Where the atlas (c1) sits in the skeleton
The atlas is the first cervical vertebra (C1), at the top of the spine. It is a ring with no vertebral body; it carries the skull through its joint with the occipital bone, where nodding happens. It is made of an anterior arch, a posterior arch and two lateral masses. The hollows on top of the lateral masses meet the occipital condyles, the inner face of the anterior arch meets the dens of the axis, and the transverse ligament of the atlas holds the dens from behind.
Frequently asked questions
Which part of the skeleton is the atlas in?
The atlas is one of the bones of the vertebral column. Seven cervical, twelve thoracic and five lumbar vertebrae and the sacrum are stacked to support the trunk and enclose the spinal cord.
How many vertebrae are there?
The spine has 24 separate vertebrae. From the top there are seven cervical (neck), twelve thoracic (upper back) and five lumbar (lower back) vertebrae, followed by the sacrum and the coccyx.
Which bones are above and below the atlas?
Above the atlas is the occipital bone of the skull, and below it is the axis (C2).
Why does the atlas have no body?
During development the part that would have become its body joins the axis below and becomes the dens. The atlas is left as a ring.
Other bones of the vertebral column
- Axis (C2)
- Third cervical vertebra (C3)
- Fourth cervical vertebra (C4)
- Fifth cervical vertebra (C5)
- Sixth cervical vertebra (C6)
- Seventh cervical vertebra (C7)
- First thoracic vertebra (T1)
- Second thoracic vertebra (T2)
- Third thoracic vertebra (T3)
- Fourth thoracic vertebra (T4)
- Fifth thoracic vertebra (T5)
- Sixth thoracic vertebra (T6)
- Seventh thoracic vertebra (T7)
- Eighth thoracic vertebra (T8)
- Ninth thoracic vertebra (T9)
- Tenth thoracic vertebra (T10)
- Eleventh thoracic vertebra (T11)
- Twelfth thoracic vertebra (T12)
- First lumbar vertebra (L1)
- Second lumbar vertebra (L2)
- Third lumbar vertebra (L3)
- Fourth lumbar vertebra (L4)
- Fifth lumbar vertebra (L5)
- Sacrum
Joints of the atlas
Compare with similar bones
Bone counts
By region
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