Extraocular Muscles
Muscle patterns: Normal Adult EOM
![](../pics/biopsy/muscle/eom/eomhevlp.jpg)
H&E stain
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Muscle Fiber size variation: Mild to moderate
Fascicles: Smaller than
limb or
trunk muscles
Endomysial connective tissue
More between muscle fibers than
limb or
trunk muscles
Especially in regions with intramuscular nerves
Perimysial Vessels: Normal structure
Intramuscular nerves: May be abundant
![](../pics/biopsy/muscle/eom/eomvvgvlp.jpg)
VvG stain
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Muscle fibers: Sizes & Regional patterns
![](../pics/biopsy/muscle/eom/eomhemp.jpg)
H&E stain
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Internal architecture
Varied: Among, & within, fascicles
May be smaller at surface of muscle (Above)
![](../pics/biopsy/muscle/eom/eomreghe.jpg)
H&E stain
|
![](../pics/biopsy/muscle/eom/eomregnadh.jpg)
NADH stain
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Muscle fibers: Morphology
Muscle fibers
Size: Varied; 10 to 50 μM in diameter
![](../pics/biopsy/muscle/eom/eomhehp6.jpg)
H&E stain
|
![](../pics/biopsy/muscle/eom/eomhehp3.jpg)
H&E stain
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Muscle fibers
Size: Varied; 10 to 50 μM in diameter
Myonuclei: Large or Small
Neuromuscular junctions: Pale regions around muscle fibers (Arrow)
Motor point: Endomysial connective tissue increased
![](../pics/biopsy/muscle/eom/eomhehp1.jpg)
H&E stain
|
![](../pics/biopsy/muscle/eom/eomhehp2.jpg)
H&E stain
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![](../pics/biopsy/muscle/eom/eomcrhp1.jpg)
Congo red stain
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Muscle fibers
Internal architecture: Irregular
Myonuclei: Large
![](../pics/biopsy/muscle/eom/eomcrhp2.jpg)
Congo red stain
|
Neuromuscular junctions: Have appearance of sarcoplasmic pads
![](../pics/biopsy/muscle/eom/eomcrhp3.jpg)
Congo red stain
|
![](../pics/biopsy/muscle/eom/eomvvghp6.jpg)
VvG stain
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Internal architecture: Variable in different regions; Coarse
![](../pics/biopsy/muscle/eom/eomvvghp5.jpg)
VvG stain
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Neuromuscular junctions: Dark-stained cytoplasm around surface of muscle fibers
![](../pics/biopsy/muscle/eom/eomvvghp2.jpg)
VvG stain
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Neuromuscular junctions: Dark-stained cytoplasm on surface of muscle fibers
![](../pics/biopsy/muscle/eom/eomvvghp3.jpg)
VvG stain
|
![](../pics/biopsy/muscle/eom/eomgthp2.jpg)
Gomori trichrome stain
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Mitochondria
Abundant in muscle fibers
Some muscle fibers appear "ragged red"
![](../pics/biopsy/muscle/eom/eomgthp3.jpg)
Gomori trichrome stain
|
Some muscle fibers appear "ragged red"
![](../pics/biopsy/muscle/eom/eomgthp1.jpg)
Gomori trichrome stain
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Internal architecture
![](../pics/biopsy/muscle/eom/eomnadhhp.jpg)
NADH stain
|
Internal architecture: Coarse or Punctate patterns
![](../pics/biopsy/muscle/eom/eomnadhhp1.jpg)
NADH stain
|
Internal architecture
Some muscle fibers are very darkly stained
Sarcoplasmic reticulum staining: Coarse; Punctate
![](../pics/biopsy/muscle/eom/eomnadhhp2.jpg)
NADH stain
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EOM: Mitochondria
![](../pics/biopsy/muscle/eom/eomsdhlp.jpg)
SDH stain
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Mitochondria are more abundant than in limb muscles
Some muscle fibers are very dark stained for SDH
![](../pics/biopsy/muscle/eom/eomsdhhp1.jpg)
SDH stain
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![](../pics/biopsy/muscle/eom/eomsdhhp2.jpg)
SDH stain
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![](../pics/biopsy/muscle/eom/eomcoxlp.jpg)
COX stain
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Mitochondria are more abundant than in limb muscles
Some muscle fibers are very dark stained for COX
Mitochondria appear large
![](../pics/biopsy/muscle/eom/eomcoxhp.jpg)
COX stain
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EOM: Fiber types
![](../pics/biopsy/muscle/eom/eomatp94mp.jpg)
ATPase pH 9.4 stain
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Fiber types
ATPase pH 9.4: Dark stained
![](../pics/biopsy/muscle/eom/eomatp43lp2.jpg)
ATPase pH 4.3 stain
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Fiber types
Most similar to type 2C
ATPase pH 4.6 & 4.3: Intermediate stained
Few fibers similar to type I
ATPase pH 4.6 & 4.3: Dark stained
![](../pics/biopsy/muscle/eom/eomatp43mp.jpg)
ATPase pH 4.3 stain
|
![](../pics/biopsy/muscle/eom/eomatp46mp.jpg)
ATPase pH 4.6 stain
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EOM: Neuromuscular Junctions
![](../pics/biopsy/muscle/eom/eomesthp3.jpg)
Esterase stain
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Neuromuscular Junctions
Dark stained by esterase
Large
May extend around surface of muscle fibers
![](../pics/biopsy/muscle/eom/eomesthp2.jpg)
Esterase stain
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Neuromuscular Junctions
Varied sizes
Usually have 1 or 2 patches on single muscle fiber
![](../pics/biopsy/muscle/eom/eomesthp1.jpg)
Esterase stain
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![](../pics/biopsy/muscle/eom/eomacpmp.jpg)
Acid phosphatase stain
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Acid phosphatase positive granules in muscle fibers
![](../pics/biopsy/muscle/eom/eomacphp.jpg)
Acid phosphatase stain
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EOM: Endomysial capillaries
![](../pics/biopsy/muscle/eom/eomalp.jpg)
Alkaline phosphatase stain
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Alkaline phosphatase stain: Increased compared to limb muscles
EOM: Lipid in muscle fibers
Muscle fibers have scattered, small, lipid droplets
![](../pics/biopsy/muscle/eom/eomsudan.jpg)
Sudan black stain
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7/12/2016