The Cervical Spine

Fracture Prevalence
Projections
Lateral Radiograph

The majority of detectable abnormalities will be visible on the lateral film.

Normal convex lines
Pseudosubluxation C2/C3
AP Radiograph
Normal AP
Malalignment spinous processes
Widening spinous processes
Open Mouth Radiograph (C1/C2)
Normal C1/C2
Jefferson burst fracture - C1
Asymmetric widening due to rotation
Mach effect due to overlying incisor   Mach effect - repeat is normal

"Swimmer's" View
Normal swimmer's
Unilateral facet dislocation - nondiagnostic   Unilateral facet dislocation - repeat - diagnostic

Oblique Views
Facet joint dislocation - right oblique   Facet joint dislocation - left oblique   Facet joint dislocation - lateral

Flexion and Extension Views
Normal flexion   Normal extension
RA with atlanto-axial subluxation in flexion   RA with normal alignment in extension

Soft Tissue Structures
Main Ligaments
  • Anterior Longitudinal Ligament
  • This is a taut, strong structure that is closely applied to the anterior aspects of the vertebral bodies and the annulus of the intervertebral discs.

  • Posterior Longitudinal Ligament
  • This is weaker, and is attached to the posterior vertebral bodies and intervertebral discs.

  • Ligamentum Flavum
  • This ligament lines the dorsal surface of the spinal canal and is tightly applied to the laminae.

  • Interspinous Ligaments
  • These interconnect the spinous processes.

  • Supraspinous Ligament
  • Is applied to the dorsal tip of the spinous processes, and overlies the interspinous ligaments.

Intervertebral Discs
  • The intervertebral discs consist of:
    • A central, gelatinous nucleus pulposus.
    • Surrounding peripheral, concentric layers of annulus fibrosis.

Spinal Canal
  • The normal anteroposterior diameter of the cervical spinal canal is approximately 10-20mm. On the lateral film it may be measured relative to the vertebral body - the two should be equal. In the cervical spine region, the spinal cord occupies 50% of the spinal canal.
Pathomechanics of Cervical Spine Trauma
Flexion
  • Up to 80% of all cervical spine injuries are due to hyperflexion.
  • As the head is flexed, the maximum force is focused upon the bodies of C4-C7.
  • Compression of the vertebral body causes anterior wedging.
  • The posterior elements - the spinous processes, laminae and supporting ligaments are placed in tension, which result in fractures and tears of these structures.

Extension
  • Hyperextension creates tension in the anterior longitudinal ligament. This may tear at the intervertebral disc space or at the margin of the vertebral body. The latter results in an avulsion fracture of the anterior superior or inferior margin of the vertebral body.
  • The posterior elements are simultaneously compressed, which may result in fractures of the spinous processes, laminae and facets.

Axial Compression
  • Initial trauma is to the vertebral endplates.
  • Increased compression causes the intervertebral disc to explode into the vertebral body. This creates a comminuted fracture.

Distraction
  • Movement of the head, which weighs approximately 10Ib, creates tensile forces on the cervical spine.
  • If occuring in combination with flexion or extension, this lessens the severity of compression resulting from these forces. Osseous structure will be maintained, to the detriment of the interspinous ligaments.

Rotation
  • The spinal ligaments withstand compression and distraction forces well, but are very susceptible to disruption by rotation.
  • Results also in fractures of the posterior elements, particularly the facets and laminae, and in fracture - dislocations.
Significance of Injury and the concept of stability
Cervical Spine Trauma
Atlas (C1)
Neural arch fracture
Jefferson burst fracture - C1
Axis (C2)
Odontoid peg fracture   Odontoid peg fracture   Odontoid peg fracture
Hangman's fracture - C2
C3-C7
Anterior wedge compression fracture - C7
Unilateral perched facet - C3/C4
Bilateral perched facets - C5/C6
Teardrop extension fracture - C2
Spinous process fracture - C4
Whiplash - reversal of the normal lordosis
Pathology
Fracture C2 with spondylosis   Fracture C2 with spondylosis   Fracture C2 with spondylosis
Metastatic disease C2,C3   Metastatic disease C4
Congenital fusion C2,C3   Congenital fusion C2,C3
Congenital fusion, hypoplastic peg   Congenital fusion, hypoplastic peg

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