Cervical spine
The cervical region is the most mobile section of the spine, consisting of 7 vertebrae (C1–C7). It carries a head weighing 4–5 kg, ensures its turns, bends and nods, and also protects the vertebral arteries and the cervical spinal cord.
Features of the cervical vertebrae
The cervical vertebrae differ from the thoracic and lumbar vertebrae:
- Small body - minimal load
- Holes in the transverse processes - for the vertebral arteries
- Bifid spinous processes (C3–C6)
- Uncinate processes (processus uncinatus) - form uncovertebral joints
Atlant (C1)
The first cervical vertebra is radically different from all the others - it has no body and spinous process. Atlas is a ring of anterior and posterior arches connected by two massive lateral masses.
Atlanto-occipital joint is a paired joint between the condyles of the occipital bone and the superior articular fossae of the atlas. Provides nodding movements (flexion-extension of the head) with an amplitude of about 25°.
Axis (C2)
The second cervical vertebra has a unique odontoid process (dens) - a vertical pin that fits inside the ring of the atlas.
Atlantoaxial joint - the atlas rotates around the axis tooth, providing 50% of the total volume of head rotation (about 45° in each direction). The tooth is held in place by the transverse atlas ligament. Rupture of this ligament (due to injury) can lead to compression of the spinal cord and instant death.
Vertebral arteries
The vertebral arteries pass through the foramina in the transverse processes of C6–C1, then bend around the lateral masses of the atlas and enter the skull. They provide 30% of the blood supply to the brain (hindbrain, cerebellum, brainstem).
Sharp turns of the head can theoretically compress the vertebral arteries, especially with atherosclerosis.
Vertebra C7 (vertebra prominens)
C7 has the longest unbifurcated spinous process, which can be easily palpated on the back of the neck. It serves as an anatomical landmark during examination.
Clinical significance
- Whiplash - sudden flexion and extension of the neck during an accident
- Cervical radiculopathy - compression of a nerve by a hernia (pain in the arm, numbness in the fingers)
- Cervical myelopathy - compression of the spinal cord (weakness in the arms and legs)
Knowledge of the anatomy of the cervical spine is critical for neurosurgeons and traumatologists; an error at the C1–C2 level can cost the patient his life.
You can study the atlas, axis and other cervical vertebrae in three-dimensional space in the Humio application - rotate the model and track the course of the vertebral arteries.