Atlas Vertebra or C1
It is the topmost cervical vertebra found in the neck region. This C1 along with C2 forms a joint between the spine and the skull. It is responsible for the movability of the skull. Here, the atlanto-occipital joint helps in the up and down movement of the head. Likewise, the dens (a projection of C2) help in the sideways movement.
C1 is just a ring-like structure with an anterior arch and a posterior arch. It also has two lateral masses carrying articular facets.
Axis Vertebra or C2
C2 or axis is the second cervical vertebra from the top. It is found immediately below the C1. The dens or bony protrusions are the key features in the axis. It usually exhibits constriction when it joins the main vertebra. The axis also has other features like the vertebral foramen, pedicels and laminae. Their vertebral foramen is smaller compared to the atlas.
Explore: Difference between Spinal Cord and Backbone
Difference between C1 and C2
C1 |
C2 |
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It is also known as the atlas vertebra, and is the topmost cervical vertebra. |
It is known as the axis vertebra, and is the second cervical vertebra from the top. |
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Found in between C2 and cranium. |
Found between C3 and C1. |
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It holds the head up-right. |
It has dens that aid the sideways motion. |
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It is just a ring-like structure with no spinous process. |
It has a strong spinous process on the under surface. |
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They have large vertebral foramen. |
They also have large vertebral foramen, but it is comparatively smaller than that of C1. |
Also see: Spinal Cord
Frequently Asked Questions on Difference between C1 and C2
What are cervical vertebrae?
They are the neck vertebrae that are found below the skull. There are a total of seven cervical vertebrae (in mammals) that are followed by the thoracic and lumbar vertebrae. The cervical bones support the skull, protect the spine and also gives the neck a structure.
What is vertebral foramen?
Vertebral foramen is a kind of opening formed by the anterior and the posterior vertebral arch. This foramen starts from C1 and continues till L5 (lumbar vertebra).
What is transverse foramen?
Both C1 and C2 have transverse foramen. It is also an opening like vertebral foramen. But, this opening is filled by the vertebral vein and vertebral artery from C1 to C6. The C7 has only vertebral veins.
Extended Reading : Bones of Spine
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