Bones/Joints/Muscle 2

What is chondrodysplasia?

Abnormal endochondral ossification

What structure does chondrodysplasia affect?

Growth cartilage

Chondrodysplasia primarily affects which type of bone?

Long bones

Chondrodysplasia is also known as…

Disproportionate dwarfism

What are two chondrodysplastic breeds?

Daschund and Basset Hound

Failure of osteoclasts to resorb bone leads to which disorder?

Osteopetrosis

What is a common cause of osteopetrosis? Give one example.

In utero infections; bovine viral diarrhea virus (BVDV)

What genetic disorder results from failure of stable bone formation?

Osteogenesis imperfecta

What structures are not affected by osteogenesis imperfecta?

Growth plates

Metabolic bone diseases affect bone ______ and ______.

Strength; structure

What is one example of a metabolic bone disease?

Fibrous osteodystrophy

What is the end result of fibrous osteodystrophy?

Increased osteoclast activity; excessive bone resorption

Fibrous osteodystrophy leads to _______ bones.

Weak

What disease often leads to fibrous osteodystrophy in dogs?

Renal secondary hyperparathyroidism

What disease often leads to fibrous osteodystrophy in horses?

Nutritional secondary hyperparathyroidism

Which bone disease results from increased levels of parathyroid hormone?

Fibrous osteodystrophy

What is the function of PTH?

Mobilize calcium from bone

Renal secondary hyperparathyroidism results in increased PTH due to…

Decreased kidney function

Nutritional secondary hyperparathyroidism results in increased PTH due to…

Low dietary calcium and high dietary phosphorus

What is the term used to describe bone inflammation?

Osteomyelitis

Osteomyelitis often results from __________.

Bacterial/fungal infections

What are two methods for bacteria to enter the bone, causing osteomyelitis?

• Direct (trauma to bone)

• Hematogenous (bloodborne/embolic)

Bacteria from hematogenous osteomyelitis most often become trapped in which area of the bone?

Metaphysis

Hyperostotic diseases are caused by _____________ bone proliferation.

Non-neoplastic

Neoplastic diseases involved abnormal growth of…

Bone and/or cartilage

What kind of malignant bone cancer is caused when osteoblasts mutate?

Osteosarcoma

Osteoblasts produce primarily…

Osteoid

What type of malignant bone cancer usually affects flat bones?

Chondrosarcoma

What phrase is used to remember the locations of canine osteosarcoma?

Away from the elbows, toward the knees

What are “true joints”?

Synovial joints

Synovial joints unite two bone ends covered by…

Articular cartilage

The most important diseases in domestic animals affect…

Synovial joints

What is one route of bacterial entry in infectious arthritis?

Hematogenous (bloodborne)

When infectious arthritis bacteria enter hematogenously, they often affect ______ joints, causing __________.

Multiple; polyarthritis

What is the main feature of degenerative joint disease?

Gradual destruction of articular cartilage

What are two changes associated with degenerative joint disease?

Eburnation and osteophytes

What is eburnation?

Exposed subchondral bone becomes polished/smooth from continued use of joint

What is an osteophyte?

Irregular bony/cartilaginous nodule

Muscle atrophy leads to… (NOT a loss of fibers)

Decreased myofiber diameter

Muscle hypertrophy leads to…

Increased myofiber diameter (more myofilaments)

Muscle hyperplasia leads to…

Increased number of myofibers

What is the name of a congenital muscle hyperplasia disease? Which animals are often affected?

Double Muscling → Belgian White and Charolais cows, whippet dogs

What kind of muscle injury is caused by a single event (think: infectious)?

Monophasic

What kind of muscle injury is caused by repeated/ongoing trauma with concurrent regeneration (think: nutritional)?

Polyphasic

What is the common name for infectious myositis?

Blackleg

Which bacteria causes blackleg?

Clostridium chauvoei

Where do the bacteria that cause blackleg come from?

Spores/vegetative bacteria in feces of healthy animals

The bacterial spores that cause blackleg germinate, proliferate, and produce toxins when there is trauma to an area, causing a drop in oxygen tension known as…

Local hypoxia

Blackleg leads to __________ _________________ and ____________ myositis.

Acute necrohemorrhagic; emphysematous