Unit 1- Bone Flashcards
Chondrodysplasia
Premature growth plate closure due to rapid endochondral ossification causes deformity
Dexter Bulldogs
Dexter cattle susceptible to congenital lethal chondrodysplasia
Micomelia
Shortening of the limbs
Micromelic Achondodysplasia
Short legs
Brachiocephalic Achondrodysplasia
Short snout
Cervico-Vertebral Stenotic Myelopathy
Abnormal cervical vertebrae cause stenosis of the spinal canal
Dynamic Cervical Stenotic Myelopathy
Clinical signs more prominent if neck is flexed
Static Cervical Stenotic Myelopathy
Clinical signs always severe
Osteopetrosis
Osteoclast failure to reabsorb primary spongiosa, causes susceptibility to fracture and aplastic anemia due to lack of medullary spaces
Congenital Cortical Hyperostosis of Pigs
Forelimbs appear swollen due to deposition of bone outside periosteum
Amelia
Absence of a limb
Hemimelia
Absence of the distal half of a limb
Polymelia
Extra limbs
Phocomelia
Shortening of the long bones and seal limbs
Syndactyly
Digit fusion
Polydactyly
Extra digits
Lordosis
Ventral deviation of the vertebral column
Kyphosis
Dorsal deviation of the vertebral column
Scoliosis
Lateral deviation of the vertebral column
Kyphoscoliosis
Dorso-lateral deviation of the vertebral column
Hemivertebra
Triangular malformed vertebra causing localized malformations of the vertebral column
Swayback
Acquired lordosis in horses due to degenerative joint disease
Angular Limb Deformities
Twisting of the bone, common in young animals and horses
Angular Limb Deformity Causes
Malposition in utero, joint laxity, hypothyroidism, trauma, malnutrition, impaired endochondral ossification
Varus Limb Deformity
Inward deviation, bow legged
Valgus Limb Deformity
Outward deviation, knock kneed
Osteodystrophies
Metabolic bone diseases, failure of production, maintenance, or mineralization of bone matrix
Osteodystrophy Causes
Disturbed bone growth, modeling, or remodeling due to nutritional or hormonal imbalance
Nutritional Metabolic Bone Disease
Deficiency in vitamin C, D, Ca, P, or protein
Hormonal Metabolic Bone Disease
PTH causes increased Ca resorption, estrogens, and corticosteroids cause osteoporosis
Disuse Metabolic Bone Disease
Physical inactivity
Toxic Metabolic Bone Disease
Lead and fluoride poisoning, hypervitaminosis A
Domestic animal cause of MBD
Most often by nutritional deficiency of more than one nutrient
Osteoporosis
Decreased amount of bone but bone remains normal, susceptible to fracture
Nutritional Osteoporosis
Starvation most common in animals, Cu deficiency, vitamin C deficiency
Aging Osteoporosis
Resorption outpaced bone formation with age
Serous Atrophy
Fat becomes gelatinous and translucent
Rickets
Defective calcification of osteoid and abnormal mineralization of cartilage matrix affecting young animals
Rickets Cause
Usually vitamin D or phosphorus deficiency
Rickets Lesions
Irregular growth plate thickening, enlarged ends of long bones, enlarged costochondral junctions, bowed long bones, hemorrhage beneath cartilage, fracture, ribs bend at necropsy
Rachitic Rosary
Enlargement of costochondral joints
Osteodystrophic lines
Growth arrest lines indicate periods of malnutrition
Osteomalacia
Failure in mineralization of osteoid due to vitamin D or P deficiency occurring in adult animals with closed growth plates
Fibrous Osteodystrophy
Extensive bone resorption and replacement by fibrous connective tissue and poorly mineralized immature bone due to hyperparathyroidism
Common animals with fibrous osteodystrophy
Horses, pigs, dogs, cats, reptiles, and new world monkeys
Primary Hyperparathyroidism and Fibrous Osteodystrophy
Parathyroid adenomas in dogs causes excess PTH and hypercalcemia and hypophosphatemia, causes thyroid C cell hyperplasia, hypercalcemic nephropathy, and metastatic soft tissue mineralization
Hypercalcemic Nephropathy
Deposition of calcium in kidneys
Renal Secondary Hyperparathyroidism and Fibrous Osteodystrophy
Deficiency of Ca or vitamin D or excess P affects young animals and causes replacement of bone by fibrous connective tissue
Bran Disease
Big head in horses, nutritional secondary hyperparathyroidism causes fibrous osteodystrophy
Renal Secondary Hyperparathyroidism and Fibrous Osteodystrophy
P retention due to loss of glomerular function and inadequate calcitriol synthesis occurring commonly in dogs
Rubber Jaw
Renal osteodystrophy in dogs causes bones of the head to become swollen and firm rather than hard, teeth are mobile and malpositioned, gums are swollen
Lead Poisoning
Lead interferes with osteoclast activity and forms lead line of increased bone density in metaphysis
Metaphysis
Growth Plate
Hypervitaminosis A
Causes deforming or ankylosing cervical spondylosis in cats that consume bovine livers
Deforming Cervical Spondylosis
Formation of osteophytes on cervical vertebrae causes lameness and neurological signs
Ankylosis
Fixation of a joint
Osteophytes
Nodules of bone on the periosteal surface
Necrosis
Death of osteocytes due to ischemic injury
Sequestrum
A piece of necrotic bone isolated from the remaining viable vone
Involucrum
Area of granulation tissue around the sequestrum
Traumatic Fracture
Broken by excessive force
Pathologic Fracture
Abnormal bone broken by minimal trauma or normal weight bearing
Closed Fracture
Simple; soft tissue around the bone is still intact
Open Fracture
Compound; bone ruptures the soft tissue
Comminuted Fracture
Bone breaks into several small fragments
Avulsed Fracture
Caused by the pull of a ligament or tendon at its insertion
Microfracture/Infraction
Fracturing of trabeculae without external cortical deformation
Sequel to pig tail biting
Infection travels to vertebrae and causes an abscess that may rupture and result in pathologic fracture and compression of the spinal cord
Osteosarcoma
Common in dogs
Fracture Repair
Hematoma forms, mesh facilitates fibroblast accumulation and blood vessel formation, inflammatory cells absorb necrotic debris and stimulate osteoprogenitor cells, callus forms and then bone heals
Age and Bone Healing
Healing capacity decreases with age
Rib Fracture Healing
It is challenging to stabilize the ribs so callus will be replaced by bone and may still be thickened
Fracture Complications
Bone necrosis and sequestrum formation, pseudoarthritis formation, osteomyelitis from compound fractures, cachexia if unable to feed
Pseudoarthritis
Formation of a false joint
Osteomyelitis
Inflammation in the bone. common in young animals
Aseptic Inflammation
Trauma can cause osteoperositis with formation of osteophytes
Source of Osteomyelitis
Omphalophlebitis in neonates
Omphalophlebitis
Umbilical vein infection
Osteomyelitis Localization
The vertebral bodies in piglets or the metaphyses of long bones
Long Bone Vessels
Small vessels loop as they approach the metaphysis and can trap infection, inflammation can spread and cause osteomyelitis
Draining Sinus
Tracks of drainage can extend into the joints or skin
Cause of necrosis in foals
Salmonella
Gram positive filamentous bacteria in sulfur granules causing characteristic bone maceration
Actinomyces bovis
Hypertrophic Pulmonary Osteoarthropathy
Maries disease, periosteal bone proliferation in the long bones caused by a space occupying lesion in the thoracic cavity
Causes of Maries Disease
Space occupying lesions in the thoracic cavity, rhabdomyosarcomas of the urinary bladder in dogs, and ovarian tumors in mares
Canine Craniomandibular Osteopathy
Lion Jaw, proliferation of osteophytes on the bones of the head and mandible
Lion Jaw Breed
West Highland White Terriers
Common Tumors
Primary tumors
Dog Tumors
Malignant
Horse and Cattle Tumors
Benign Tumors
Osteoma Species
Large animal
Osteosarcoma Species
Dogs
Osteosarcoma
Common in large breed male dogs, close to the knee and away from the elbow
Osteosarcoma Metastasis Site
Lungs
Chondrosarcoma
Flat bones affected, rare in species besides dogs, malignant