Suture closure in the human chondrocranium: CT assessment.

PURPOSE: To chronicle the development of ossification centers, sutures, and synchondroses in the chondrocranium throughout childhood by using computed tomography (CT). MATERIALS AND METHODS: One hundred eighty-nine children (age range, newborn to 18 years; median age, 4.0 years) without skull base deformity were referred for cranial CT. The closure of 18 sutures and synchondroses was graded. RESULTS: In the occipital bone at birth, six components were identified. The Kerckring ossicle rapidly fused to the supraoccipital bone within the 1st month. At age 1-3 years, the posterior and anterior intraoccipital synchondroses began to fuse. The occipitomastoidal, petro-occipital, and spheno-occipital synchondroses remained partially open into the teenage years. In the sphenoid bone at birth, 13 ossification centers were identified; most assimilated into the sphenoidal body during the first 2 years. Pneumatization of the sphenoid sinus appeared at age 1-2 years and advanced posteriorly over the next 3-5 years. CONCLUSION: The complex process of skull base development is chronicled, which provides CT standards for judgment of the patterns and timing of sutural or synchondrosal closure.

Postnatal development of the central skull base: normal variants.

PURPOSE: To illustrate the normal variants and developmental anomalies of the skull base on computed tomographic (CT) scans. MATERIALS AND METHODS: One hundred eighty-nine children (age range, newborn to 18 years; median age, 4.0 years) without skull base deformity were referred for cranial CT. Normal developmental variants in the sphenoid and occipital bones were characterized. RESULTS: Sixteen normal variants of central skull base development were identified including anterior foramen in the presphenoid, remnant of the craniopharyngeal canal in the anterior portion of the postsphenoid, rounded defects in the central sphenoid, clefts and fissures along the basiocciput and basisphenoid, basioticum variants, notochordal remnant in the midline of the basiocciput, and fusion variants of the Kerckring ossicle with the supraoccipital portion of the occipital bone. CONCLUSION: The location and CT appearance of the 16 variants and anomalies are related to the known embryologic origin of this region. Recognition of such variants may prove necessary in evaluation of patients with skeletal dysplasias and disorders of skull base development.