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

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 pH 4.3 stain

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