Some of the most common injuries associated with car collisions occur in the neck, often alongside related head and back injuries. Like any injury stemming from a car collision, neck injuries can run the gamut in terms of severity —from minor soft tissue injuries to serious nerve and spine complications.
To understand car collision neck injuries, you have to know something about the anatomy of your spine. The neck consists of the top 7 vertebrae (bones) of the spine also known as the cervical spine. The bones are identified by the letter C (as in cervical) and then the number of the bone, counting from the top. So, C3 is the third cervical vertebrae from the top. Below the 7 cervical vertebrae, beginning at the bottom of the neck, are 12 thoracic vertebrae to which the ribs in the back attach. They are identified by the letter “T” and the number of the bone, counting from the top.
Below the thoracic vertebrae, beginning in the low back area, are the 5 lumbar vertebrae (L1 through L5), then the sacrum (S-1) and then the coccyx. If the bones of the spine were simply stacked on top of each other, your spine would be inflexible. You couldn’t bend over, twist or make other movements of your spine. Flexibility exists because of spongy discs that are between each bone in the spine. The discs allow for movement and act like a shock absorber to cushion the bones of the spine as you twist, jump and move your spine.
Discs are sometimes analogized to jelly donuts. The outer part, which is actually called the annulus fibrosis, holds in the “jelly,” which is called the nucleus pulposus. In addition to the bones and discs, the spine includes the surrounding soft tissues—muscles, ligaments, tendons, blood vessels and nerves.
Let’s briefly look at the nerves.
The spinal cord originates at the brain and travels down the spinal canal. As it descends, the spinal cord gives off smaller nerves that leave the spine between each vertebra through an opening called the foramen.
The nerves that leave the spine in the cervical area travel into the arms and hands. The nerves that leave the spine in the thoracic area mostly go into the chest and stomach. The nerves that leave the spinal canal in the lumbar spine area travel into the legs and feet. So, to return to the neck, it consists of the first 7 vertebrae, C1 through C7, the discs between them—which are identified by the two bones that they are between, as in C4 – C5, and the surrounding muscles, ligaments, tendons, blood vessels and nerves. The top 2 cervical discs, called the atlas (C1) and the axis (C2), differ from the other vertebrae because they are designed specifically for rotation. These two vertebrae allow your neck to rotate in so many directions, including looking to the side.
Though the cervical spine is very flexible, it is also at risk for injury from strong, sudden movements, such as whiplash-type injuries. This high risk of harm is due to the limited muscle support in the cervical area, and because this part of the spine has to support the weight of the head. This is a lot of weight for a small, thin set of bones and soft tissues to bear. Therefore, sudden, strong head movement can cause damage.
Let’s look at the most common types of traumatic car crash neck injuries.
Neck sprain. Ligaments are bands of fibrous tissue that connect bones together and help to stabilize joints. When those ligaments are stretched or torn in the neck, the result is a neck sprain, which can cause pain and stiffness.
Neck strain. There are also muscles in the neck. When those muscles are stretched or torn, a neck strain results. Sometimes, these are called “pulled muscles.” They often occur when the muscles are suddenly and powerfully contracted or when they stretch unusually far.
Neck sprains and neck strains are sometimes called “hyperflexion-hyperextension injuries” or “whiplash.”
Cervical Radiculopathy (pinched nerve).
Cervical nerves leave the spinal cord in the cervical spine area and travel down into the arm. Along the way, the nerves supply sensation (feeling) to a part of the skin of the shoulder and arm and supply electrical signals to certain muscles to move part of the arm or hand. When a nerve is irritated or pinched, by either a bone spur or a fragment of a herniated (ruptured or torn) disc, it causes the nerve to not work properly. The result can be weakness in the muscles the nerve goes to, numbness in the skin where the nerve goes, or pain in the area where the nerve travels. These radiating symptoms are called cervical radiculopathy.
Shearing forces from a motor vehicle collision can overcome the normal structural integrity of the disc and a herniated disc may result. Sometimes these are called “slipped discs” or “ruptured discs.” In this injury, the annulus is torn and part of the nucleus pulposus squeezes out of the center of the disc. In the jelly donut analogy, the jelly comes out of the donut. If the tear is on the side of the disc next to the spinal canal, the nucleus pulposus can press against the spinal nerves. This pressure can cause pain, numbness and weakness along the nerve. There is also evidence that the chemicals released from the ruptured disc may irritate the nerve root, leading to some of the symptoms of a herniated disc, especially pain.
Symptoms of Neck Injuries
After a car collision, it’s not always obvious that you’ve injured your neck. That can be owing to the surge of pain-masking adrenaline and endorphins that many people experience after a collision, but also because damage to the neck can manifest in other areas of the body, such as your arms and hands. Common symptoms of neck injuries include:
- pain in your neck
- pain in your shoulders, arms or hands
- reduced range of motion in your neck
- numbness, weakness and slower reflexes in your arms and hands, and
- muscle spasms in your neck.