Limb

Limb Muscles: Control

Acid phosphatase
Alkaline phosphatase
ATPase
Capillaries
Congo red
Cytochrome oxidase
Esterase
Gomori trichrome

Hematoxylin & Eosin (H&E)
NADH
PAS
Succinate dehydrogenase
Sudan
VvG
Vessels, Large
Perimysium
Sizes

H&E stain

Fiber size: Mild variation
Myonuclei: Dark-stained; Normally present at periphery of muscle fibers
Endomysial connective tissue: Normal
Capillaries, Endomysial: Small, Between muscle fibers

H&E stain

Congo red stain

Gomori trichrome stain

2 fiber types: Type 1 muscle fibers have darker, more punctate cytoplasm
Connective tissue: Stains Green
Lipid membranes: Stain red

Gomori trichrome stain

VvG stain

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

VvG stain

Internal architecture

NADH stain

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

NADH stain

Fiber Types

ATPase
pH 9.4
pH 4.6
pH 4.3
Ultrastructure
Myosin HC types
Type grouping

ATPase pH 9.4

ATPase pH 9.4 stain

Type 1 fibers: Intermediate color
Type 2 fibers: Dark color

ATPase pH 4.6

ATPase pH 4.6 stain

Type 1 fibers: Dark color
Type 2A fibers: Pale
Type 2B fibers: Intermediate color

ATPase pH 4.6 stain

ATPase pH 4.3

ATPase pH 4.3 stain

Type 1 fibers: Dark color
Type 2A fibers: Pale
Type 2C fibers (Immature; Abnormal) (Below): Intermediate color

ATPase pH 4.3 stain

ATPase may also stain endomysial capillaries

ATPase pH 4.3 stain

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

Alkaline phosphatase stain

Endomysial vessels
Some penetrating vessels, more in a few areas than others, stain for alkaline phosphatase
Small endomysial capillaries do not normally show staining

Alkaline phosphatase stain

Acid phosphatase stain
Red, subsarcolemmal staining of regions with lipofuscin: More with increasing age

Acid phosphatase stain

Esterase stain

Esterase stain

Neuromuscular junctions: Dark red regions on muscle fiber surface, normally contain 1 or 2 segments

Esterase stain

Mitochondrial Stains

Cytochrome Oxidase (COX)

COX stain

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

COX stain

Succinate Dehydrogenase (SDH)

SDH stain

Fiber types
Type 1: Dark
Type 2: Intermediate or Pale
Staining pattern: Reticular & Punctate
Mitochondrial disease: Dark staining due to mitochondrial proliferation