What is a Cervical Herniated Disc?

What is a herniated cervical disc?
The spine is composed of a series of connected bones called "vertebrae." The vertebrae surround the spinal cord and protect it from injury. Spinal nerves branch off from the spinal cord, which carries messages from the brain, and carry signals to the upper limbs. The messages carried by the spinal nerves allow the muscles of the arms and hands to contract and the skin of the upper limbs to have sensation to touch, temperature, and vibration.

The vertebrae are connected by an intervertebral disc, analogous to that found between the vertebrae of the lumbar spine, and two small joints called "facet" joints. The disc, which is comprised of strong connective tissues which hold one vertebra to the next, acts as a cushion between the vertebrae. The disc and facet joints allow for movements of the vertebrae and motion of the cervical spine. Without the discs, our cervical spines would be a single column of bone which would not allow for the essential motions associated with our daily postures and activities.

The disc, often described as a “hard version of a jelly donut” is made of a tough outer layer called the "annulus fibrosus" and a gel-like and fluid filled center called the "nucleus pulposus." The cervical discs are not as large as those found in the lumbar spine, and the fluid filled nucleus is not as prominent. Additionally, as we age, the center of the disc cervical discs typically, and perhaps more notably than in the lumbar spine, lose water content, making the disc less effective as a cushion. As a disc degenerates, the outer layer, the annulus, can also wear with tears developing in this outer shell. This can allow displacement of the disc’s center (a herniated or ruptured disc) through an opening or fissure in the outer layer. This herniation of disc material can then result in compression of an exiting spinal nerve, resulting in both mechanical and chemical irritation of the neural tissue. The resulting symptoms can include debilitating pain, numbness, tingling, or weakness in the neck, shoulder, arm, hand, and possibly the axilla and chest. These symptoms result in a syndrome sometimes referred to as “sciatica of the arm.” The medical term for this condition is “cervical radiculopathy.”

The physiatrists of Long Island Spine Rehabilitation Medicine are often consulted for this particularly painful and debilitating syndrome. It is our experience, perhaps due to the involvement of the shoulder region and upper limb, that these cervical syndromes can be particularly disabling for patients. Fellowship trained physiatrists are proficient in performing a particularly detailed neurological and musculoskeletal examination in patients with herniated cervical discs and radiculopathy. The purpose of such an examination is to quantify the extent, if any, of neurological compromise resulting from the injury and to carefully rule out any contributing or mimicking musculoskeletal processes which might complicate the clinical picture. Rarely, the herniated disc may put pressure directly upon the centrally located and descending spinal cord. Symptomatic spinal cord compression is a more critical clinical situation, referred to as “cervical myelopathy,” which can be associated with loss of power and sensation in both the upper and lower limbs.

How is it diagnosed?
The physiatrists of Long Island Spine Rehabilitation Medicine perform a detailed history and physical examination, which includes an assessment of the distribution of pain and sensory disturbance, a complete assessment of upper limb strength, as well as an assessment of upper limb reflexes. Often, through such an approach, the exact spinal nerve affected by a herniated disc can be identified. Other times, due to the variations in our “wiring” and overlap in the functions provided by neighboring cervical spinal nerves, the identification of the affected spinal nerve may remain less clear.

The diagnosis of cervical radiculopathy can be confirmed by advanced imaging of the cervical spine in the form of either computed tomography (CT) scans or magnetic resonance imaging (MRI). X-ray images can show bone spurs, loss of disc space height, and narrowing of the neural foramen or “tunnels” through which the spinal nerves travel. X-rays, or “plain films / radiographs,” cannot show soft tissues such as disc herniations, the spinal nerves, or the spinal cord of the cervical spine. The CT and MRI scans provide more detailed pictures of each of the structures of the cervical spine and can identify most disc herniations. Additionally, electrical studies of the nerves, also referred to as nerve conduction studies or EMG (electromyography) studies may be performed in an effort to detect evidence of nerve damage that can result from a disc herniation. In addition, and in particular with syndromes affecting the upper limbs, such testing can help to rule out a non-spinal process such as a nerve entrapment , i.e. carpal tunnel syndrome at the wrist or ulnar neuropathy at the elbow, which might mimic or complicate a primary cervical process.

The physiatrists of Long Island Spine Rehabilitation Medicine have completed extensive training in performing these studies and are either board certified in electrodiagnostic medicine or board eligible for subspecialty certification in neuromuscular medicine. In our practice, these tests are performed with the latest diagnostic equipment and in a fashion which maximizes patient comfort.

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