C2 extension teardrop fractures are avulsion fractures with an intact anterior longitudinal ligament displacing and anteriorly rotating the anteroinferior vertebral body fragment. The avulsed fragment's vertical dimension equals or exceeds its transverse dimension, and focal and minimal prevertebral soft-tissue swelling usually is present. This type of fracture tends to occur in elderly patients with osteoporotic bone. As the name implies, this type of fracture is the result of extension forces.
C2 extension teardrop fractures tend to be stable, and usually are not directly responsible for spinal cord injury. These fractures are extremely rare and differ in many aspects from flexion teardrop fractures that are more common of the lower C-spine. Although lower C-spine teardrop fractures can result from extension forces, they usually result from severe flexion forces.
These fractures are unstable and are associated with anterior cord syndrome (quadriplegia; loss of pain, touch, and temperature sensations, but with retention of posterior column functions—proprioception and vibration), secondary to impingement of the cord by the hyperkyphotic vertebral segment or, more commonly, by retropulsion of C2 into the canal. C2 extension teardrop fractures are associated with traumatic spondylolisthesis of C2.
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Odontoid type II fracture
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Atlantooccipital and atlantoaxial dissociation
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Hangman fracture
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Three types of C2 odontoid fractures: type I is an oblique fracture through the upper part of the odontoid process; type II is a fracture occurring at the base of the odontoid as it attaches to the body of C2; type III occurs when the fracture line extends through the body of the axis.
