Congenital Anomalies

Question 1

Platybasia
aka Flat Skull Base
Aka Marin’s Anomaly

Answer 1

• flattening of the angle between the cloves and body of the sphenoid
• often associated with softening disorders
• asymptomatic
• neurological complications of brain stem
• seen on lateral skull radiograph
• Martin’s Basilar Line
  Normal Range: 123-152 degrees
  Platybasia = >152 degrees
  Commonly associated with:
  basilar incarnation, atlas anomalies, occipitalization, block vertebra and Klippel-Feil

Question 2

Basilar Impression

aka Basilar Invagination

Answer 2

• Dens is superior to foramen magnum!
  -cephalic position of the upper cervical vertebra to the base of the skull
• Primary: congenital
• Secondary: acquired with softening disease
• Paget;s osteomalacia, fibrous dysplasia, osteogenesis imperfecta
• RHEUMATOID A. - most common of the arthritides to cause secondary Basilar Impression
• asymptomatic until 3rd and 4th decade
• symptoms: headache, neck stiffness, brainstem dysfunction,
• 25% of cases may have congenital and acquired disease of he the vertebral arteries at he cranio-vertebral junction
• can be mistaken for MS
• lat fil
• election of the floor of the posterior fossa, an upward convexity of the posterior aspect of the former magnum, and cephalic migration of the odontoid are the main findings
  -occurs in conjunction with:
  occipitalization
  atlantoaxial instability
  acquired laxity of transverse ligament