginous joint, known as a symphysis.
- Between vertebral arches – formed by the articulation of superior and inferior articular processes from adjacent vertebrae. It is a synovial type joint.
Unique to Thoracic Spine
The articulations between the vertebrae and the ribs are unique to the thoracic spine. For each rib, there are two separate articulations – costovertebral and costotransverse.
Each costovertebral joint consists of the head of the rib articulating with:
- Superior costal facet of the corresponding vertebra
- Inferior costal facet of the superior vertebra
- Intervertebral disc separating the two vertebrae
Within this joint, the intra-articular ligament of head of rib attaches the rib head to the intervertebral disc. Only slight gliding movements can occur at these joints, due to the close articulation of their components.
The costotransverse joints are formed by the articulation of transverse processes of a thoracic vertebra and the tubercle of the adjacent rib. They are present in all vertebrae except T11 and T12.
Common conditions of thoracic bones and joints include:
- Thoracic Osteoarthritis
- Thoracic Fracture
- Facet Joint Disorders