Atlas (C1) vs Axis (C2)

特性	Atlas (C1)	Axis (C2)
ラテン語名	Atlas	Axis
種類	Bone	Bone
器官系	Skeletal	Skeletal
身体部位	Spine	Spine
機能	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.
臨床的意義	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

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Full structure pages

Atlas (C1)

Atlas

Ring-shaped and unusual in lacking both a vertebral body and a spinous process, the atlas is the first cervical vertebra and supports the skull. Its structure consists of anterior and posterior arches joined by two …

Skeletal Spine

Axis (C2)

Axis

The second cervical vertebra, the axis provides the pivot around which the head rotates. Its defining feature is the dens, or odontoid process, a tooth-like projection that extends superiorly from the body to articulate with …

Skeletal Spine