Vertebrae Bones, Diagram and Features (original) (raw)
Last Updated : 23 Jul, 2025
**Vertebrae are a collection of bones which are found in all vertebrate animals. We have intervertebral discs that connect the 33 different-sized bones that make up our spinal column. Lumbar (5), sacral (1-fused), coccygeal (1-fused), cervical (7), and thoracic (12) are the five regions that make up the spinal column.
These 33 bones make up the region where the human cranium ends, and the coccyx begins in this group. The vertebrae provide structural support and protection to the spinal cord and enable flexibility and movement of the spine, allowing for various body motions.
Table of Content
- Definition of vertebrae
- What is Vertebrae?
- Diagram of Vertebrae
- Components of vertebrae
- Types of Vertebrae
- Function of vertebrae
Definition of vertebrae
**Vertebrae are the collection of bones that make up the vertebral column in every vertebrate species that protect the spinal cord and provide structural support, allowing for flexibility and movement.
What is Vertebrae?
The vertebral or spinal column and the fluid surrounding it are enclosed by the human backbone. The vertebral cord of the human body is made up of 33 bones which are irregular in size and are connected by one other by intervertebral discs. Vertebrae are small, round bones that make up the backbone. Each vertebra has many projections for articulation and muscle attachment, in addition to a hole where the spinal cord passes through. The names of the vertebrae, or the backbone of humans, are derived from the positions they hold within the vertebral column. The following are the names of the bones that comprise the human spine:
- Seven cervical vertebrae (C1 to C7)
- Twelve thoracic vertebrae (T1 to T12)
- Five lumbar vertebrae (L1 to L5)
- Sacral vertebrae (S1 to S5 fused)
- Coccyx or tailbone (3 to 4 fused bones)
Diagram of Vertebrae
The diagram of the vertebrae showing its different parts are as follows:
Components of Vertebrae
The components of a typical vertebra are the posterior neural arch, also known as the vertebral arch, and the vertebral body, which consists of a massive anterior centrum. The body's rough, flattened surfaces—both upper and lower—make it simple for the intervertebral discs to connect to them. The pedicles and laminae make up the vertebral arch. Each side of the body has two pedicles that connect to form the arch. The lamina, which runs from each pedicle to the middle and back, completes the vertebral arch.
The vertebra gives rise to seven processes, which are projections from tissues:
- The four articular processes
- A single spinous procedure
- There are two transverse processes.
**Also Read: What is the Difference between Backbone and Spinal Cord?
Types of Vertebrae
There are several different types of vertebrae found within most vertebrates, named for the parts of the body they are located in:
Cervical Vertebrae
Situated just behind the skull, the cervical vertebrae constitute the initial segment of the vertebral column. They have the following features:
- C1 to C7 are the names of the cervical vertebrae; C1 is the one nearest to the skull, and C7 is the one further away towards the spine.
- It is a real rib because each process has a vertebral foramen, or hole, through which the spinal cord, vertebral arteries, and vertebral veins pass.
- Atlas (C1) and axis (C2) are the highest vertebrae. The first cervical vertebra, the atlas, is shaped like a ring and lacks a spinous process and vertebral body. It establishes a link between the spine and the cranium.
- The second cervical vertebra, or axis, rotates the atlas and serves as a pivot.
- On the skin's surface, the long, conspicuous spinous processes of vertebra prominens, or C7, are clearly apparent.
- The vertebrae C3 through C6 are small and have wide sides.
- The joint between the atlas and axis of the skull moves mostly because of the cervical vertebrae.
Thoracic Vertebrae
The thoracic vertebrae form the second segment of the vertebral column present between the cervical and lumbar vertebrae. They have the following features:
- The numbers T1 through T12 represent the twelve thoracic vertebrae.
- The lumbar vertebrae continue to grow towards each other despite their intermediate size.
- Costal facets are a defining aspect of the thoracic vertebrae.
- The anteroposterior part of the vertebral body is large and shaped like a heart.
- These vertebrae's facets are helpful for articulating with the ribs.
- The spinous processes have a triangular form and are long.
Lumbar Vertebrae
They have the following features:
- The largest bones in the vertebral column are the lumbar vertebrae. The lumbar area is made up of five bones, designated L1 through L5.
- The lumbar vertebra's wide, kidney-shaped vertebral body is located on the sidewalls of the bone.
- Compared to the other two sections that extend at a perpendicular angle from the body, the spinous process is shorter and thicker.
- With its greatest vertebral body and transverse processes, the L5 is the largest bone in the entire vertebral column.
Sacral Vertebrae
They have the following features:
- The five sacral vertebrae are referred to as S1 through S5.
- In humans, these five bones combine to form a single, big, triangular bone between the ages of 18 and 30.
- The sacral bone is located between the two pelvic wings at the upper rear of the pelvic cavity, at the base of the vertebral column.
- There are four articulations of the sacral vertebrae: two on either side of the hip bones, one with the coccygeal vertebrae, and one with the last lumbar vertebrae.
Coccygeal Vertebrae
The term "tailbone" is frequently used to describe the coccyx or coccygeal vertebrae. They have the following features:
- It consists of three to five segments that come together to create a single structure.
- It has transverse and articular processes, as well as a simple vertebral body.
- It is devoid of spinous processes, laminae, and pedicles.
- Since it serves as a crucial point of attachment for numerous pelvic ligaments and tendons, the coccyx has a significant purpose.
**Also Read: Human Skeletal System
**Function of Vertebrae
A complex network of bones, joints, nerves, muscles, ligaments, and tendons that are interwoven to produce a powerful structure is the spinal column. A group of vertebrae make up this spinal column. The functions of these vertebrae include support, protection, mobility, and more.
- **Functions of the cervical vertebrae: They support and facilitate the head's movements (left-to-right and up-down). Additionally, it has eight pairs of spinal neurons that supply innervation to the hand, neck, shoulder, and arm areas.
- **Thoracic vertebrae functions: The thoracic vertebrae anchor the rib cage and support the neck. It also aids in the force transfer from the torso to the lower back. Twelve pairs of spinal nerves, which regulate different motor and sensory inputs, are located there.
- **Functions of the lumbar vertebrae: It shields the sacrum, coccyx, and cauda equina, a bundle of lower spinal nerves. It regulates leg mobility in addition to supporting and stabilizing the upper body.
- **Sacrum and coccyx: The sacrum and coccyx make up the pelvic and hip's rear wall. Additionally, it makes sitting, walking, and running easier.
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