Musculoskeletal Pathology I Flashcards
What is the skeleton?
- Bones, Joints and their supporting ligaments
- responsible for supporting the body and enabling movement
What are the two major factors that regulate deposition and resorption of bone?
- Mechanical forces
- Hormonal agents e.g- calcitriol, PTH, oestrogen, (modulated resorption via osteoclasts
How does bone modelling occur?
bones are shaped or reshaped via the independent action of osteoblasts and osteoclasts
How does bone remodelling occur?
osteoblasts and osteoclasts work sequentially in the same bone remodelling unit
* the adult skeleton is renewed throughout life
* most prominent on cancellous bone surfaces
What does disruption of endochondral ossification affect?
metaphyseal trabeculae (decreased rate of elongation)
* the bone changes its shape to adapt to damage and abnormal use
* the newly formed bone is woven not lamellar (it’s weaker)
How does bone fracture occur?
Forces exceed a bones ability to compensate (either too fast or too strong)
What is achondroplasia?
absence of cartilage development
What is chondrodysplasia?
disorder of cartilage development
What is skeletal dysplasia?
disorder of skeletal development
What is brachycephaly?
shortening of the head
What is brachygnathia?
shortening of the jaw
What is palatoschisis?
Cleft Palate
What is prognathia?
abnormal projection of the jaw
What is Pectus excavatum?
concavity of the sternum
What is Kyphosis?
abnormal dorsal curvature of spinal column
What is Lordosis?
abnormal ventral curvature of the spinal column
What is scoliosis?
lateral deviation of spinal column
What is block vertebrae?
failure of two vertebral bodies to separate
What is hemivertebrae?
failure of two halves of vertebral body to fuse
What is spina bifida?
failure of dorsal midline closure
What is amelia?
absence of one or more limbs
What is Hemimelia?
absence of the distal part of the limb
What is Micromelia?
presence of abnormally small limbs
What is notomelia?
accesory limb attached to the back
What is peromelia?
congenital deformity of the limbs
What is phocomelia?
absence of the proximal portion of one or more limbs
What is Adactyly?
absence of a digit
What is Dactylomegaly?
abnormally large digits
What is Ectrodactyly?
partial or complete absence of a digit
What is Polydactyly?
presence of supernumerary digits
What is polypodia?
presence of supernumerary feet
What is syndactyly?
fusion of digits
What is osteogenesis imperfecta?
Group of connective tissue disorders characterised by
1. Bone fractures due to osteopenia (decrease in bone density)
2. Joint laxity
3. Blue sclerae (reduced thickness)
What causes osteogenesis imperfecta?
Mutation in COL1A1 and COL1A2 genes, the severity is on a spectrum depending on what alleles are inherited
What is osteopetrosis?
disorder of bone resorption, characterised by increased bone density
* failure of resorption by osteoclasts
What are the two causes of osteopetrosis?
- Inherited - mutation that impairs osteoclats formation
- Infectious- in-utero BVD or FeLV infection
What is congenital cortical hyperostosis?
- disorder of bone remodelling
- autosomal recessive disease of newborn pigs
- abnormal radial periosteal bone formation
What is craniomandibular osteopathy?
disorder of bone modelling, mainly affects WHWT and Scottish Terriors
When does craniomandibular osteopathy become apparant?
4-7 months then regresses
What is chondrodysplasia?
disorder of endochrondral ossification
What does chondrodysplasia result in?
disproportionate dwarfism
What mutation does FGFR3 cause?
spider lamb chondrodysplasia
What breeds does FGFR4 effeect?
causes chondrogenesis
Dachshund, Pekinese, Basset Hound
What does osteochrondrosis latens look like histologically?
Well demarcated area of necrosis in cartilage
What is osteochondrosis dissecans?
traumatic clefting through the area of necrosis
* fragments of cartilage break off
* can resolve without clefting
What is cervical vertebral myelopathy?
‘wobbler syndrome’ disorder of endochondral ossification
What does cervical vertebral myelopathy cause?
- Neurological disease secondary to compression of the spinal cord and therefore causes abnormally developed cervical vertebrae
What species are most affected by wobbler syndrome?
Horses and large breed dogs
What is osteoporosis?
reduced bone mass, porous, thin and fragile
What are the causes of osteoporosis
- Protein calorie malnutrition
- immobilisation
- glucocorticoid excess
- oestrogen or androgen deficiency
- advanced age
What is Ricketts?
Failure of bone mineralisation with subsequent deformities and fractures in the growing skeleton
What causes Ricketts?
Vitamin D deficiency and phosphorus deficiency
What is fibrous osteodystrophy?
decreased bone mass, increased pliability due to replacement by fibro-osseous tissue
What causes fibrous osteodystrophy?
decreased bone mass, increased pliabilty due to replacement by fibro-osseous tissue
What causes fibrous osteodystrophy?
Hyperparathyroidism
What is an osteophyte?
nodular, benign growth at the margins of a synovial joint
What is an Enthesophyte?
ossification of a tendon or ligament
What is a Hyperostosis?
diameter of the bone has increased
What is an osteochondroma?
multiple cartilaginous exostoses
What are bone cysts
appear radiographically as well demarcated
What occurs when the metaphyseal trabeculae is affected?
Decreased rate of elongation of the bone
What is Hypertrophic osteopathy?
Progressive, often bilateral, periosteal new-born formation in diaphysis and metaphysis
What is static stenosis?
Constant compression due to anatomic stenosis of the spinal cord
also called cervical vertebral static stenosis
What is dynamic stenosis?
compression only during movement/ flexion
also called cervical vertebral instability
What type of stenosis affects dogs?
Static
What is characteristic about a lead toxin lesion?
Characteristic line parallel to the growth plate
What is an exostosis?
nodular bony growth projecting from a bones surface
What is an ensotosis?
Bony growth from within the medullary cavity
What is hypertrophic osteopathy called in humans?
Maries Disease
What does aneurysmal mean?
Filled with blood or serosanguinous fluid (not lined by endothelium)
