Chapter 39

Question 1

Which statement is true comparing the ossification of the scapula and the
humerus:
A. The scapula and the humerus both develop with endochondral ossification
but the medullary canal is underdeveloped in the scapula
B. The scapula develops by intramembranous ossification without forming a
cartilage template.
C. The humerus develops by intramembranous ossification without forming a
cartilage template.
D. Whereby the humerus develops with one primary and two secondary
ossification centers, the scapula develops only one primary ossification centre

Answer 1

B. The scapula develops by intramembranous ossification without forming a
cartilage template.

Question 2

Which statement best describe a classic salter harris type 1 fracture
A. The fracture is located in the resting zone of the epihyseal growth plate
and damage to the progenitor cells is likely to occur
B. The fracture is usually located in the hypertrophic zone. Manipulation of
the metaphyseal bone fragment should proceed carefully so as not to
damage the reserve zone of chondrocytes, necessary for further growth
C. The fracture is usually located in the hypertrophic zone. Manipulation of
the epiphyseal bone fragment should proceed carefully so as not to
damage the reserve zone of chondrocytes, necessary for further growth
D. The fracture is usually located in the calcification zone. Manipulation of the
metaphyseal bone fragment should proceed carefully so as not to damage
the reserve zone of chondrocytes, necessary for further growth

Answer 2

C. The fracture is usually located in the hypertrophic zone. Manipulation of
the epiphyseal bone fragment should proceed carefully so as not to
damage the reserve zone of chondrocytes, necessary for further growth

Question 3

Which of these statement is true (multiple answers can be true):
A. Cortical bone can withstand higher strain then cancellous bone
B. Cancellous bone can withstand greater strain then cortical bone
C. Cancellous bone can withstand strain up to2%
D. Cancellous bone can withstand strain up to 75%

Answer 3

B. Cancellous bone can withstand greater strain then cortical bone

D. Cancellous bone can withstand strain up to 75%

Question 4

4.Define interfragmentary strain in the context of fracture biology.

A. Strain is determined by measuring the magnitude of change in the size of
a fracture gap after applying load and dividing by the size of the fracture
gap
B. Strain is determined by measuring the load applied to a fracture and
dividing by the sie of the fracture gap
C. Strain is determined by the activity of the patient postoperatively
D. Strain is determined by measuring the magnitude of change in the size of
a fracture gap after applying physiologic loading and dividing by the size of
the fracture gap

Answer 4

A. Strain is determined by measuring the magnitude of change in the size of a fracture gap after applying load and dividing by the size of the fracture
gap

Question 5

Describe Wolff’s law

A. Wolff’s law describes how mechanical stress applied to bone can develop
in to different fracture patterns.
B. Wolff’’s law describes how plate size affect the stability of a fracture repair.
C. Wolff’s law describes how bone remodels in juvenile animals in response
to its mechanical environment.
D. Wolff’s law describes how bone remodels in response to its mechanical
environment.

Answer 5

D. Wolff’s law describes how bone remodels in response to its mechanical
environment.

Question 6

How does secondary bone formation decrease interfragmentary strain
A. Cutting cones slowly transverse the fracture gap stiffening the hematoma
and therefore reducing strain
B. Bridging the fracture gap with an external callus
C. Higher stress on the facture ends induce osteoproduction and stiffer
fracture ends
D. Osteoclast remove dead bone rom the fracture ends

Answer 6

B. Bridging the fracture gap with an external callus

D. Osteoclast remove dead bone rom the fracture ends

Question 7

List the five steps of secondary bone healing:
A. inflammation-intramembranous ossification-soft callus
formation(chondrogenesis)-hard callus formation (endochondral
ossification)-bone remodeling
B. hematoma formation-inflammation- soft callus formation- intramembranous
ossification- hard callus formation
C. inflammation -soft callus formation(chondrogenesis)-hard callus formation
(endochondral ossification)-bone remodeling – medullary canal reopening
D. neovascularisation- soft callus formation(chondrogenesis)-cartilage
deposit- hard callus formation (endochondral ossification)-bone
remodeling

Answer 7

B. hematoma formation-inflammation- soft callus formation- intramembranous
ossification- hard callus formation

Question 8

Explain “elastic plate osteosynthesis” and its possible advantages in juvenile
dogs
A. Elastic plate osteosynthesis utilizes the elastic properties of juvenile bone
to negate the need for adequate contouring of the plate (the bone matches
the plate)
B. A stiffer implant should be chosen in juvenile patients to counteract the
elastic properties of juvenile bone
C. The compliance of the plate bone construct is increased to decrease the
stress on bone screw interfaces
D. The compliance of the plate bone construct is decreased to decrease the
stress on bone screw interfaces

Answer 8

C. The compliance of the plate bone construct is increased to decrease the
stress on bone screw interfaces