Rheumatoid Arthritis
Rheumatoid Arthritis is a systemic disease (affects many areas) caused by the destruction of joint cartilage. This inflammatory process can cause injury to the joints resulting in pain and deformity.. The cervical spine is commonly involved in rheumatoid arthritis. The neck is affected in three ways:
1. Atlanto-axial subluxation = upper levels C1-C2 become unstable.
2. Basilar invagination = second cervical vertebra sticks into the skull.
3. Subaxial subluxation = instability of the vertebra below the top two vertebra in the neck.

Ankylosing Spondylitis
Ankylosing Spondylitits is an inflmmatory arthritis affecting the spine and sacroiliac joints. The spine ossifies (fuses) in a manner that looks like bamboo. (bamboo spine) Spine involvement may be regional (cervical, thoracic, lumbar) or total. With spine involvement, the bone fusion can lead to changes in the normal curves of the spine: the lumbar area looses lordosis (back flattens), the thoracic and cervical area develops increased kyphosis (increase forward bend). Depending on the degree of change in curve and location, different posture abnormalities can occur. Potential posture changes may cause the patient to walk with the head staring at the floor (fused in that position). A genetic marker, HLAB27, is usually positive. Corrective re-positioning of the spine may be necessary in selected cases.

Reiter's Syndrome
Reiter's Syndrome is a condition that follows infection. It has the potential for recurrent episodes of involvement of the spine and sacroiliac joints. The spine may have patchy areas of fusion and the sacroiliac joint is usually involved on one side. Treatment is commonly medical and not surgical. HLAB27, genetic marker, is commonly present.

Psoriasis
A small percentage of patients with the skin disease, Psoriasis, will have involvement of the spine and sacroiliac joint. The spine changes are similar to those found in Ankylosing Spondylitits in the thoracolumbar spine (thoracic and lumbar spine area) and cervical spine but usually do not result in deformity leading to surgical correction. HLAB27, genetic marker, is commonly present.

Gut Associated Arthritis
A small percentage of patients with disease of the intestinal tract (ulcerative colitis and regional enteritis) may involve the lumbar area in a pattern similar to Ankylosing Spondylitis. The sacroiliac joint may be involved and commonly HLAB27 is positive.

D.I.S.H.
Diffuse Idiopathic Skeletal Hyperostosis is a pattern of bone formation that can involve the spine leading to ankylosis (fusion). The bone formation looks like candle wax flowing down the spine. The most common area affected is the thoracic spine, although other areas of the spine can be involved (cervcial).