akzessorische Ossikel des kraniozervikalen Übergangs

akzessorische Ossikel des kraniozervikalen Übergangs

Craniovertebral junction (CVJ) anomalies can be congenital, developmental or due to malformation secondary to any acquired disease process. These anomalies can lead to cranial nerve compression, vertebral artery compression and obstructive hydrocephalus.

Pathology

The craniovertebral junction is formed by the occipital condyles, atlas (C1), axis (C2) vertebrae and their articulations. Any process which can give rise to malformation of these structures, may result in CVJ anomaly. It can be due to congenital, developmental or acquired cause.

On this basis of etiology, CVJ malformations can be classified as:

Congenital anomalies and malformations

Malformations of the occipital sclerotome

• remnants of proatlas
• platybasia
• occipital condylar hypoplasia
• condylar dysplasia (condylus tertius, paracondylar process, and basilar process)
• segmentation anomaly of the clivus
• atlas assimilation

Malformations of atlas vertebra

• atlas assimilation
• bifid arches
• aplasia and hypoplasia of the atlas

Malformation of axis and odontoid process

• atlantoaxial fusion
• persistent ossiculum terminale
• os odontoideum
• odontoid dysplasia

Developmental and acquired malformations

Malformations at foramen magnum

• basilar invagination

  • osteogenesis imperfecta

  • acro-osteolysis

  • rickets

  • hyperparathyroidism

  • Paget disease of bone

• stenosis of foramen magnum

  • achondroplasia

  • paramesial invagination

Atlantoaxial instability

• infections

  • tuberculosis

  • Grisel syndrome

• trauma

• inborn errors of metabolism

  • Morquio syndrome

  • mucopolysaccharidosis

• Down syndrome

• neoplastic

  • osteofibroma

  • chordoma

  • neurofibromatosis

  • eosinophilic granuloma

• other

  • fetal warfarin syndrome

  • syringomyelia

  • Conradi syndrome