primary basilar invagination
MONDO:0007188Mondo
Findings
No curated finding names primary basilar invagination yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Primary basilar impression (PBI) is a very rare skeletal developmental defect characterized by congenital upward translocation of the upper cervical spine and clivus into the foramen magnum. PBI can be asymptomatic or associated with severe neurological dysfunction.
Definition from the Mondo Disease Ontology (MONDO:0007188), read 2026-09-29. CC BY 4.0.
Features
8 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Abnormal vertebral morphologyHPOHP:0003468
- Very frequent (80% to 99% of cases)
- Abnormality of the cervical spineHPOHP:0003319
- Very frequent (80% to 99% of cases)
- Basilar impressionHPOHP:0005758
- Very frequent (80% to 99% of cases)
- PlatybasiaHPOHP:0002691
- Very frequent (80% to 99% of cases)
- Short neckHPOHP:0000470
- Very frequent (80% to 99% of cases)
- Abnormality of eye movementHPOHP:0000496
- Frequent (30% to 79% of cases)
- Abnormality of the pharynxHPOHP:0000600
- Frequent (30% to 79% of cases)
- Abnormality of the voiceHPOHP:0001608
- Frequent (30% to 79% of cases)
Where it sits
Other names
1 name
Resolves to: primary basilar invagination
- Also called
- Bull-Nixon syndrome