First Cervical spine (C1) is also known as the atlas. The atlas (C1) is the most superior (first) cervical vertebra of the spine. The atlas joint connecting the skull and spine. The atlas(C1) and axis(C2) are specialized to allow a greater range of motion than normal vertebrae. They are responsible for the nodding and rotation movements of the head.
The atlas is ring-shaped and does not have a body and no spinous process, unlike the other of the vertebrae of the spinal column. On the superior surface of the atlas, has a pair of concave facets. The facets articulate with rounded condyles on the underside of the skull’s occipital bone. This junction allows the head to nod up and down. Below the atlas bone is the axis bone (C2). Pivot and gliding joints of the atlas & axis bones allow the head to move side-to-side.
C1 Spine(Atlas)Bony Landmark
The atlas is made up of the anterior and posterior arch, 2 transverse processes, 2 prominent lateral masses and the transverse foramen.
Lateral mass is the thickest part of the bone. This region supports the weight of the skull.
Superior articular facet is an oval-shaped, It articulates with an occipital condyle on the underside skull.
Inferior articular facet is a flattened surface of the inferior lateral mass that articulates with the superior articular facet on the axis (C2).
Transverse process is a notable lateral prominence of the lateral mass. The transverse process serves as an attachment site for muscles that move the head and neck.
The transverse foramen is a hole in the transverse process that serves as a passageway for the vertebral artery and vein.
Vertebral foramen is a large opening in the center of the bone through which the spinal cord passes.
Anterior arch is a band of bone that extends medially from the transverse processes and encloses the anterior portion of the vertebral foramen.
The anterior tubercle is a slight elevation at the apex of the anterior arch. It is an attachment point for the longus coli muscles.
Posterior arch is a narrow band of bone that extends from the transverse processes and encloses the posterior portion of the vertebral foramen.
The posterior tubercle is a slight elevation at the apex of the posterior arch. It is an attachment site for the nuchal ligament and rectus capitis posterior minor muscle.