Vertebral body

the portion of the vertebra consisting of the centrum, the ossified neurocentral joint and part of the vertebral arches, and the facets for the heads of the ribs. The joints of the vertebral bodies include the intervertebral discs. Also, see cervical spine, thoracic spine, lumbar spine.

2. Pathology

The vertebral body is involved in numerous musculoskeletal disorders.

Total aplasia of the vertebral body sometimes occurs; alternatively, lack of development of a portion of the bone produces a lateral or posterior hemivertebra. Frequently this anomaly is associated with fusion or segmentation defects in the vertebral arch. Some congenital abnormalities of vertebral body shape include central constriction with hypoplasia where the two chondral ossification centres join (butterfly vertebra); nonsegmentation of two or more vertebral somites (block vertebra); a waistlike constriction of a rudimentary structure at the level of the intervertebral disc (hourglass appearance). Characteristic abnormalities of vertebral shape are observed in osteoporosis, including wedge-shaped vertebrae and compression (pancake vertebral body). A burst fracture affects both the anterior and the posterior portions of the vertebral body Both wedging and compression in osteoporosis indicate a fracture of the vertebral body. Other abnormalities in shape of vertebral bodies are listed under the topic vertebra.

Scalloping of vertebral bodies is characterized by exaggerated concavity of the posterior surface, which may result from different causes. Scalloping is seen in a variety of disease processes.

The shiny corner sign is an abnormality of the spine characterized by increased radiodensity of the corners of vertebral bodies as a consequence of osteitis. This appearance is seen on radiographs of patients with ankylosing spondylitis.

Squaring of vertebral bodies, which occurs in patients with ankylosing spondylitis or ulcerative colitis, involves straightening or formation of a convex anterior margin of a vertebral body as a result of erosion and new bone formation.

Osteoporotic deformity of the vertebral body may lead to a biconcave shape of the intervertebral disc, termed discal ballooning.

In skeletal metastasis, destruction or collapse of vertebral bodies may be the presenting manifestation, but this abnormality is evident also in osteoporosis, osteomalacia and plasma cell myeloma. A biopsy ultimately is required for accurate diagnosis in many patients. Sclerosis of the vertebral body may result in the development of an entirely radiodense vertebral body (ivory vertebral body); this finding is particularly common in carcinoma of the prostate but may also occur in lymphomas and, rarely, chordoma, plasmacytoma and Paget's disease.

Delayed post-traumatic collapse of vertebral bodies is termed Kummells disease. The length of time between the traumatic episode and the vertebral collapse may range from days to years. The principal sites of involvement are the lower thoracic and upper lumbar vertebral bodies. Gas collections may be observed within the collapsed vertebral body (vacuum vertebral body) and may extend into the adjacent psoas musculature.

Segmental sclerosis of vertebral bodies is an idiopathic disorder that may be observed in some patients who develop increased radiodensity of peridiscal vertebral bone without a specific cause. Radiographic features include bone lysis, bone sclerosis, or both. A hemispheric band of sclerosis extends for a variable distance from the anterior and inferior margins of the vertebral body to its central portion. Other findings may include narrowing of the intervertebral disc space and involvement of the adjacent vertebral body.

Displacement of a portion of the intervertebral disc into the vertebral body (Schmorl's node) produces a contour defect that can be apparent in many disorders.

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