Neuromuscular

Extraocular Muscles


Muscle patterns


H&E stain
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
Perimysial Vessels: Normal structure
Intramuscular nerves: May be abundant

VvG stain

Muscle fibers: Sizes & Regional patterns


H&E stain
Internal architecture
  Varied: Among, & within, fascicles
  May be smaller at surface of muscle (Above)

H&E stain

NADH stain

Muscle fibers: Morphology

Muscle fibers
  Size: Varied; 10 to 50 μM in diameter

H&E stain

H&E stain
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

H&E stain

H&E stain


Congo red stain
Muscle fibers
  Internal architecture: Irregular
  Myonuclei: Large

Congo red stain
Neuromuscular junctions: Have appearance of sarcoplasmic pads

Congo red stain


VvG stain
Internal architecture: Variable in different regions; Coarse

VvG stain
Neuromuscular junctions: Dark-stained cytoplasm around surface of muscle fibers

VvG stain
Neuromuscular junctions: Dark-stained cytoplasm on surface of muscle fibers

VvG stain


Gomori trichrome stain
Mitochondria
  Abundant in muscle fibers
  Some muscle fibers appear "ragged red"

Gomori trichrome stain
Some muscle fibers appear "ragged red"

Gomori trichrome stain

Internal architecture


NADH stain
Internal architecture: Coarse or Punctate patterns

NADH stain
Internal architecture
  Some muscle fibers are very darkly stained
  Sarcoplasmic reticulum staining: Coarse; Punctate

NADH stain

EOM: Mitochondria


SDH stain
Mitochondria are more abundant than in limb muscles
  Some muscle fibers are very dark stained for SDH

SDH stain

SDH stain


COX stain
Mitochondria are more abundant than in limb muscles
  Some muscle fibers are very dark stained for COX
  Mitochondria appear large

COX stain

EOM: Fiber types


ATPase pH 9.4 stain
Fiber types
    ATPase pH 9.4: Dark stained


ATPase pH 4.3 stain
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

ATPase pH 4.3 stain

ATPase pH 4.6 stain

EOM: Neuromuscular junctions


Esterase stain
Neuromuscular junctions
  Dark stained by esterase
  Large
  May extend around surface of muscle fibers

Esterase stain
Neuromuscular junctions
  Varied sizes
  May have 2 patches on single muscle fiber

Esterase stain


Acid phosphatase stain

Acid phosphatase positive granules in muscle fibers


Acid phosphatase stain

EOM: Endomysial capillaries


Alkaline phosphatase stain
Alkaline phosphatase stain: Increased compared to limb muscles

EOM: Lipid in muscle fibers

Muscle fibers have scattered, small, lipid droplets

Sudan black stain

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7/12/2016