Bone (Ex3) Flashcards
(38 cards)
1
Q
What is woven bone?
A
- immature bone present during fetal development, and in the early stages of bone repair
- collagen fibers randomly arranged, have a criss-cross pattern microscopically
2
Q
What is lamellar bone?
A
- mature bone
- collagen fibers are arranged in a parallel pattern
3
Q
Intramembranous ossification
A
- occurs within membranes of condensed primitive mesenchymal tissue
- flat bones of the skull
4
Q
Endochondral ossification
A
- occurs in majority of bones of the skeleton
- bone develops from cartilaginous model, that is replaced by osseous tissue present in ossification centers
- in ossification centers of mature bone, and growth plates of developing bone
5
Q
Describe chondrodysplasia
A
- membranous apositional growth is normal, but intersititial growth of cartilage is abnormal
- results in premature close of growth plates and decreased length of long bones
- breed associated, usually hereditary
6
Q
What is “Dexter Bulldog”?
A
- congenital lethal chondrodysplasia
- common in beef cattle breeds
- affected calves are often aborted, and exhibit disproportionate dwarfism, short vertebral column, large head with short muzzle, protruding tongue, and large abdominal hernia
7
Q
What is Wobbler’s Syndrome?
A
- cervico-vertebral stenotic myelopathy
- localized skeletal dysplasia, most common in horses and large dogs
- results in dynamic or static compression of cervical spinal cord by abnormal cervical vertebrae
8
Q
What is osteopetrosis?
A
- metaphyseal dysplasia
- inherited disease caused by osteoclast failure to reabsorb the primary spongiosa
- results in increased bone density, and lack of medullary spaces
- animals often present aplastic anemia
- bones more susceptible to fracture
9
Q
What is congenital cortical hyperostosis?
A
- autosomal recessive inherited condition in pigs
- limbs appear swollen due to excessive deposition of radiating trabeculae on periosteal surface, and blockage of local lymphatic circulation
- most born dead, or die quickly
10
Q
What is amelia?
A
absence of a limb
11
Q
What is hemimelia?
A
absence of the distal half of a limb
12
Q
What is polymelia?
A
supernumerary limbs
13
Q
What is phocomelia?
A
absence of proximal portion of a limb
14
Q
What is micromelia?
A
abnormally small or short limbs
15
Q
What is syndactylia?
A
fusion of the digits
16
Q
What is lordosis?
A
ventral deviation of vertebral column
17
Q
What is kyphosis?
A
dorsal deviation of vertebral column
18
Q
What is scoliosis?
A
lateral deviation of vertebral column
19
Q
Describe a valgus deformity
A
- lateral deviation (outward)
- knock kneed
20
Q
Describe a varus deformity
A
- medial deviation (inward)
- bow legged
21
Q
What are the possible etiologies of metabolic bone diseases?
A
- nutritional
- hormonal
- disuse
- toxic
22
Q
Describe osteoporosis
A
- metabolic bone disease
- characterized by osteopenia (decreased amount of bone tissue)
- the bone that is present is normal
- reduction in thickness of cortical bone, and decreased number of trabeculae in cancellous bone
23
Q
What are the etiologies of osteoporosis?
A
- nutritional: starvation, Cu or Vitamin C deficiency
- aging: reabsorption outpaces bone formation
- disuse
24
Q
What is Rickets?
A
- metabolic bone disease affecting young, growing animals
- defective calcification of osteoid, and defective endochondral ossification
- etiology typically involves vitamin D or phosphorus deficiency
25
Explain the gross lesions of Rickets
- irregular thickening of growth plates with tongues of uncalcified cartilage extending into the metaphysis
- widening of growth plates, enlarged ends of long bones
- enlargement of costochondral junctions (rachitic rosary)
- weight-bearing bones become bowed
- hemorrhages beneath cartilage or in growth plates
26
Describe osteomalacia
- a disease of grown animals
- failure in mineralization of osteoid, primarily due to vitamin D or P deficiency
- unmineralized osteoid is resistant to osteoclast resorption, accumulates in bone
27
Describe Fibrous osteodystrophy
- metabolic bone disease characterized by extensive bone resorption and replacement by fibrous connective tissue and poorly mineralized immature bone
- caused by hyperparathyroidism
- decreased calcium and increased phosphorus, resulting in increased PTH
28
Describe primary hyperparathyroidism
- associated with functional parathyroid adenomas in dogs
- exhibit hypercalcemia and hypophosphatemia
- lesions include FO, thyroid C-cell hyperplasia, hypercalcemic nephropathy, and metastatic mineralization of soft tissues
29
Describe secondary hyperparathyroidism
nutritional: dietary deficiency of Ca, excess P, or deficiency of vitamin D
- affects young, growing animals
renal: P retention due to loss of glomerular function, and inadequate synthesis of calcitriol by the kidney
- bones swollen and firm, rubber jaw
30
What happens in lead poisoning?
- lead interferes with osteoclastic acitivity
| - subtle bone lesions > increased bone density in metaphysis > lead line
31
What happens in fluoride toxicosis?
- affects normal metabolism of bone and teeth
- soft dark-brown discolored teeth that wear down easily
- bones exhibit periosteal hyperostosis
- in herbivores
32
What causes hypervitaminosis A?
| What happens?
- cats consume high amounts of bovine livers for a long period of time
- deforming cervial spondylosis
- develop osteophyte formation around joints of cervical vertebrae, shoulder, and elbow
33
What is a sequestrum?
a piece of necrotic bone isolated from the remaining viable bone
34
What is an involucrum?
- a layer of granulation tissue and reactive bone
| - formed when there is an attempt to wall off the sequestrum
35
What is a comminuted fracture?
fragmented fracture
36
What does it mean when a fracture is avulsed?
caused by the pull of a ligament/tendon at its insertion into the bone
37
What is a microfracture/infraction?
- fracturing of trabeculae without external deformation of cortical bone
38
What are possible complications with bone fractures?
- bone necrosis and formation of a sequestrum
- non-union fracture: pseudoarthrosis formation (false joint)
- osteomyelitis
- cachexia
