What is Vertebrae in Human Body?
The spine or backbone consists of 26 small bones or vertebrae. It is also known as the vertebral column.
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The vertebral column is a part of the axial skeleton, which comprises the skull, ribs and sternum other than the vertebral column. The notochord present in the embryonic stage is replaced by the vertebral column.
The spine forms the main framework of the trunk. It is dorsally placed and attached to the base of the skull.
Each vertebra has a central hollow portion, which forms the neural canal through which the spinal cord passes. The spine protects the spinal cord.
Spine or Vertebral Column Anatomy
Our spine consists of twenty-six vertebrae. In the human body, there are 33 vertebrae in total, but the five sacral and four coccygeal vertebrae are fused together, so taken as one each. The upper twenty-four spine bones are separated from each other by an intervertebral disc between them.
The upper twenty-four vertebrae bones are movable and the rest are fused. Vertebrae anatomy of each region is unique and has different structure and functions.
Read more: What is vertebra?
The spine or the vertebral column bones is divided into five parts. The bones of the spine are named according to the regions, e.g. cervical vertebrae are named as C1, C2, C3, etc. Thoracic as T1, T2, etc. Lumbar as L1, L2, and so on.
- Cervical- 7 vertebrae (C1 to C7)- The first vertebra, C1 or Atlas articulates with the two occipital condyles of the skull. It allows the maximum movement of the neck. It is responsible for the ‘yes’ movement of the head.- The C2 and C1 joints allow the ‘no’ movement of the head.
– It supports the weight of the head.
Also check: How many bones are there in the human neck?
- Thoracic- 12 vertebrae (T1 to T12)- Vertebrae of the thoracic region have limited movement and provide support to the rib cage and protect the lungs and heart. 12 pairs of rib bones articulate with the thoracic vertebrae on the posterior side.
- Lumbar- 5 lumbar (L1 to L5)- Lumbar vertebrae support the weight of the body.- They are larger in size and help in carrying heavy objects.
- Sacral- 1 (fused 5 vertebrae, S1 to S5)- The five sacral vertebrae are fused together.- They connect the vertebral column to the hip bones and form pelvic girdle along with them.
- Coccygeal- 1 (fused tailbone)- The four bones of the coccyx region fuse together to form the tailbone.
The number of vertebrae in each section of the spinal column is calculated using the “vertebral formula.” The number of cervical vertebrae is 7, whereas the number of thoracic vertebrae is 12, the number of lumbar vertebrae is 5, and the number of sacral vertebrae is 5. The sacrum and coccyx have between 3 to 5 vertebrae each, respectively. The formula is C7T12L5S5C3−5=33−35.
The hollow cavity formed by the central portion of each vertebrae bone forms the spinal canal. It encloses the spinal cord and provides protection.
There are various ligaments, which help in the movement and holding vertebrae together.
Structure of Vertebrae
Labelled diagram of vertebral column or spine is given below.
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Frequently Asked Questions
What are the 26 bones of the spine called?
The 26 bones of the spine are called vertebrae. The first 5 bones of the spine are known as the cervical vertebrae, the next 12 bones are known as the thoracic vertebrae followed by 5 lumbar vertebrae and then one fused sacral and a coccyx at the last.
What are the 5 sections of the spine?
The 5 sections of the spine from the top to bottom are:
How many vertebrae do humans have?
There are in total 33 vertebrae (individual bones) present in the spine of children. Some of the spine bones at the lower part get fused during development. The adult human spine consists of 26 bones.
What are the 4 main functions of the spine?
The 4 main functions of the spine are:
- It protects the spinal cord.
- It supports the head.
- It provides the point attachment to ribs and muscles at the back.
- It provides structural support and helps in locomotion and movement.
What is the name of the first two bones of the spine?
The name of the first bone of the spine is Atlas and the second bone of the spine is known as Axis. They are the first two cervical vertebrae.
What type of joint is present between the bones of the spine?
The adjacent bones of the spine are joined together by cartilaginous joints. This type of joint allows limited movement of bones.
What is the joint between the atlas and axis called?
The joint between the atlas and axis is called a pivot joint.
What is the difference between spinal cord and vertebral column?
The vertebral column, a bony, segmented structure that supports the head and thorax, is one of the main components of the central nervous system, which also includes the spinal cord. The vertebral column holds the spinal cord, protected by the vertebral column.
Define caudal vertebrae and spinal cord vertebrae.
The bones that comprise a vertebrate’s tail are known as caudal vertebrae. Depending on the animal’s tail size, there may be a few to fifty caudal vertebrae. They are known as the coccygeal vertebrae in humans and other tailless vertebrates. They range from three to five and are fused to form the coccyx.
The spinal canal comprises 33 stacked vertebrae, which are tiny bones that make up the spinal cord vertebrae. The vertebral column is a tunnel that contains and safeguards the nerves and spinal cord from injury. To enable a range of motion, the majority of vertebrae move. The sacrum and coccyx are the lowest vertebrae and are fused, so they cannot move.
Which bones of the spine are attached to ribs?
Thoracic vertebrae are connected to ribs.
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