Musculoskeletal Pathology I

Question 1

What is the skeleton?

Answer 1

• Bones, Joints and their supporting ligaments
• responsible for supporting the body and enabling movement

Question 2

What are the two major factors that regulate deposition and resorption of bone?

Answer 2

• Mechanical forces
• Hormonal agents e.g- calcitriol, PTH, oestrogen, (modulated resorption via osteoclasts

Question 3

How does bone modelling occur?

Answer 3

bones are shaped or reshaped via the independent action of osteoblasts and osteoclasts

Question 4

How does bone remodelling occur?

Answer 4

osteoblasts and osteoclasts work sequentially in the same bone remodelling unit
* the adult skeleton is renewed throughout life
* most prominent on cancellous bone surfaces

Question 5

What does disruption of endochondral ossification affect?

Answer 5

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)

Question 6

How does bone fracture occur?

Answer 6

Forces exceed a bones ability to compensate (either too fast or too strong)

Question 7

What is achondroplasia?

Answer 7

absence of cartilage development

Question 8

What is chondrodysplasia?

Answer 8

disorder of cartilage development

Question 9

What is skeletal dysplasia?

Answer 9

disorder of skeletal development

Question 10

What is brachycephaly?

Answer 10

shortening of the head

Question 11

What is brachygnathia?

Answer 11

shortening of the jaw

Question 12

What is palatoschisis?

Answer 12

Cleft Palate

Question 13

What is prognathia?

Answer 13

abnormal projection of the jaw

Question 14

What is Pectus excavatum?

Answer 14

concavity of the sternum

Question 15

What is Kyphosis?

Answer 15

abnormal dorsal curvature of spinal column

Question 16

What is Lordosis?

Answer 16

abnormal ventral curvature of the spinal column

Question 17

What is scoliosis?

Answer 17

lateral deviation of spinal column

Question 18

What is block vertebrae?

Answer 18

failure of two vertebral bodies to separate

Question 19

What is hemivertebrae?

Answer 19

failure of two halves of vertebral body to fuse

Question 20

What is spina bifida?

Answer 20

failure of dorsal midline closure

Question 21

What is amelia?

Answer 21

absence of one or more limbs

Question 22

What is Hemimelia?

Answer 22

absence of the distal part of the limb

Question 23

What is Micromelia?

Answer 23

presence of abnormally small limbs

Question 24

What is notomelia?

Answer 24

accesory limb attached to the back

Question 25

What is peromelia?

Answer 25

congenital deformity of the limbs

Question 26

What is phocomelia?

Answer 26

absence of the proximal portion of one or more limbs

Question 27

What is Adactyly?

Answer 27

absence of a digit

Question 28

What is Dactylomegaly?

Answer 28

abnormally large digits

Question 29

What is Ectrodactyly?

Answer 29

partial or complete absence of a digit

Question 30

What is Polydactyly?

Answer 30

presence of supernumerary digits

Question 31

What is polypodia?

Answer 31

presence of supernumerary feet

Question 32

What is syndactyly?

Answer 32

fusion of digits

Question 33

What is osteogenesis imperfecta?

Answer 33

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)

Question 34

What causes osteogenesis imperfecta?

Answer 34

Mutation in COL1A1 and COL1A2 genes, the severity is on a spectrum depending on what alleles are inherited

Question 35

What is osteopetrosis?

Answer 35

disorder of bone resorption, characterised by increased bone density * failure of resorption by osteoclasts

Question 36

What are the two causes of osteopetrosis?

Answer 36

* Inherited - mutation that impairs osteoclats formation * Infectious- in-utero BVD or FeLV infection

Question 37

What is congenital cortical hyperostosis?

Answer 37

* disorder of bone remodelling * autosomal recessive disease of newborn pigs * abnormal radial periosteal bone formation

Question 38

What is craniomandibular osteopathy?

Answer 38

disorder of bone modelling, mainly affects WHWT and Scottish Terriors

Question 39

When does craniomandibular osteopathy become apparant?

Answer 39

4-7 months then regresses

Question 40

What is chondrodysplasia?

Answer 40

disorder of endochrondral ossification

Question 41

What does chondrodysplasia result in?

Answer 41

disproportionate dwarfism

Question 42

What mutation does FGFR3 cause?

Answer 42

spider lamb chondrodysplasia

Question 43

What breeds does FGFR4 effeect? ## Footnote causes chondrogenesis

Answer 43

Dachshund, Pekinese, Basset Hound

Question 44

What does osteochrondrosis latens look like histologically?

Answer 44

Well demarcated area of necrosis in cartilage

Question 45

What is osteochondrosis dissecans?

Answer 45

traumatic clefting through the area of necrosis * fragments of cartilage break off * can resolve without clefting

Question 46

What is cervical vertebral myelopathy?

Answer 46

'wobbler syndrome' disorder of endochondral ossification

Question 47

What does cervical vertebral myelopathy cause?

Answer 47

* Neurological disease secondary to compression of the spinal cord and therefore causes abnormally developed cervical vertebrae

Question 48

What species are most affected by wobbler syndrome?

Answer 48

Horses and large breed dogs

Question 49

What is osteoporosis?

Answer 49

reduced bone mass, porous, thin and fragile

Question 50

What are the causes of osteoporosis

Answer 50

* Protein calorie malnutrition * immobilisation * glucocorticoid excess * oestrogen or androgen deficiency * advanced age

Question 51

What is Ricketts?

Answer 51

Failure of bone mineralisation with subsequent deformities and fractures in the growing skeleton

Question 52

What causes Ricketts?

Answer 52

Vitamin D deficiency and phosphorus deficiency

Question 53

What is fibrous osteodystrophy?

Answer 53

decreased bone mass, increased pliability due to replacement by fibro-osseous tissue

Question 54

What causes fibrous osteodystrophy?

Answer 54

decreased bone mass, increased pliabilty due to replacement by fibro-osseous tissue

Question 55

What causes fibrous osteodystrophy?

Answer 55

Hyperparathyroidism

Question 56

What is an osteophyte?

Answer 56

nodular, benign growth at the margins of a synovial joint

Question 57

What is an Enthesophyte?

Answer 57

ossification of a tendon or ligament

Question 58

What is a Hyperostosis?

Answer 58

diameter of the bone has increased

Question 59

What is an osteochondroma?

Answer 59

multiple cartilaginous exostoses

Question 60

What are bone cysts

Answer 60

appear radiographically as well demarcated

Question 61

What occurs when the metaphyseal trabeculae is affected?

Answer 61

Decreased rate of elongation of the bone

Question 62

What is Hypertrophic osteopathy?

Answer 62

Progressive, often bilateral, periosteal new-born formation in diaphysis and metaphysis

Question 63

What is static stenosis?

Answer 63

Constant compression due to anatomic stenosis of the spinal cord also called cervical vertebral static stenosis

Question 64

What is dynamic stenosis?

Answer 64

compression only during movement/ flexion also called cervical vertebral instability

Question 65

What type of stenosis affects dogs?

Answer 65

Static

Question 66

What is characteristic about a lead toxin lesion?

Answer 66

Characteristic line parallel to the growth plate

Question 67

What is an exostosis?

Answer 67

nodular bony growth projecting from a bones surface

Question 68

What is an ensotosis?

Answer 68

Bony growth from within the medullary cavity

Question 69

What is hypertrophic osteopathy called in humans?

Answer 69

Maries Disease

Question 70

What does aneurysmal mean?

Answer 70

Filled with blood or serosanguinous fluid (not lined by endothelium)