The odontoid of the second cervical vertebrae (ie: the axis) forms a joint with the anterior ring of the first cervical vertebrae (ie: the atlas). This joint is primarily responsible for allowing the head to rotate from side to side as if you were nodding "no" to someone. See the related link for further information.
There is rotation of head around the dens of the axis. Dens is actually derived from the body of the atlas vertebra.
The Atlas is designed to allow a nodding movement, whilst the axis below it has the odontoid peg on it to allow shaking, or rotational movement of the skull.
The atlas and axis bones are found in the neck region of the spine, known as the cervical spine. The atlas bone is the topmost cervical vertebra that holds up the skull, while the axis bone is located just below the atlas and allows for rotational movement of the head.
The Atlas
The atlas vertebra supports the head and allows for the rocking motion of the occipital condyles, which helps facilitate nodding of the head up and down. This unique structure allows for a greater range of motion in the neck.
The atlas is the very top vertebra in your spine. The head or skull rests on it, and is allowed to move in many directions. The atlas sits upon the axis vertebra - between them, they allow much more rotational movement than do other vertebrae. Also, the actual brain stem extends down into the atlas/axis pair. The spinal cord begins at the bottom of the axis bone.
There is rotation of head around the dens of the axis. Dens is actually derived from the body of the atlas vertebra.
The joint between the atlas (C1) and the occipital bone that allows for the "yes" movement (nodding the head) is classified as a condyloid joint. This type of joint permits flexion and extension, allowing the head to tilt forward and backward. The articulation between the rounded condyles of the occipital bone and the superior articular facets of the atlas facilitates this movement.
The movement is called rotation, where the head pivots around the axis of the neck to enable movement from side to side. This movement primarily involves the atlas and axis vertebrae at the top of the spine.
The atlas vertebra (C1) controls the rotation of the head from left to right, while the axis vertebra (C2) allows for nodding or shaking of the head up and down. Together, these vertebrae form the upper cervical spine, which is responsible for a significant portion of head movement.
The movement of turning the head from side to side is called rotation. This movement occurs at the joint between the first two cervical vertebrae, known as the atlas and axis. Rotation of the head allows for increased range of vision and flexibility in everyday movements.
The Atlas is designed to allow a nodding movement, whilst the axis below it has the odontoid peg on it to allow shaking, or rotational movement of the skull.
The atlas and axis bones are found in the neck region of the spine, known as the cervical spine. The atlas bone is the topmost cervical vertebra that holds up the skull, while the axis bone is located just below the atlas and allows for rotational movement of the head.
The Atlas
When Perseus, a Greek hero, took a mosters head and showed it to Atlas, the Titan god who holds up the sky. Atlas took one look at the head and, since it was so ugly, turned to stone. The head was the head of Medusa. Since Atlas was so big he turned into the Atlas mountain range.
Articulation of the head.
The atlas vertebra supports the head and allows for the rocking motion of the occipital condyles, which helps facilitate nodding of the head up and down. This unique structure allows for a greater range of motion in the neck.