(2) Injuries. In either of the instances mentioned in the previous paragraph,
the sudden excessive compression drives the weight of the head and thorax against the
lumbar spine while the sacral spine is driven upward. Driving injuries often cause axial
b. Flexion, Extension, Rotation.
(1) Definition. Flexion is the act of bending or the condition of being bent.
Extension is movement by which the two elements of any jointed part are drawn away
from each other. Rotation is movement of the body about the body's axis. These spinal
cord injuries occur when the spine moves past its normal range of motion.
(2) Injuries. Injuries caused include bone damage, tearing of muscles and
ligaments, and tearing of the spinal cord.
(a) Flexion-rotation injuries. These injuries can occur at any level of
the spinal cord. Usually, flexion-rotation injuries involve the cervical area, particularly
C5 and C6. The cervical vertebrae can be dislocated by a sudden impact, the impact
shearing supporting ligaments and blood vessels.
(b) Forced extension (hyperextension) injuries. In this injury, the head
is sharply thrust back, and the upper spinal segments hyperextend (that is, these
segments are extended beyond their normal limits). Such an accident can disrupt
support ligaments, rupture intervertebral disks, and fracture one or more pedicles
(vertebrae stem). The result is that the spinal cord is compressed and destabilized. An
example is a person falling face down on stairs he is climbing up. The force to the head
or chin thrusts the head back sharply, intervertebral disks rupture, vertebral bodies
fracture, and supporting ligaments are damaged.
c. Lateral Bending.
Definition. The head and neck are bent to one side, beyond normal
Injury. Lateral bending can cause significant injury to the cervical spine.
Definition. Distraction is the pulling apart of the spine.
(2) Injury. This pulling apart stretches and tears the spinal cord. An
example of distraction as a mechanism of injury is suicide by hanging. Gunshot wounds
to the chest, back, and abdomen may also cause distraction type injury to the spinal