Limb Muscles: Control
![](../pics/biopsy/control/limb/nlhemp.jpg)
H&E stain
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Fiber size: Mild variation
Myonuclei: Dark-stained; Normally present at periphery of muscle fibers
Endomysial connective tissue: Normal
Capillaries, Endomysial: Small, Between muscle fibers
![](../pics/biopsy/control/limb/nlhehp.jpg)
H&E stain
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![](../pics/biopsy/control/limb/nlcr.jpg)
Congo red stain
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![](../pics/biopsy/control/limb/nlgtmp2.jpg)
Gomori trichrome stain
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2 fiber types: Type 1 muscle fibers have darker, more punctate cytoplasm
Connective tissue: Stains Green
Lipid membranes: Stain red
![](../pics/biopsy/control/limb/nlgthp2.jpg)
Gomori trichrome stain
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![](../pics/biopsy/control/limb/nlvvg.jpg)
VvG stain
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Perimysium: Contains connective tissue with irregular fibrils & intermediate-sized vessels
Muscle fibers: Mildly varied size; Peripheral nuclei
Endomysial capillaries: Between muscle fibers; Often contain nucleated endothelial cells
![](../pics/biopsy/control/limb/nlvvghp.jpg)
VvG stain
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Internal architecture
![](../pics/biopsy/control/limb/nlnadh.jpg)
NADH stain
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Normal Intermyofibrillar Network
Stained structures: Sarcoplasmic reticulum; Mitochondria
Type 1 muscle fibers: Darker stained
Subsarcolemmal staining
Increased in regions of some muscle fibers
Reflects neighboring endomysial capillaries
![](../pics/biopsy/control/limb/nlnadhp1.jpg)
NADH stain
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Fiber Types
ATPase pH 9.4
![](../pics/biopsy/control/limb/nlatp94.jpg)
ATPase pH 9.4 stain
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Type 1 fibers: Intermediate color
Type 2 fibers: Dark color
ATPase pH 4.6
![](../pics/biopsy/control/limb/nlatp46lp.jpg)
ATPase pH 4.6 stain
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Type 1 fibers: Dark color
Type 2A fibers: Pale
Type 2B fibers: Intermediate color
![](../pics/biopsy/control/limb/nlatp46.jpg)
ATPase pH 4.6 stain
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ATPase pH 4.3
![](../pics/biopsy/control/limb/nlatp43hp.jpg)
ATPase pH 4.3 stain
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Type 1 fibers: Dark color
Type 2A fibers: Pale
Type 2C fibers (Immature; Abnormal) (Below): Intermediate color
![](../pics/biopsy/control/limb/2catp43lp.jpg)
ATPase pH 4.3 stain
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ATPase may also stain endomysial capillaries
![](../pics/biopsy/control/limb/2catp43.jpg)
ATPase pH 4.3 stain
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Muscle Fiber Types: Ultrastructure
Muscle Fiber Types: 1 (Right); 2 (Left)
Z-lines (Dark arrow): Thicker
Mitochondria (Light arrow): More
Lipid bodies: More
Glycogen granules: Fewer
NOTES: Image below also shows
2 atrophic muscle fibers in the center
Alkaline phosphatase stain
![](../pics/biopsy/control/limb/nlalp.jpg)
Alkaline phosphatase stain
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Endomysial vessels
Some penetrating vessels, more in a few areas than others, stain for alkaline phosphatase
Small endomysial capillaries do not normally show staining
![](../pics/biopsy/control/limb/nlalpvess.jpg)
Alkaline phosphatase stain
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Acid phosphatase stain
Red, subsarcolemmal staining of regions with lipofuscin: More with increasing age
![](../pics/biopsy/control/limb/nlacp2.jpg)
Acid phosphatase stain
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Esterase stain
![](../pics/biopsy/control/limb/nlest2.jpg)
Esterase stain
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Neuromuscular junctions: Dark red regions on muscle fiber surface, normally contain 1 or 2 segments
![](../pics/biopsy/control/limb/nlesthp.jpg)
Esterase stain
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Mitochondrial Stains
Cytochrome Oxidase (COX)
![](../pics/biopsy/control/limb/nlcoxmp.jpg)
COX stain
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Normal
Fiber types
Type 1: Dark
Type 2: Intermediate or Pale
Staining pattern: Punctate
Mitochondrial disease
Dark staining: Due to mitochondrial proliferation, or
Pale staining: Due to reduced COX synthesis
![](../pics/biopsy/control/limb/nlcoxhp.jpg)
COX stain
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Succinate Dehydrogenase (SDH)
![](../pics/biopsy/control/limb/nlsdhmp.jpg)
SDH stain
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Fiber types
Type 1: Dark
Type 2: Intermediate or Pale
Staining pattern: Reticular & Punctate
Mitochondrial disease: Dark staining due to mitochondrial proliferation
![](../pics/biopsy/control/limb/nlsdhhp.jpg)
SDH stain
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Mitochondrial Disorders
COX + SDH
COX negative muscle fibers stain blue
![](../pics/biopsy/control/limb/coxsdhlp.jpg)
COX + SDH stain
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Lipid stain: Sudan Black
![](../pics/biopsy/control/limb/nlsudanlp.jpg)
Sudan Black stain
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Fiber types: Type 1 fibers stain darker than type 2
Myelin: In intramuscular nerves stains dark
![](../pics/biopsy/control/limb/nlsudanhp.jpg)
Sudan Black stain
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Glycogen stain: PAS
![](../pics/biopsy/control/limb/nlpasmp.jpg)
PAS stain
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Fiber types: Type 2 fibers stain darker than type 1
Capillary basal lamina: Stains dark
![](../pics/biopsy/control/limb/nlpashp.jpg)
PAS stain
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Normal Muscle: Transverse section
A band: Thick filaments surrounded by thin filaments
Scattered mitochondria between fibrils
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2/5/2021