Article Figures & Data
Figures
- FIG 1.
CM-1. Sagittal T2WI of the cervical and upper thoracic spine (A) shows cerebellar tonsillar herniation below the foramen magnum, with syringohydromyelia (arrows). Axial T2WI at C4 (B) and T5 (C) levels demonstrate syringohydromyelia.
- FIG 2.
CM-1.5. Sagittal T1WI and T2WI of the cervical and upper thoracic spine (A and B) show obex herniation below the foramen magnum, with medullary kink (arrowhead).
- FIG 3.
CM-2. Sagittal T2WI of the brain (A) shows cerebellar tonsillar herniation below the level of the foramen magnum (arrow), hydrocephalus (asterisk), tectal beaking, and towering of the cerebellum. Axial and sagittal T2WIs of the lumbar spine (B and C) show myelomeningocele with neural placode exposure (arrowheads) and CSF flow artifacts (asterisk).
- FIG 4.
CM-2. Sagittal T1WI of the brain (A) shows hypoplasia of the splenium of corpus callosum (asterisk) and tonsillar parenchymal loss secondary to the herniation (arrowhead), scalloping of the clivus (short arrow), and dysplastic sella (gray asterisk). Axial T2WIs (B and C) show interdigitating gyri (white arrows in B) due to fenestrated falx, stenogyria (gray arrowhead), and hypoplasia of the splenium of the corpus callosum (white arrows in C).
- FIG 5.
Phase-contrast MR imaging: CSF flow study. Phase images in systole and diastole (A and B) show decreased CSF flow posterior to the cerebellum and the dorsal subarachnoid space (arrowheads).
- FIG 6.
Intraoperative photographs show posterior fossa decompression in a patient with CM-1. A, After a midline incision in the occipitocervical region, the occipital bone, the atlanto-occipital membrane, and the C1 lamina are exposed. B, A suboccipital craniectomy and removal of the posterior arch of C1 has been performed, and the dura mater will be opened in a Y-shaped fashion. C, After opening of the dura mater and the arachnoid overlying the cisterna magna, the 2 cerebellar hemispheres with their respective cerebellar tonsils can be visualized. D, A duraplasty has been performed, wherein a dural graft has been inserted and sutured in a watertight fashion to enlarge the cistern.
