Myotube-like structures were seen in extraocular and limb muscles in an adult with centronuclear myopathy. The limb-muscle fibers were very small and were of a uniform histochemical type. Extrajunctional acetylcholine receptors were not seen with immunoperoxidase stains, and ultrastructurally normal neuromuscular junctions were seen in the extraocular-muscle samples. Further studies on developing muscle are needed to identify possible mechanisms of arrest of muscle maturation.

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Vertebral artery occlusion due to spontaneous rotation of the head with resultant cerebellar infarction and acute hydrocephalus occurred in a 9½-month-old child. The clinical and radiological findings are described, and a brief review of the literature is given.

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A myopathy restricted to the diaphragm was found in an infant who died at 3 months of age of respiratory failure due to immobility of the diaphragm. Grossly, the diaphragm was thin and translucent. On microscopical examination few muscle bundles were seen. Most muscle fibers were small, and numerous necrotic fibers with large sarcolemmal nuclei, focal cytoplasmic basophilia, and hyaline or homogeneous eosinophilic degeneration in the center of the fibers were seen.