Whiplash Injuries of The Head and Neck
Whiplash injury of the head and neck is caused by a sudden exaggerated thrust of the head backward, forward, and sometimes sideways. Abnormal forces are applied to muscles, ligaments, nerves, bones, intervertebral discs, blood vessels, and eyes as the head moves beyond normal physiological limits. There may be no visible bruises or abrasions from this type of injury, yet victims report classic symptoms. These symptoms result from injuries to vertebrae and to soft tissues of the head and neck.
Hyperflexion
The head is propelled in a forward and downward motion in hyperflexion. A wedge-shaped deformity of the bone may be created if the anterior portions of the vertebrae are crushed. Intervertebral discs may be damaged. The discs may bulge or rupture, irritating spinal nerves.
Hyperextension
The head is forced backward in hyperextension. Pieces of bone may be pulled from cervical vertebrae by a tear of the anterior longitudinal ligament. Spinous processes of the vertebrae may be fractured. Intervertebral discs may be compressed posterioly and torn anteriorly. Vertical arteries may be stretched, pinched, or torn, causing reduced blood flow to the brain. Nerves of the cervical sympathetic chain may also be injured.
Spinal Ligaments & Ligament Damage
Vertebrae are held in place by a complex arrangement of ligaments. Some of the ligaments are barely a centimeter long, and all are only a few millimeters thick. In a whiplash injury, ligaments may be badly stretched, partially torn, or completely ruptured as shown in the image below.
The anterior longitudinal ligament, running vertically along the anterior surface of the vertebrae, may be injured during hyperextension. The posterior longitudinal ligament, running on the posterior surface of the vertebral bodies, may be injured in hyperflexion. The broad ligamentum nuchae may also be stretched or torn.
Muscle Injury
Whiplash can cause injuries of neck muscles, ranging from minor strains and microhemorrhages to severe tears. Commonly affected muscles include the sternocleidomastoid muscle, scalene muscles, splenius capitis muscle, and longus colli muscle.
Spinal Cord Injury
When tears occur in ligaments that surround the vertebrae, the vertebrae may slip out of normal alignment and the spinal cord may be injured. An injured spinal cord can cause paralysis and even death. Whiplash may also jar the brain, producing minute hemorrhages on its surface. The esophagus may even be injured as it scrapes against sharp edges of arthritic bone or is pinched between vertebrae.
