skeletal m and tendon photos

perimyseum

epimyseum

endomysium

A) epitenon (CT)

B) tertiary fibre bundle

C) 2° fibre bundle (fascicle)

D) endotenon (CT)

E) 1° collagen fibre bundle (subfascicle)

F) collagen fibre

G) collagen fibril

monophasic injury

polyphasic injury

myolysis - muscle necrosis

muscle necrosis > fibrosis!

hypertrophy

atrophy

degeneration eg fat infiltration

ischaemic necrosis (from downer cow syndrome)

nutritional myopathy eg white muscle disease

toxic myopathies (characterized by white muscle as well)

exertional myopathies

myoglobinuric nephropathy (from equine exertional rhabdomyolysis)

clostridial (necrohaemorrhagic) myositides - “gas gangrene” and “malignant oedema” (horses), “blackleg” (cattle)

pyogenic/suppurative myositides; Trueperella pyogenes (cattle, sheep), Corynebacterium pseudotuberculosis (horse, sheep goat), Pasteurella multocida (male intact cats)

fibrosing and granulomatous myositis;

Actinobacillus lignieresii “wooden tongue” (cattle), Actinomyces bovis “lumpy jaw” (cattle), Staphylococcus aureus “botryomycosis” (horses, pig, mice)

polymyositosis

arthrogryposis

feline (Duchenne’s type) muscular dystrophy

malignant hyperthermia “porcine stress syndrome”, “pale soft exudative pork”

hyperkalemic periodic paralysis (HYPP) > well-defined muscles

denervation (neurogenic) atrophy

rhabdomyoma (benign in heart) - 1° neoplasia

rhabdosarcoma (malignant) - 1° neoplasia