M01.04.003 Cervical Spine

The cervical spine is the uppermost portion of the vertebral column, situated between the cranium and the thoracic vertebrae. It consists of seven vertebrae, with two being uniquely named: the atlas (C1) and the axis (C2). This article explores the anatomy of these vertebrae, their characteristic features, joints, ligaments, and clinical relevance.

Key Points to Remember

The cervical spine consists of 7 vertebrae.
The atlas (C1) has no vertebral body and articulates with the occiput and the axis.
The axis (C2) contains the dens (odontoid process), essential for head rotation.
Special joints and ligaments are present in the cervical spine, contributing to its mobility.

Characteristic Features of Cervical Vertebrae

The cervical vertebrae are distinguished by several unique features:

Feature	Description
Triangular Vertebral Foramen	A characteristic of cervical vertebrae, providing space for the spinal cord.
Bifid Spinous Process	The spinous process splits into two at its distal end.
Transverse Foramina	Holes in the transverse processes for the passage of the vertebral artery, vein, and sympathetic nerves.

Atlas and Axis: Unique Features

Atlas (C1)

Articulation: Articulates with the occipital condyles of the cranium and the axis (C2).
Unique Features:
- No vertebral body or spinous process.
- Contains lateral masses connected by an anterior and posterior arch.
- The anterior arch has a facet for articulation with the dens of the axis.
- The posterior arch has a groove for the vertebral artery and C1 spinal nerve.

Axis (C2)

Key Feature: Contains the dens (odontoid process), which projects superiorly and articulates with the atlas.
Function: Allows head rotation independent of the torso.
Articulations:
- Lateral atlanto-axial joints: Between the inferior articular facets of C1 and the superior facets of C2.
- Medial atlanto-axial joint: Between the dens of C2 and the facet of C1.

Joints of the Cervical Spine

Joints Present Throughout the Vertebral Column

Joint Type	Description
Intervertebral Joints	Cartilaginous joints between vertebral bodies connected by intervertebral discs.
Facet Joints	Synovial joints formed by superior and inferior articular processes.

Joints Unique to the Cervical Spine

Joint	Description
Atlanto-Axial Joint (x3)	Includes lateral and medial atlanto-axial joints between C1 and C2.
Atlanto-Occipital Joint (x2)	Between C1 and the occipital condyles, allows head flexion (nodding).

Ligaments of the Cervical Spine

Ligaments Present Throughout the Vertebral Column

Ligament	Description
Anterior and Posterior Longitudinal Ligaments	Support vertebral bodies and discs.
Ligamentum Flavum	Connects adjacent vertebrae at the lamina.
Interspinous Ligament	Connects spinous processes of adjacent vertebrae.

Ligaments Unique to the Cervical Spine

Ligament	Description
Nuchal Ligament	Extends from C1 to C7, providing attachment for muscles like the trapezius.
Transverse Ligament of the Atlas	Anchors the dens of C2 to the atlas.

Anatomical Relationships

The cervical spine is intimately associated with several neurovascular structures:

Transverse Foramina: Passage for the vertebral artery, vein, and sympathetic nerves.
Spinal Nerves: These exit from above their respective vertebrae, except for C7, which has nerves extending both above and below.

Clinical Relevance

Common Injuries to the Cervical Spine

Injury	Cause	Description
Jefferson Fracture	Vertical fall onto an extended neck	Lateral masses of the atlas fracture, but spinal cord injury is unlikely due to the large vertebral foramen.
Hyperextension Injury (Whiplash)	Rear-end traffic collision or sudden head movement	Causes damage to ligaments and fractures in severe cases, potentially leading to spinal cord involvement.
Hangman’s Fracture	High-velocity hyperextension	Fracture of the pars interarticularis of C2, often lethal due to spinal cord rupture.
Fracture of the Dens	Trauma to C2	Can result in unstable fractures, potentially leading to avascular necrosis or spinal cord injury.

M01 Human Anatomy

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