Childrens Ortho

Question 1

A child’s skeleton has how many bones?

Answer 1

270

Question 2

What does the physis describe?

Answer 2

The areas from which long bone growth occurs post-natally

Question 3

How do flat bones develop in utero?

Answer 3

Intramembranous ossification
Mysenchymal cells -> bone

Question 4

How do long bones develop in utero?

Answer 4

Endochondral ossification
Mesenchymal cells -> cartilage -> bones

Question 5

Outline the process of intramembranous ossification

Answer 5

1. Condensation of mesenchymal cells which differentiate into osteoblasts - Ossification centre forms
2. Secreted osteoid traps osteoblasts which become osteocytes
3. Immature woven trabecular matrix and periosteum form
4. Compact bone develops superficial to cancellous bone. Crowded blood vessels condense into red bone marrow

Question 6

What bones are formed by intramembranous ossification?

Answer 6

Flat bones of skull, clavicle and mandible

Question 7

Intramembranous ossification describes the bone development from what origin?

Answer 7

Fibrous membranes

Question 8

What is the cell templates for intramembranous ossification?

Answer 8

Mesenchymal cells

Question 9

What is endochondral ossification?

Answer 9

Development of long bone by replacing the hyaline cartilage precursor

Question 10

Does endochondral or intramembranous ossification take longer?

Answer 10

Endochondral

Question 11

What are primary ossification centres?

Answer 11

Sites of pre-natal bone growth through endochondral ossification from the central part of the bone

Question 12

What are secondary ossification centres?

Answer 12

Occurs post-natal after the primary ossification centre and long bones often have several (the physis)

Question 13

Outline the process of primary endochondral ossification

Answer 13

PRIMARY endochondral ossification1. Mesenchymal differentiation at the primary centre2. The cartilage model of the future bony skeleton forms3. Capillaries penetrate cartilage.> Calcification at the primary ossification centre - spongy bone forms> Perichondrium transforms into periosteum4. Cartilage and chondrocytes continue to grow at ends of the bone5. Secondary ossification centres develop with its own blood vessel and calcification at the proximal and distal end - calcification of the matrix6. Cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.

Question 14

Outline the process of secondary ossification

Answer 14

ossification occurs at the physis
• basically interstitial growth
• proliferation of chondrocytes and the subsequent calcification of the extracellular matrix into immature bone that is then subsequently remodelled

Question 15

What is the role of secondary ossification in children?

Answer 15

• physis is responsible for the skeletal growth of a child
• any congenital malfunction to this area or acquired insult - whether it is traumatic/infective or otherwise will therefore have a subsequent impact on growth of the child

Question 16

What differences are there between child and adult skeleton?

Answer 16

Elasticity
Physis
Speed of healing
Remodelling

Question 17

Are a child’s bones more or less elastic than an adults, why, and what affects does this have?

Answer 17

More elastic
Increased density of Haversian canals as bones are more metabolically active
Therefore can get: buckle fractures, plastic deformity, green stick fractures

Question 18

When does physeal closure complete in boys vs girls

Answer 18

Boys 18-19
Girls 15-16

Question 19

What affect can physeal injuries have on a child?

Answer 19

Can lead to growth arrest which can lead to deformity

Question 20

The speed of healing and remodelling potential of bones is dependent on what?

Answer 20

Location and age of the patient

Question 21

How are physical injuries categories?

Answer 21

Salter-Harris

Question 22

Outline the Salter-Harris classification of physeal injuries (SALT)

Answer 22

1.Physeal separation
2.Fracture transverses physis and exits metaphysis (above)
3.Fracture transverses physis exits epiphysis (Lower)
4.Fracture passes Through epiphysis, physis, metaphysis
5.Crush injury to physis

Question 23

Which Salter-Harris classification of physeal injury has to highest risk of growth arrest?

Answer 23

Crush injury to physis, increases from 1-5

Question 24

Which type of Salter-Harris physeal injury is most common?

Answer 24

Type 2 - fracture transverses physis and exits metaphysis (above)

Question 25

What are the four R/s of fracture management?

Answer 25

Resuscitate
Reduce
Restrict
Rehabilitate

Question 26

What is developmental dysplasia of the Hip?

Answer 26

Group of disorders of the neonatal hip where’d the head of the femur is unstable or incongruous in relation to the acetabulum