Next, the car seat springs forward causing the driver’s whole torso to move forward at a high velocity. Physics defines velocity as “rapidity or speed of motion; swiftness.” Keep in mind as your seat moves forward your head is still moving back. This action is similar to the final moment before a spring releases.
Then, almost instantaneously your torso and head are flung forward. This forward motion is so strong that if the driver does not have their seat belt on they could, depending on force of impact, be thrown right out of their seat into the steering wheel or even through the window. This strong forward action causes the driver’s whole spine to flex forward often past their physiological limits. This action can cause a considerable amount of posterior neck, mid-back, shoulder, and even low back damage.
Common areas of damage as the head is thrown forward:
o Facet joints - These joints are the most commonly injured joints in the neck.
Posterior Muscles and Nerves
· Group of back muscles that runs beside the vertebrae in an almost vertical direction.
· These neck extensors are commonly injured during whiplash accidents.
o Rectus Capitis Posterior Minor muscle
· Individuals with chronic neck pain exhibit muscle atrophy of this muscle as seen of MRI. This can be caused by trauma or compression of the first cervical branches of the spinal nerves (C1 dorsal ramus). This compression occurs because of entrapment within the rectus capitis posterior major muscle.
· Atrophy of this muscle and C1 injury causes symptoms such as: suboccipital headaches with radiation of pain behind the eyes, dizziness, and benign positional vertigo (BPV). With BPV you will feel a sudden sensation of movement, or spinning, when you move your head or hold it in certain positions.
NEUROGENIC ATROPHY OF SUBOCCIPITAL MUSCLES AFTER A CERVICAL INJURY: A Case Study American Journal of Physical Medicine & Rehabilitation, Volume 77(6) November/December 1998, pp 545-549 Andary, Michael T. MD; Hallgren, Richard C. PhD; Greenman, Philip E. DO; Rechtien, James J. DO, PhD
o Suboccipital Triangle – This is an area in the neck at the base of the skull surrounded by the following three muscles
o All of the suboccipital muscles are extremely important as they contain very high levels of muscle spindle fibers. Muscle spindles provide postural information to the central nervous system. Damage to these structure in experimental animals cause gait disturbances and ataxia (an inability to coordinate voluntary muscle movements)
o The Suboccipital nerve supplies input to the muscles of the suboccipital triangle. Compression of this nerve can occur at the superior oblique muscle.
· The greater occipital nerve is located directly under the Semispinalis Capitis. Compression of this nerve is one of the causes of cervicogenic headaches, these are referred to as occipital neuralgias.
§ Occipital neuralgia is a medical condition characterized by chronic pain in the upper neck, back of the head, and behind the eyes. This is sometimes known as C2 neuralgia or Arnold’s neuralgia.
§ Research has shown that about 85% of patients with whiplash injuries have trigger points in the Semispinalis Capitis muscle.
A Distinct Pattern of Myofascial Findings in Patients After Whiplash Injury Archives of Physical Medicine and Rehabilitation Volume 89, Issue 7, July 2008, Pages 1290-1293
· This neck extensor is commonly injured in whiplash injuries.
Luo Z, Goldsmith W. Reaction of a human head/neck/torso system to shock. Journal of Biomechanics 1991;24(7):499-510
· The spinalis cervicis muscle is not present in everyone (inconsistent muscle). Orginates from a ligament in the lower neck (ligamentum nuchae).
· The is some research showing the cervical multifidus msucle can cause increased loading of the joint capsule surrounding the joint in the neck (collision-induced loading of facet capsular ligaments).
· These deep posterior muscles are often injured during whiplash accidents.
Are cervical multifidus muscles active during whiplash and startle? An initial experimental study Gunter P Siegmund, Jean-Sébastien Blouin, Mark G Carpenter, John R Brault, and J Timothy Inglis BMC Musculoskelet Disord. 2008; 9: 80. Published online 2008 June 5. doi: 10.1186/1471-2474-9-80
o Trapezius (upper fibers)
· The third occipital nerve travels under the trapezius muscle until it pierces this muscle and ends up in the lower part of the head (occiput). Compression of this nerve causes occipital neuralgias.
See Part 4 – Resolving Whiplash Injuries with Active Release to review symptoms of whiplash Injuries and treatment strategies.
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