basilar invagination

• dens projects into base of skull
  • McGregor's line > 4.5 mm
  • Chamberlain's line > 3 mm

• may --> obstructive hydrocephalus

• 1' anomalies of occiput, atlas, axis
• softened bone: rickets / osteomalacia, Paget's dz
• fibrous dysplasia
• dysostoses: OI, achondroplasia, cleidocranial dysostosis

Cf: platybasia

© 2002, C.E. Kahn, Jr.
2002-04-18