|
Year |
2007 |
|---|---|
|
Question Number |
113 |
|
Category |
Pediatric Orthopaedics |
Question
Which of the following growth plate zones is most commonly associated with growth plate fractures?
1- Resting zone
2- Zone of proliferation
3- Zone of hypertrophy
4- Zone of primary bone formation and vascular ingrowth
5- Germinal layer
Figures
Answer (click for answer)
The correct answer is 3- Zone of hypertrophy
The zone of hypertrophy is most commonly associated with growth plate fractures. In the hypertrophic zone of the growth plate, cell division ceases and the chondrocytes begin to terminally differentiate. Terminal differentiation is associated with a large increase in cell volume, a marked increase in alkaline phosphatase enzyme activity, and synthesis and secretion of type-X collagen. The enlarged chondrocytes have a decreased ability to withstand shearing, bending and tension forces. The hypertrophic zone is therefore the weakest portion of the growth plate and most fractures occur here.
Reference: