- Vertebrae Overview
- What is a Vertebrae
- Cervical Vertebrae (C1-C7)
- Vertebrae Anatomy
- Intervertebral Discs
- Vertebral Ligaments
Cervical Vertebral Ligaments
Spinal ligaments can prevent excessive, and damaging, movement through hyper-flexion, and hyper-extension. Ligaments connect bones, cartilage, and other structures to provide support, stability, and strength to the cervical spine. They are made up of fibrous sheets of connective tissue, and three of the key spinal ligaments are the Ligamentum Flavum, and the Posterior and Anterior Longitudinal ligaments. These three ligaments stretch from the Axis (C2) to the sacrum, with the Ligamentum Flavum and the Posterior Longitudinal ligament limiting flexion, and the Anterior Longitudinal ligament limiting extension. The Anterior and the Posterior Longitudinal ligaments also reinforce the front, and back, of the annulus fibrosis of the intervertebral discs respectively. The Ligamentum Flavum also forms a protective layer over the dura mater which is the membrane covering the spinal cord. It connects under the facet joints and creates a small curtain at the back of the vertebral column, in between the vertebrae.
Other key ligaments in the cervical spine include the Alar which stretches from the Axis to the skull and is involved in head rotation and lateral flexion, and the Anterior Atlantoaxial ligament between the Axis and Atlas which limits extension of the neck. Also connecting the Axis and Atlas is the Posterior Atlantoaxial ligament which prevents excessive flexion. Additionally, the Ligamentum Nuchae is a cervical spinal ligament that also controls flexion of the neck. As the neck has a great range of extension, in comparison to lower regions of the spine, the ligament systems in this region are quite complex and work hard to prevent trauma through excessive movement.
Cervical Spinal Ligament Complexes
There are four key complexes of ligaments that support the cervical spine: the Occipitoatlantal Ligament Complex; the Occipitoaxial Ligament Complex; the Atlantoaxial Ligament Complex; and the Cruciate Ligament Complex. From top to bottom of the cervical spine these consist of the:Occipitoatlantal Ligament Complex
Four ligaments stretching between the Occiput (the back of the head) and the Atlas:
- Anterior Occipitoatlantal Ligament
- Posterior Occipitoatlantal Ligament
- Two Lateral Occipitoatlantal Ligaments
Four ligaments stretching between the Occiput and the Axis:
- Occipitoaxial Ligament
- Two Alar Ligaments
- Apical Ligament
Four ligaments connecting the Atlas to the Axis:
- Anterior Atlantoaxial Ligament
- Posterior Atlantoaxial Ligament
- Two Lateral Ligaments
Stabiliziing ligaments supporting the Atlantoaxial complex:
- Transverse Ligaments
- Superior Longitudinal Fascicles
- Inferior Longitudinal Fascicles
Pathology of the Ligaments in the Cervical Spine
Ligaments are made up of fibrous connective tissue, mainly consisting of collagen. The body becomes less efficient at producing collagen as we age, with some estimates putting peak collagen production at around 25yrs old. This creates a problem when extra demands are put on the body through trauma or excessive wear and tear to the ligaments. Ligaments have little blood supply due to their non-vascular nature and, as such, can take a long time to heal, if they do so at all, similarly to intervertebral discs. The blood supply comes from the surface (periosteum) of the bones that they are attached to. This connection sometimes referred to as the fibro-osseus junction, or enthesis, and contains pain receptors. It is this function which is usually torn when a ligament is sprained, rather than the body of the ligament. Partial tears are often more painful than full tears, which may in fact remain painless, as they can be further irritated by movement. A problem which originates in the enthesis of a ligament (or muscle) is called an enthesopathy.
Sprains of the muscles, joints, or ligaments in the cervical spine can cause the tissues to become inflamed which results in neck pain. A protective reflex, occurring in the dorsal horn, where the nearby muscles are put into spasm and become tense, can work to prevent further injury, but may also be a result of faulty signalling, causing pain and a stiff neck. Sensitisation of this kind can cause continual feedback and reinforcement of pain and muscle spasms, further delaying the healing process. This perpetual loop may continue even past the point where the sprained area has healed, making further injury more likely due to muscle contraction. Disrupting this cycle of pain and inflammation is key to relieving chronic neck pain and may involve the use of epidural steroid injections, oral steroids, alternative remedies such as fish oil, or acupuncture/acupressure treatment.
Whiplash, Spinal Ligament Syndrome, and Prolotherapy
Whiplash can cause serious disruption to the neck musculature and the ligaments in the neck, particularly the Anterior and Posterior Longitudinal ligaments. Injury to the fibro-osseous junction of the posterior neck muscles at the point where they connect to the occiput, and injury to the Nuchal, supraspinous, and interspinous ligaments as the attach to the vertebral spinous processes can lead to whiplash associated disorder, chronic neck pain, hypermobility, and further injury potential. Injury to the ligaments connecting to the occipital area can also cause referred pain to the back of the head, the temples, and behind the eyes and may be mistaken for tension headaches resulting in the problematic ligament being ignored and, therefore, untreated.
Spinal ligament syndrome may arise through whiplash or through cervical subluxation putting extra strain on the supporting posterior ligaments. Cervical subluxation can occur in those who suffer with rheumatoid arthritis as the degenerative changes in the facet joints lead to the vertebrae becoming misaligned. This vertebral slippage, which is similar to that which occurs in spondylolisthesis, puts this extra strain on the ligaments in the neck. Spinal ligament syndrome can cause chronic neck pain and restrictions in movement. Radicular pain in the arms and shoulders can also occur due to pinched nerve roots. X-rays and MRI or CT scans can confirm the diagnosis. If instability is due to anatomical irregularities then surgery may be necessary, with the cervical spine being fused to provide support for the damaged ligaments. In some cases an epidural steroid injection may relieve the pain and inflammation and break the cycle allowing the area to heal.
Prolotherapy, also referred to as sclerotherapy and ligament sclerosant therapy, may help to strengthen ligaments and their attachment to the muscles. This treatment is most commonly used for lower back pain and may not be advisable for treating cervical ligaments due to the potential for complications to arise. The treatment involves injecting sclerosant solution around the weakened enthesis which causes a localised inflammatory response and proliferation of fibroblasts. The solution triggers the layering of collage fibers in order to repair the tear, an effect which is thought to continue for about two months after the injection. The advisability of creating, in effect, scar tissue is debatable, but it can help to heal the ligament and restore function, although in some patients the pain may be made worse permanently with no clear mechanism or predictable pattern for this reaction. Patients usually experience worse pain for the first couple of weeks after the injection as the inflammatory reaction is ongoing; analgesic treatment is likely to be administered at the same time as the prolotherapy to help patients cope with the extra pain. Patients may require a ‘top-up’ treatment every few years.
Last Updated: 1/22/2011