Colleague's model Your model 85 yo woman dob = 32 mm dic=27mm dob = 34 mm dic =29mm 85yo man dob = 34 mm dic=27mm dic dob Intramedullary Canal Cortical Bone Figure 1: Assume a simplified bone modeled as a hollow cylinder of cortical bone only. Q3A Calculate the area moment of inertia of the cortical bone model for the 85 year old man and for both models of the 85 year old woman.
Colleague's model Your model 85 yo woman dob = 32 mm dic=27mm dob = 34 mm dic =29mm 85yo man dob = 34 mm dic=27mm dic dob Intramedullary Canal Cortical Bone Figure 1: Assume a simplified bone modeled as a hollow cylinder of cortical bone only. Q3A Calculate the area moment of inertia of the cortical bone model for the 85 year old man and for both models of the 85 year old woman.
Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
Related questions
Question
![Changes in cortical bone density and bone geometry occur with aging in both men and women (Table 1 from Russo
2003). These changes manifest as decreased bone strength, which has the clinical impact of increasing the risk of fracture with increasing
age. However, elderly men are much less prone to fracture than elderly women. It has been suggested that age-related bone loss is the
consequence of endosteal bone resorption resulting in changes in bone geometry (~2mm less cortical bone thickness in women as they
age) and contributing to relative differences in fracture risk between men and women. Cortical bone area decreases in women between
the ages of 20 and 85, whereas there is no significant change in cortical bone area for men over the same age range (Table 1).
Table 1: Changes in bone density and cortical bone area - from Italian population of 612 men and 693 women
Age group (years)
ANOVA
20-39
Total bone density 4% (mg/cm³)
Men
342.344.9
Women
307.134.8
Cortical bone area 38% (mm²)
Men
318.9+47.9
Women 288.8+41.2
40-49
Colleague's model
Your model
315.2±38.2
286.9±27.9
329.1+54.9
289.2 34.3
50-64
85 yo woman
dob=32 mm
dic=27mm
dob = 34 mm
dic =29mm
302.131.8
274.6±40.3
319.756.8
287.9 +53.5
85yo man
65-74
dob = 34 mm
dic=27mm
288.6 35.5
253.932.2
324.9±42.2
281.1+52.7
75-84
290.0+ 45.4
241.636.8
326.846.0
265.0 60.0
85+
Models: You and your new work colleague decide to estimate the bending stiffness of bones in 85+ year old women and men by
calculating the area moment of inertia for the diaphyseal shaft of an idealized long bone. You each decide to model it as a long hollow
cylinder consisting of a cortical shell (outer bone diameter dob) surrounding a hollow intramedullary canal (with diameter dic). You estimate
the cortical thickness as 7 mm for the model of the male bone. Your colleague assumes bone loss occurs at the outer bone surface (outer
diameter) and therefore reduces the outer diameter 2 mm for the woman model. You assume the bone loss occurs at the inner cortical
bone surface (inner diameter) and therefore increase the inner diameter 2 mm for the woman model.
284.8±45.1
229.233.1
332.751.2
230.272.4
p<0.0001
p<0.0001
dic
p=0.28
p<0.0001
dob
14.
Intramedullary
Canal
Cortical Bone
Figure 1: Assume a simplified bone modeled.
as a hollow cylinder of cortical bone only.
Q3A Calculate the area moment of inertia of the cortical bone model for the 85 year old man and for both models
of the 85 year old woman.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fa9e37a56-aa3e-46d8-94dc-6e108bf702ca%2F69b93120-a02a-4419-9e39-311d59eed6ec%2Fl21qcx7_processed.jpeg&w=3840&q=75)
Transcribed Image Text:Changes in cortical bone density and bone geometry occur with aging in both men and women (Table 1 from Russo
2003). These changes manifest as decreased bone strength, which has the clinical impact of increasing the risk of fracture with increasing
age. However, elderly men are much less prone to fracture than elderly women. It has been suggested that age-related bone loss is the
consequence of endosteal bone resorption resulting in changes in bone geometry (~2mm less cortical bone thickness in women as they
age) and contributing to relative differences in fracture risk between men and women. Cortical bone area decreases in women between
the ages of 20 and 85, whereas there is no significant change in cortical bone area for men over the same age range (Table 1).
Table 1: Changes in bone density and cortical bone area - from Italian population of 612 men and 693 women
Age group (years)
ANOVA
20-39
Total bone density 4% (mg/cm³)
Men
342.344.9
Women
307.134.8
Cortical bone area 38% (mm²)
Men
318.9+47.9
Women 288.8+41.2
40-49
Colleague's model
Your model
315.2±38.2
286.9±27.9
329.1+54.9
289.2 34.3
50-64
85 yo woman
dob=32 mm
dic=27mm
dob = 34 mm
dic =29mm
302.131.8
274.6±40.3
319.756.8
287.9 +53.5
85yo man
65-74
dob = 34 mm
dic=27mm
288.6 35.5
253.932.2
324.9±42.2
281.1+52.7
75-84
290.0+ 45.4
241.636.8
326.846.0
265.0 60.0
85+
Models: You and your new work colleague decide to estimate the bending stiffness of bones in 85+ year old women and men by
calculating the area moment of inertia for the diaphyseal shaft of an idealized long bone. You each decide to model it as a long hollow
cylinder consisting of a cortical shell (outer bone diameter dob) surrounding a hollow intramedullary canal (with diameter dic). You estimate
the cortical thickness as 7 mm for the model of the male bone. Your colleague assumes bone loss occurs at the outer bone surface (outer
diameter) and therefore reduces the outer diameter 2 mm for the woman model. You assume the bone loss occurs at the inner cortical
bone surface (inner diameter) and therefore increase the inner diameter 2 mm for the woman model.
284.8±45.1
229.233.1
332.751.2
230.272.4
p<0.0001
p<0.0001
dic
p=0.28
p<0.0001
dob
14.
Intramedullary
Canal
Cortical Bone
Figure 1: Assume a simplified bone modeled.
as a hollow cylinder of cortical bone only.
Q3A Calculate the area moment of inertia of the cortical bone model for the 85 year old man and for both models
of the 85 year old woman.
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