Today, let's examine the bones that make up the spine. We call them vertebrae. They are somewhat irregular yet they stack on top of one another to form the scaffolding required for additional joints to branch off supporting our extremities. The brain transmits signals through the spinal cord to the branching nerves to the designated tissues. Another role of the spine is to house the spinal cord allowing protection of the delicate nerves. The segmented nature of the spine allows for bending and twisting allowing mobility and flexibility. If you see pictures or diagrams of the spine from the side, you will notice curvatures through the neck, upper back and the low back region. These curvatures are called "lordosis" and "kyphosis". They help the spine absorbs shocks and compressional forces.
The human spine is made up of 33 vertebrae stacked on top of one another. These are grouped into five regions based on their location and function:
Cervical Spine (Neck):
Comprises 7 vertebrae (C1–C7).
Supports the head and allows for its wide range of motion.
Notable vertebrae include:
Atlas (C1): Holds the head and enables nodding.
Axis (C2): Facilitates rotation of the head.
Thoracic Spine (Upper Back):
Comprises 12 vertebrae (T1–T12).
Attached to the rib cage, providing stability and protection for vital organs like the heart and lungs.
Less flexible than other regions.
Lumbar Spine (Lower Back):
Comprises 5 vertebrae (L1–L5).
Bears most of the body’s weight, making it larger and stronger than the cervical and thoracic vertebrae.
Sacral Spine (Pelvis):
Comprises 5 fused vertebrae (S1–S5).
Forms the back of the pelvis and connects the spine to the hips through the innominate bone.
Coccyx (Tailbone):
Comprises 4 fused vertebrae.
Acts as an attachment point for ligaments and muscles.
The bones at each region differ from a counterpart at another region. Bones in the same region tend to share similar characteristics as well. However, the common traits they share is that they have a body where the intevertebral disc sits on. The pedicle forms a bridge where it connects the body to the back portion of the vertebrae. The transverse processes stick out at the sides. They allow for the connection to the ribs. Lastly, pointy structure is formed through the lamina on each side to form the spinous process.
There are additional joints called facets which allow for connection to the next verterbrae above and/or below. The superior articular facet aligns with the inferior articular facet of the vertebrae above whilst the inferior articular facet aligns with the superior articular facet of the verterbrae below. This joints happen both on the left and right side as well.
So you will notice that each verterbae stack on one another through the discs at the front portion and lines up the facets on the back portion.
The vertebrae are the unsung heroes of the human body, providing the foundation for movement, support, and protection. While they are designed to withstand a lifetime of use, they are not immune to wear and tear. By understanding their structure and function and practicing healthy habits, you can ensure that your spine remains strong and resilient for years to come!
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