Platybasia

Last revised by Assoc Prof Frank Gaillard on 26 Jul 2021

Platybasia is characterized by abnormal flattening of the skull base as defined as a base of skull angle over 143º.

Platybasia alone does not usually cause symptoms unless it is associated with basilar invagination 6.

A number of techniques have been described to measure platybasia 1

  • standard measurement: the angle formed by a line joining the nasion with the center of the pituitary fossa and a line joining the anterior border of the foramen magnum with the center of the pituitary fossa 1
  • modified measurement: the angle formed by a line extending across the anterior cranial fossa to the tip to the dorsum sellae and a line drawn along the posterior margin of the clivus 1
    • adult normal value range: 116°-118°
    • children normal range: 113°-115°

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Figure 1: standard method
    Drag here to reorder.
  • Figure 3: modified method
    Drag here to reorder.
  • Case 1
    Drag here to reorder.
  • Case 2: with osteogenesis imperfecta
    Drag here to reorder.