Cervical spine

Cervical spine consists of 7 bones from C1 to C7. C1 and C2 are called atypical cervical vertebrae.

Stable fracture: Vertebral components will not be displaced by normal physiological loads after injury

Unstable fracture: Vertebral components will displace further d/t serious disruption of the structures jeopardizing the spinal cord

The function of Disk:

• Binds vertebrae together
• Allows motion
• Absorbs shock
• Distributes loads between the segment
• Contributes lordosis
• Comprises approximates 25% of the total length of the spinal column

50 % of flexion and extension of the neck in Occiput and C1

50 % of rotation of neck in C1 and C2

Abnormal cervical spine prevertebral soft tissue swelling:

At C1: >10 mm

At C3,C4 : >7 mm

At C5, C6, and C7 : >20 mm

Basion-Dens Interval (BDI): <12mm (distance between the odontoid tip and the distal end of  basion)

Basion Posterior Axial Line Interval ( BAI): <4mm – anterior to basion; <12mm posterior to the basion

Lateral Atlas Dens Interval (LADI):

• Within 2mm

Commonly injured: C1-2, C5-7 (Jeffersons)

                             : C2 and C5 (Meyers)

Mechanisms of Spinal Injuries

1. Avulsions/ Tractional Injury:

In cervical spine—>7^th spinous process can be avulsed [Clay-Shovellers’ fracture]

In lumbar spine—> may avulse transverse process

2. Direct Injury:

Penetrating injury

3. Indirect Injury:

(most common)

Fall from height—> Spinal column collapse on its vertical axis

Insufficiency fractures occur due to minimal force in the bone which is weakness by osteoporosis/pathological lesion

Imaging of the cervical spine

Open mouth view:

For C1 and C2

AP/Lateral:

Look for 4 parallel line

In lateral view:

          Forward shift of vertebral body by 25% —>unilateral facet dislocation (Bow-tie Sign)

          Forward shift of vertebral body by 50% —> Bilateral facet dislocation

If lateral view fails to visualize injury–>Swimmmer’s View –> fails CT scan

Distance between Odontoid –> Post. the aspect of ant. Arch of atlas

No more than 3 mm in adults, 5 mm in child

Soft tissue shadow: < 5mm (above the level of the trachea) and less than 1 vertebral body’s width thickness below

Diagnostic pitfall in children

1. ↑ atlantodental Interval: Up to 5 mm is (N) in child

2. ↑ Retropharyngeal Space: Can be d/t crying

3. SCIWORA: Spinal Cord Injury Without Obvious Radiological Abnormality

Injuries to Occiput – C1-C2 complex

1. Occipital condyle Fractures
2. Occipito-atlanta dislocation
3. Atlas fracture
4. Atlanto-axial rotator subluxation and dislocation
5. Fracture of odontoid process (Dens)
6. C1 lateral Mass Fracture
7. Traumatic Spondylolisthesis (Hangman’s fracture)

Details of cervical spinal injuries