Atlas (C1) vs Axis (C2)
| Property | Atlas (C1) | Axis (C2) |
|---|---|---|
| Latin Name | Atlas | Axis |
| Type | Bone | Bone |
| Body System | Skeletal | Skeletal |
| Body Region | Spine | Spine |
| Function | The first cervical vertebra that supports the skull. Allows nodding movements (flexion and extension) of the head at the atlanto-occipital joint. | The second cervical vertebra that provides a pivot point for rotation of the head. The dens (odontoid process) projects superiorly and acts as the axis around which the atlas rotates. |
| Clinical Significance | Jefferson fractures (burst fractures of the atlas) result from axial loading. Atlanto-occipital dislocation is usually fatal. Congenital anomalies include atlas assimilation (occipitalization). | Odontoid fractures are common cervical spine injuries, especially in elderly patients. Hangman's fracture involves bilateral pars interarticularis fractures of C2. Atlantoaxial instability occurs in rheumatoid arthritis and Down syndrome. |
| FMA ID | 12519 | 12520 |