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Created page with "*Firstly segmental necrosis *-> death of satellite cells **Causes regeneration but myoblast precursors hav..."
*Firstly [[Muscles Degenerative - Pathology#Necrosis|segmental necrosis]]
*-> death of satellite cells
**Causes [[Muscle Regeneration|regeneration]] but myoblast precursors have to be recruited from viable fibres
*-> death of all cells
*Mostly healed by fibrosis and scar formation
*May attempt regeneration by [[Muscle Regeneration|budding]]
Main causes:
*'''Vascular occlusion'''
**Infarction from embolism is rare due to collateral circulation
**Extension of infarcts depends on size of vessels occluded
***Small capillaries -> segmental [[Muscles Degenerative - Pathology#Necrosis|necrosis]]
***Large arteries -> whole muscle areas, including sattelite cells, are killed
**Healed by fibrosis
**May be due to:
***Blockage of iliac arteries by aortic-iliac thrombosis in horses
***Blockage of aortic bifurcation in cats
***[[Dirofilaria immitis|''Dirofilaria immitis'']] arteritis in dogs
***Vasculitis due to [[Reoviridae#Bluetongue Virus|bluetongue virus]] in sheep
***[[Haemorrhage#Purpura haemorrhagica|'''Equine purpura haemorrhagica''']]
****Non-contagious, sporadic
****Grossly:
*****Subcutaneous oedema
*****Scattered haemorrhagic foci throughout skin and muscles
*****Vasculitis -> infarcts of muscles
****May cause myoglobinuria if extensive
****Possibly immune mediated
****In horses post [[:Category:Streptococcus species|streptococal]] infection, especially [[Respiratory Bacterial Infections - Pathology#Strangles|strangles]]
*'''External pressure'''
**During prolonged recumbency, e.g. anaesthesia, inability to rise, or due to too tightly fitting bandages or casts
**Post anaesthesia myopathy especially in horses
***Dorsal recumbancy -> gluteals and longissimus ischaemia
***Lateral recumbancy -> triceps brachii, pectoralis, deltoideus and brachiocephalicus ischaemia
**Caused by pressure on muscle > perfusion pressure of capillaries
**Downer cows - vetral recumbency -> ischaemia of pectoral muscles and muscles of limbs tucked under the animal
**Pregnant ewes with twins or triplets -> internal abdominal oblique muscle ischaemic necrosis -> potential rupture
*'''Muscle swelling''' where it cannot expand
**E.g. supracoracoid muscle infarction in some breeds of turkeys after flapping their wings
***Surrounded by inelastic fascial sheath and bone
[[Category:Muscles - Degenerative Pathology]]
*-> death of satellite cells
**Causes [[Muscle Regeneration|regeneration]] but myoblast precursors have to be recruited from viable fibres
*-> death of all cells
*Mostly healed by fibrosis and scar formation
*May attempt regeneration by [[Muscle Regeneration|budding]]
Main causes:
*'''Vascular occlusion'''
**Infarction from embolism is rare due to collateral circulation
**Extension of infarcts depends on size of vessels occluded
***Small capillaries -> segmental [[Muscles Degenerative - Pathology#Necrosis|necrosis]]
***Large arteries -> whole muscle areas, including sattelite cells, are killed
**Healed by fibrosis
**May be due to:
***Blockage of iliac arteries by aortic-iliac thrombosis in horses
***Blockage of aortic bifurcation in cats
***[[Dirofilaria immitis|''Dirofilaria immitis'']] arteritis in dogs
***Vasculitis due to [[Reoviridae#Bluetongue Virus|bluetongue virus]] in sheep
***[[Haemorrhage#Purpura haemorrhagica|'''Equine purpura haemorrhagica''']]
****Non-contagious, sporadic
****Grossly:
*****Subcutaneous oedema
*****Scattered haemorrhagic foci throughout skin and muscles
*****Vasculitis -> infarcts of muscles
****May cause myoglobinuria if extensive
****Possibly immune mediated
****In horses post [[:Category:Streptococcus species|streptococal]] infection, especially [[Respiratory Bacterial Infections - Pathology#Strangles|strangles]]
*'''External pressure'''
**During prolonged recumbency, e.g. anaesthesia, inability to rise, or due to too tightly fitting bandages or casts
**Post anaesthesia myopathy especially in horses
***Dorsal recumbancy -> gluteals and longissimus ischaemia
***Lateral recumbancy -> triceps brachii, pectoralis, deltoideus and brachiocephalicus ischaemia
**Caused by pressure on muscle > perfusion pressure of capillaries
**Downer cows - vetral recumbency -> ischaemia of pectoral muscles and muscles of limbs tucked under the animal
**Pregnant ewes with twins or triplets -> internal abdominal oblique muscle ischaemic necrosis -> potential rupture
*'''Muscle swelling''' where it cannot expand
**E.g. supracoracoid muscle infarction in some breeds of turkeys after flapping their wings
***Surrounded by inelastic fascial sheath and bone
[[Category:Muscles - Degenerative Pathology]]