Spinal stenosis and cervical spondylosis – This means that the spinal canal is narrowed. This is usually because the joints that are between the vertebrae, called the facet joints, have hypertrophied (become larger) secondarily to osteoarthritis of these joints. At the same time the ligament that runs inside the spinal canal, the ligamentum flavum, has also hypertrophied and is pushing on the nerves. The third component that causes spinal stenosis is the pressure from degenerative discs that push into the spinal canal.
Facet joint hypertrophy – This is when the joints between the vertebrae become large and irregular. This is because the joints are damaged by arthritis (osteoarthritis).
Annular tear – This describes the condition where the intervertebral disc has early damage. The damage comprises of a tear in the annulus fibrosus (see the section Anatomy of the Spine). The tear causes different inflammatory substances to be released by the body and this can cause local neck pain, referred pain and even radiculopathy (see the section Cervical Slipped Disc).
Disc bulge – This describes the condition where the nucleus pulposus (see the section Anatomy of the Spine) starts to bulge through the damaged annular fibres.
Disc herniation/disc extrusion – Both these terms mean that a portion of the nucleus pulposus has now extended outside of the confines of the annular fibres into the spinal canal (see the section Cervical Slipped Disc).
Broad-based disc herniation – This is where the disc is damaged extensively and there is usually a decrease in the height of the disc and the disc looks a bit like a flat tyre with the whole or a large part of the nucleus projecting beyond the confines of the annular fibres.
Foraminal disc herniation – In this case the disc herniation is on the side of the spinal canal where the nerve roots leave the spinal canal through the foramina. Even relatively small disc prolapses or hernias can cause a lot of pain or even weakness, as the space is very restricted in this area.
Extraforaminal disc compression – In this instance the nerve is compressed outside of the spinal canal and outside of the foramen as it leaves on its way to the arm. This is usually caused by a broad-based disc herniation.
Central disc herniation – This is where the disc herniation is in the middle of the spinal canal. Since this is a fairly large space, the disc herniation needs to be fairly large compared with a foraminal disc prolapse before symptoms occur. In some cases the spinal canal is already partly occluded by facet joint hypertrophy and compression from the ligament inside the spinal canal – the ligamentum flavum – and even small disc herniations can cause symptoms in these cases. Large central disc herniations can damage the spinal cord and cause myelopathy (spasticity) secondary to spinal cord damage.
Flattening of the spinal cord – This is a description of the situation that occurs when a herniated (slipped or prolapsed) disc has extended so far into the spinal canal that it is pushing on the spinal cord.
Nerve root – This is the nerve root that leaves the spinal cord and exit the spine through the intervertebral foramen. Most of the exiting nerve roots can be seen side-on in the axial planes and in the coronal planes and are seen end-on in the sagittal plane.
Foraminal stenosis – This is a narrowing of the foramen and the exiting nerve root can become compressed in the foramen by either a disc herniation or a hypertrophied facet joint or a combination of both.
Spondylolisthesis – This is the term that describes a slip of one vertebra on the one directly below and is secondary to a weakness in the bone that supports the facet joints that keep the spine stable.
Spondylolysis – This is frequently the cause of spondylolisthesis and is the process where the bone supporting the facet joints is weak and fractured.
Spondylosis – This is spinal degeneration and is characterised by bone spurs (osteophytes) that develop on the vertebral bodies and are usually asymptomatic, except if they compress nerves.