Читать книгу Anatomy of bone system. The manual for medical students / Анатомия костной системы. Учебное пособие для медицинских вузов - Г. И. Ничипорук - Страница 23

Anomalies and developmental defects may be classified according to the following criteria:

I. Vertebral size anomalies:

1. Microspondylia – reduction in size of one or more vertebrae.

2. Brachyspondylia – reduction in width of one or more vertebrae.

3. Platyspondylia – flattening of some vertebrae which get a truncated cone shape.

4. Macrospondylia – increase in size of some vertebrae.

II. Slit-like Defects of Vertebrae:

1. Splitting of vertebral bodies (anterior splitspine, spina bifida anterior) – a slit-like defect of the vertebral body located more often in the sagittal plane.

2. Splitting of the vertebral arch (posterior split spine, spina bifida posterior) – a slit-like defect of the vertebral arch (near a spinous process or on its place).

3. Spondylolysis – in this case, the vertebral body is not fused with the pedicles of the vertebral arch: this anomaly may be observed either on one or on both sides, it happens most often in the V lumbar vertebra or in the I sacral vertebra; in case of bilateral spondylolysis, the posterior part of the arch with the inferior articular processes are separated from the pedicles of the arch with the superior articular processes.

4. Spondylolisthesis – displacement of the body of the upper vertebra frontwards (very seldom – backwards relative to the lower vertebra. Most often it occurs after compressive fracture of a vertebral body when the vertebra becomes wedge-shaped.

5. Rachischisis – in this case the vertebral body is not fused with the pedicles of the vertebral arch, and the vertebral arch is splitted.

III. Development anomalies of individual vertebrae:

1. Assimilation of the atlas:

– atlanto-occipital assimilation (occipitalization) – partial or complete fusion of the I cervical vertebra with the occipital bone: two-sided (symmetric) or one-sided (asymmetric);

– atlantoaxial assimilation – partial or complete fusion of the I and II vertebrae.

2. Manifestation of the atlas (formation of the occipital vertebra – proatlas) –inclusion of the atlas particles into the occipital bone which is manifested in the presence of anomalous bony prominences in the circle of the great (occipital) foramen.

3. Kimmerle`s anomaly – transformation of the vertebral artery groove on the atlas into the canal as a result of formation of a bony outgrowth above this groove.

4. Development anomalies of the II cervical vertebra:

– agenesia (absence) of the dens;

– the dens and the body of the II cervical vertebra are not fused together.

5. Thoracolisation of the cervical vertebrae – formation of cervical ribs (most often from the VII cervical vertebra).

6. Sacralisation – fusion of the V lumbar vertebra with the I sacral vertebra: there are 4 vertebrae in the lumbar part of the vertebral column; the sacrum consists of 6 vertebrae.

7. Lumbarisation – the I sacral vertebra and the II sacral vertebra are not fused together: there are 6 vertebrae in the lumbar part of the vertebral column; the sacrum consists of 4 vertebrae.