Path 2 - Osteo 1

drraythe's version from 2016-05-03 00:28

GENERAL Bones/ Joints

Question Answer
What are the 8 possible responses of bones to injury?Atrophy
Disruption of endochondral ossification (cartilage turning to bone) affects what?Affects metaphyseal (growth plate) trabeculae (spongey bone, the little boney struts that compose this)
Bone can adapt to damage & abnormal use by...Changing its shape
W/ systemic dz & altered use, bone can change its...Mass
How is the structure of bone different if it is deposited slowly as opposed to rapidly?If deposited rapidly, it is woven (haphazard organization of collagen fibers & is mechanically weak)
If it's deposited slowly, it is lamellar (regular parallel alignment of collagen into sheets ("lamellae") & is mechanically strong)
If the periosteum is injured, how does it often respond?It will often form bone in response to injury (Periosteum is membrane that covers the outer surface of all bones)
(Review) Osteogenic cell is what & where does it live?Osteoblast, secretes osteoid/matrix. Once is it surrounded by the matrix is creates, it is in the lacunae & turns into an osteocyte w/ it's little processes
Immature bone is what structure & mature bone is what structure?Immature is woven
Mature is lamellar
(Review) What is the fxnal unit of cancellous/spongey bone? Compact/Cortical bone?Spongey = Trabeculae
Compact = Osteons (Haversion Systems) (swirly thing w/ haversion canal in middle & lacunae all around in swirls)
Flat bones do what kinda ossification?Intramembranous ossification
Cartilaginous models/long bones do what kinda ossification?Endochondral ossification
Joints → articular cartilage → what are the 4 responses this cartilage can have to injury?(1) Chondromalacia
(2) Fibrillation
(3) Erosion
(4) Eburnation
Chondromalacia is what?Softening/degenerating of cartilage
What is fibrillation of articular cartilage?Early degenerative change of articular cartilage, there is superficial erosion of cartilage (usually due to loss of proteoglycans, unmaskinig of collagen fibers, ↑ water content in chondrocytes)
What is eburnation of articular cartilage?Complete loss of articular cartilage (+ osteoclerosis of subchondral bone) (Burnination burns everything completely! Trogdor the Burninator leaves nothing behind!!)
Joints → Articular capsule/synovium/synovial fluid → what is the response of these structures of injury?Villous hypertrophy & hyperplasia (“velvety” appearance due to formation of synovial villi covered w/ hyperplastic synoviocytes)
What is the response of subchondral bone to injury?Sclerosis (hardening of tissue)

Abnormalities of Growth & Development

Question Answer
Osteopetrosis is a disorder of bone _________Resorption
Congenital Cortical Hyperostosis is a disorder of bone ___Modeling
Craniomandibular Osteopathy is a disorder of bone _________Modeling
Chondrodysplasias (chondrodystrophies) are disorders of...Endochondral ossification
Osteochondrosis Dissecans (OCD) is a disorder of..Endochondral ossification
Epiphysiolysis is a disorder of..Endochondral ossification
Cervical Vertebral Myelopathy is a disorder of...Endochondral ossification ((inclds (Cervical Vertebral Static Stenosis (CVS) & Cervical Vertebral Instability (CVI) )
Osteopetrosis is aka what kinda dysplasia? Another aka?Metaphyseal dysplasia, aka Marble Bone Dz
Who is Osteopetrosis inherited in?Autosomal recessive in Angus cattle (in birds it can be induced by Leukosis virus)
What is happening in Osteopetrosis?Failure of osteoCLASTS to resorb (remodel) the primary spongiosa, or 2° spongiosa (p.s. is the 1st bone that is formed, which is resorbed & then the 2° bone structures are formed)
Osteopetrosis is a failure of what cells?Osteoclasts
Osteopetrosis leads to osteo__SCLEROSIS
What's weird about the spongiosa (cancellous bone) in osteopetrosis?It extends into the medullary cavity! (hence you will see spicules in the cavity) eventually this crowds out the marrow czing Aplastic Anemia
What problem can occur bc of Osteopetrosis & why?APLASTIC ANEMIA, bc there is a bunch of bone in the medullary cavity crowding out the marrow
Gross lesions of Osteopetrosis?Bones are dense & thick (diffusely solid)
Small or no medullary cavity marrow spaces (it is filled w/ spicules of bone w/ central cores of calcified cartilage)
How do Osteopetrosis affected Angus calves appear?Stillborn
Brachygnathia inferior (shortened mandible)
Impacted molar teeth
Deformed cranial vaults which compress the brain
Pathological fractures
Are bones affected w/ Osteopetrosis easier or harder to break?EASIER TO FRACTURE bc lack tensile strength (think of a green vs a dry stick)
Congenital Cortical Hyperostosis aka? WHO gets this & how?Aka Diaphyseal Dysplasia. This is a autosomal recessive inherited disorder in pigs
What is happening in Congenital Cortical Hyperostosis?There is disorganization of the perichondrial ossification groove, leading to a chondrogenic membrane around the growth plate.....which means there is new periosteal bone formation on major long bones of the limbs & edema (in short, basically abnormal periosteal bone formation on long bones which ↑ the diameter of the bones)
How is the growth plate affected in Congenital Cortical Hyperostosis?↑ in diameter
What are the gross lesions of Congenital Cortical Hyperostosis?Piglets will have very thick, swollen, hard, rigid bones & are often stillbirths or early neonatal death bc of other defects (like starvation & cardiac insufficiency)
What problem can occur bc of Congenital Cortical Hyperostosis?Edema, bc swollen bone is blocking lymph flow
Craniomandibular Osteopathy (CMO) is aka, happens in WHO & WHY?Aka "Westie Jaw"; "Scottie Jaw"; "Lion Jaw". Happens in West Highland white or Scottish terrier dogs. It can be either idiopathic or autosomal recessive
What is happening in Craniomandibular Osteopathy (CMO)?New periosteal bone formation + irregular resorption = irregular thickening of bones
How does Craniomandibular Osteopathy (CMO) appear grossly?Bilaterally symmetrical thickening of the mandibular, occipital & temporal bones, tympanic bullae (often severely affected) & less often the limbs. There will be atrophy of associated musculature (painful condition)
What are Chondrodystrophies?1° lesions in growth cartilage
What are the 3 types/locations of 1° lesions in growth cartilage?Physis
Articular-Epiphyseal [AE] complex
Epiphyseal cartilage
Chondrodystrophies are ___ dwarfismDisproportionate dwarfism → short-legged w/ normal-sized heads
How do animals get Chondrodystrophies?(1) Idiopathic
(2) Inherited errors in genes that control chondrogenesis
What is the 1 type of chondrodystrophy in cattle he told us to focus on?Dexter (breed) "bulldog" calves
What is Osteochondrosis?Heterogenous group of lesions in growth cartilage of young animals → focal or multifocal failure (or delay) of endochondral ossification
(Not sure if important) Hallmark of the gross lesions of Osteochondrosis?Focal or multifocal retention of growth cartilage due to its failure to become mineralized & replaced by bone (failure of endochondral ossification)
(Not sure if important) Etiology of Osteochondrosis?Idiopathic
High incidence in species bred & fed to achieve maximal body weight at a young age
Cu deficiency induced by excess dietary Zn
There is a greater incidence of Osteochondrosis in dogs who...Growing dogs fed high calcium diets
(Not sure if important) What are the lesions of Osteochondrosis?Well demarcated wedge of white firm hyaline cartilage at the AE (articular-epiphyseal) complex or physis
Stages of resolution or 2°necrosis
Hemorrhage & mineralized debris in the adjacent bone
(Not sure how important) Common sites of osteochondrosis in various animals?Distal femur (esp. pigs)
Distal tibia & vertebral articular facets of horses
Proximal humerus of dogs
Proximal tibia of rapidly growing birds
What is Osteochondritis Dissecans (OCD)?When there are dysplasias at the AE complex (articular-epiphyseal)
Osteochondritis Dissecans (OCD) czs what to happen?Dysplasia of articular-epiphyseal complex → formation of clefts in the retained cartilage + fracture of the overlying articular cartilage → cartilaginous or osteochondral flap
If the flap czd by OCD is fractured off, what is it called & what does it do?Called a "joint mouse" which is now free in the joint space... this can interfere w/ mechanical movement of the joint
Sequelae of Osteochondrosis Dissecans?Degenerative Joint Dz
Ulceration & exposure of subchondral bone
What is Epiphysiolysis?Separation of epiphysis from the metaphysis bc of fissure formation horizontally through the physis
What is epiphysiolysis NOT associated w/?Not associated w/ focal or multifocal dysplasia (as in osteochondroses) (it's bc of fissure formation horizontally through the physis)
Lesions for Epiphysiolysis?Horizontal fissure/fracture through the physis + complete or partial separation of the epiphysis from the metaphysis
Cervical Vertebral Myelopathy (CVM) is czd by what?2° to static or dynamic compression on the spinal cord by abnormal cervical vertebrae which can cz this compression constantly due to absolute stenosis of the canal (static compression) or intermittently during movement [flexion] (dynamic compression)
Cervical Vertebral Myelopathy (CVM) is aka? What are the 2 types?Aka "Wobblers Syndrome"
(1) Static type (1-4 yr old horses, Older = Static/ set in their ways)
(2) Instability/laxity type (Babies are unstable!)
What is static type Cervical Vertebral Myelopathy (CVM) associated w/?Malformation of vertebrae, osteochondrosis (disturbance of endochondral ossification)
What is the instability/laxity type of Cervical Vertebral Myelopathy (CVM) associated w/?↑ mobility of cervical vertebral joint (associated w/ rapid growth)
2 specific examples of Cervical Vertebral Myelopathy (CVM) (& who is affected?)(1) Cervical Vertebral Stenotic Myelopathy (Horses)
(2) Cervical Spondylomyelopathies (Dogs)
Cervical Vertebral Stenotic Myelopathy happens in who? What are the problems/lesions associated w/ it?HORSES (horses are narrow-minded) & there will be:
Abnormal locomotion
Compression of spinal cord
Narrowing of vertebral canal
What are the 2 syndromes of Cervical Vertebral Stenotic Myelopathy (horses)?(1) Cervical static stenosis (1-4 yr old horses)
(2) Cervical vertebral instability (<1 yr old horses)
Cervical Vertebral Myelopathy (CVM) → Cervical Static Stenosis happens in who? What czs it? Where is the affecetd area?OLDER horses, 1-4 years (older horses are more set (static) in their ways)
Narrowing @ C5-C7
Usually due to:
Vertebral malformation
Articular subluxation
Cervical Vertebral Myelopathy (CVM) → Cervical Static Stenosis → lesions?Hypertrophy of ligamentum flavum
Dorsal narrowing of vertebral canal @ C5-C7 (involves the less mobile verts)
Compressive myelomalacia
Fibrillation (upper layers sloughing)
Eburnation (loss of articular cartilage)
Osteophytes (bone spurs)
Cervical Vertebral Myelopathy (CVM) → Cervical Vertebral Instability → happen in who? What czs this?Happens in YOUNG horses (young = more unstable in general) & is usually due to rapid growth, genetic
Instability @ C3-C5
Cervical Vertebral Myelopathy (CVM) → Cervical Vertebral Instability → lesions?Fibrillation (upper layers sloughing)
Eburnation (loss of articular cartilage)
Osteophytes (bone spurs)
Narrowed vertebral canal → compression of spinal cord
Cervical Vertebral Stenotic Myelopathy (instability or stenosis) BOTH lead to WHAT?Spinal cord compression