Foramen magnum stenosis in homozygous achondroplasia.

A 4-month-old female with homozygous achondroplasia and daytime apnea was found to have a small foramen magnum by computerized tomography. Following suboccipital craniectomy and C1-C2 laminectomy respiratory problems did not recur during a 7 month post-operative period. We suggest that the respiratory problems in homozygous achondroplasia may be due to brainstem compression from an abnormally small foramen magnum.