Ring fibers (Ringbinden; Spiral Annulets) & Sarcomere disorientation

NADH stain

H&E stain

Congo red stain
Ring fibers
  • Stains
    • NADH & AMPDA: Ring of striations, perpendicular to normal orientation, around circumference of muscle fiber
    • H & E: Internal, ring-shaped, dark-staining regions; Often in smaller fibers
    • Congo red: "Amorphous" ring in a muscle fiber with paler central region
  • Clinical correlations
    • Poorly defined
    • Associated disorders

NADH stain

AMPDA stain

NADH stain
  • Dark staining sarcoplasmic pad around rim of fiber (Right)

Ring Fiber
  Circumferential sarcomeres around normally oriented sarcomeres
  Sarcoplasm with abundant Mitochondria surrounds most of fiber
  Lipofuscin granule (Top left)

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