Thoracic cage

The skeleton or cage that joins the thoracic vertebrae and the sternum is called the thoracic skeleton. It looks barrel shaped. It consists of 12 thoracic vertebrae, 12 pairs of vertebrae and a sternum.
1. Rib: The narrow, long, compressed and curved bone in the thoracic skeleton is called rib. Their number is 24. Each Parshuka consists of three parts. Neck, tubercle and body. Parshukas can be divided into two categories. Namely – real Rib and fake Rib.
(i) Real or True Rib: Those Ribs which have one end attached to the thoracic vertebrae and the other end to the sternum are called original Rib. The first 7 pairs of Ribs are the original Parshukas Rib.
(ii) False Rib: Rib which has one end attached to the thoracic vertebra, but the other end is not attached to the sternum is called a false Rib. 8th-12th pair of parshukas Ribs are duplicate Ribs. Among them, the 8th, 9th and 10th vertebrae join together to form the costal arch. The ends of the 11th and 12th vertebrae are free or floating. These are called floating vertebrae. Between every two vertebrae are external and internal intercostal muscles. The space between the costal cartilages is called the intercostal space.
2. Sternum: The compressed bone located in the center of the chest is called the sternum. Its length is 15-17 cm. It is a complex bone. It consists of a jugular notch, a clavicle and 7 pairs of parsicular grooves. It consists of three parts. namely manubrium, body and xiphoid process.

Neural arch

The ring or ring-like part formed from the surface of the vertebrae is called arch. The parts of the arch are:
(i) Pedicle: Thick, short and hard bone formed from the back of vertebra is called pedicle.
(ii) Transverse process: Both the extensions arising from the junction of pedicle and lamina are called transverse processes.
(iii) Lamina : The lamina is a flat, flat and plate-like bone lying between the transverse process and the spinous process.
(iv) Articular process or Zygapophysis: Each vertebra has pre-zygapophysis (superior) anteriorly and post-zygapophysis (inferior) posteriorly. The superior articular process of one vertebra articulates with the inferior articular process of another vertebra.
(v) Spinus process : The amplifier arising from lamina is called spinous process.

Normal Vertebral-Structure

The structural unit of the spine is called a vertebra. There are slight differences in structure as the vertebrae are located in different parts of the spine. A typical vertebra consists of three segments. Centrum, neural arch and neural foramen/canal.
1. Centrum: The main part of the vertebra is the centrum. It is large and oval in shape. It is hard, thick and spongy bone.
2. Neural arch: The ring or ring-like part formed from the surface of the vertebrae is called arch. The parts of the arch are:
(i) Pedicle: Thick, short and hard bone formed from the back of vertebra is called pedicle.
(ii) Transverse process: Both the extensions arising from the junction of pedicle and lamina are called transverse processes.
(iii) Lamina : The lamina is a flat, flat and plate-like bone lying between the transverse process and the spinous process.
(iv) Articular process or Zygapophysis: Each vertebra has pre-zygapophysis (superior) anteriorly and post-zygapophysis (inferior) posteriorly. The superior articular process of one vertebra articulates with the inferior articular process of another vertebra.
(v) Spinus process : The amplifier arising from lamina is called spinous process.
3. Neural foramen/canal
(i) Intervertebral foramen: The hole in the pedicle is called intervertebral foramen. It contains smooth nerves and blood vessels.
(ii) Vertebral foramen: The large opening in each vertebra is called vertebral foramen.
(iii) Vertebral canal: Vertebral foramen of vertebrae join together to form vertebral canal.