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[[Image:Lumpyjaw1.gif|right|thumb|125px|<small><center>Lesion caused by Actinomyces Bovis(Courtesy of Alun Williams (RVC))</center></small>]]
*"Lumpy jaw"
====Clinical====

*Seen mainly in cattle and exotics caused by ''[[Actinomyces bovis]]'' producing [[Bones Inflammatory - Pathology#Osteomyelitis|osteomyelitis]] of mandible.
*Mostly young animals.
*Will not heal without treatment and jaw enlarges until animal cannot eat.

====Pathogenesis====

*Starts as alveolar periostitis of lower cheek [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology|teeth]], due to ingestion of poor coarse roughage e.g. straw or hay with lots of thistles.
*Slowly enlarging [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] (occasionally [[Skull and Facial Muscles - Anatomy & Physiology#Maxilla|maxilla]]) due to granulomatous inflammation producing much fibrous tissue.
*No real pus formation but "'''sulphur granules'''" in middle of lesion.
*Organism causes "'''pyogenic granuloma'''."

*Can grow to enormous size (e.g. size of grapefruit) and whole of mandible is blown apart by multiple foci of infection.

<small>Also see:[[Tongue - Pathology#Actinobacillosis|Actinobacillosis - "Wooden Tongue" (Courtesy of Alun Williams (RVC))</small>]]

====Pathology====

3 major features:

#Inflammatory removal of bone. As cortex of bone is pushed out by central inflammation produces thinning of bone cortex with proliferation of new periosteal bone. The centre of the [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] is eroded forming a honeycomb-like bone. Eventually will erode through bone producing [[Granuloma|granulomatous]] lesion on bottom of [[Skull and Facial Muscles - Anatomy & Physiology#Mandible (mandibula)|mandible]] and eventually eroding through skin.
#Granuloma with micro abscess's in centre with greenish / yellow granules in middle of pus. These granules known as "sulphur bodies". Sulphur body is a colony of tangled mass of Actinomyces filaments. This is surrounded by [[Neutrophils - WikiBlood|neutrophils]] and [[Macrophages - WikiBlood|macrophages]] forming a pyogenic granuloma.
#Masses of fibrous tissue surround the granuloma and fill the spaces where bone has been destroyed.
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