The 31 vertebrae are actually organized into segments of the vertebral column, which is comprised of: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. They are important because each segment innervates a dermatome via a spinal nerve.
Vertebral Segments
Here's a breakdown of the 31 segments of the vertebral column:
| Region | Number of Vertebrae |
|---|---|
| Cervical | 8 |
| Thoracic | 12 |
| Lumbar | 5 |
| Sacral | 5 |
| Coccygeal | 1 |
| Total | 31 |
Cervical Vertebrae
- There are 8 cervical vertebrae located in the neck region.
- They support the head and allow for neck movement.
- The first two cervical vertebrae (atlas and axis) are specialized for head rotation.
Thoracic Vertebrae
- There are 12 thoracic vertebrae located in the chest region.
- They articulate with the ribs to form the rib cage.
- They provide support for the chest cavity and protect internal organs.
Lumbar Vertebrae
- There are 5 lumbar vertebrae located in the lower back.
- They are the largest and strongest vertebrae, bearing the most weight.
- They allow for flexion and extension of the lower back.
Sacral Vertebrae
- There are 5 sacral vertebrae located at the base of the spine.
- They are fused together to form the sacrum, which connects the spine to the pelvis.
- They provide stability and support for the pelvic girdle.
Coccygeal Vertebrae
- There is 1 coccygeal vertebra, located at the very end of the spine.
- It is commonly known as the tailbone.
- It provides attachment points for certain muscles and ligaments.
Clinical Significance
Each segment of the vertebrae is associated with a spinal nerve that innervates a specific area of the skin, called a dermatome. Understanding the segmented structure of the vertebral column is important in diagnosing and treating spinal conditions.
