What are the vertebrae made of?

With the development of society, people's living and working habits have undergone tremendous changes, so various lumbar and cervical diseases occur frequently. Once these diseases occur, they will cause great harm to people's healthy life, so we must do a good job of relevant protection in daily life. It is worth mentioning that there are still many people who do not understand the vertebrae in their bodies, so the following introduces professional knowledge in this area.

Vertebrae are made up of:

The vertebrae include 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 sacral vertebrae and 3 to 5 coccygeal vertebrae. There are 32 to 34 vertebrae in childhood. As we age, five sacral vertebrae fuse into one sacrum, and the coccygeal vertebrae fuse into one coccyx. Therefore, adults generally have 26 vertebrae.

The vertebrae consist of two parts: the vertebral body in front and the vertebral arch in the back.

Vertebrae

The vertebral body is roughly in the shape of a short cylinder, with cancellous bone inside and a thin layer of dense bone outside. The upper and lower vertebrae are connected by cartilage to form a column, which is the main load-bearing part of the vertebrae.

Vertebral arch

The vertebral arch is located behind the vertebral body. The part connected to the vertebral body is called the pedicle. It is slightly thinner and has notches above and below, called the supraspinal notch and infravertebral notch respectively. The infravertebral notch is more obvious. The superior and inferior notches at the pedicles of adjacent vertebrae together form the intervertebral foramen. The posterior part of the vertebral arch is plate-shaped and is called the lamina. The left and right vertebral lamina are connected to form a complete vertebral arch. The vertebral body and vertebral arch together form the vertebral foramen, and the vertebral foramen of each vertebra are connected to form the vertebral canal that runs through the spine to accommodate and protect the spinal cord.

There are seven processes on the vertebral arch: the one extending backward is called the spinous process, most of which can be felt on the midline of the back; there is a transverse process extending on each side, and both the spinous process and the transverse process have ligaments and muscles attached to them; there is a pair of protrusions above and below the vertebral arch, called the superior articular process and the inferior articular process. The upper and lower articular processes of adjacent vertebrae are opposite to each other, and the articular surfaces form articular process joints.

Lumbar spine

There are 5 lumbar vertebrae. The vertebral body is thick and kidney-shaped in cross section. The vertebral foramen is large and triangular, the articular surface of the articular process is almost sagittal, and the spinous process is wide and short, plate-like, and extends almost horizontally backward.

Sacrum

The sacrum is a triangular-shaped bone formed by the fusion of five sacral vertebrae. The protrusion of the front edge of the sacrum base is called the sacral promontory, which is an important sign of obstetric pelvic measurement. There are four pairs of presacral foramina on the front of the sacrum. There are four pairs of posterior sacral foramina on both sides of the median sacral crest behind the sacrum. The anterior and posterior sacral foramina are connected to the sacral canal, through which the anterior and posterior branches of the sacral nerve pass respectively. The sacral canal is the lower part of the vertebral canal, and the foramen at its lower end is called the sacralfiatus. There are downward-protruding sacral horns on both sides of the hiatus. In clinical practice, the sacral horns are often used as landmarks to determine the location of the sacral hiatus for sacral canal anesthesia. The lateral surface of the sacrum has an auricular surface that articulates with the auricular surface of the ilium.

Coccyx

The coccyx is formed by the fusion of 3 to 4 degenerate coccygeal vertebrae. It is connected to the sacrum at the upper end and the free lower end is the tip of the coccyx.