DEXA Anatomy & Physiology of Bone Structure 4

Question 1

The femoral neck is a critical DEXA measurement site primarily because it:

Accepted Answer

Is a common fracture site with high morbidity and is rich in trabecular bone

Answer

The femoral neck is a major osteoporotic fracture site and contains significant trabecular bone, making it a key DEXA site for fracture risk assessment.

Question 2

Bone tissue that is rapidly deposited during fracture healing or in Paget's disease, characterized by disorganized collagen fibers, is called:

Accepted Answer

Woven (fiber) bone

Answer

Woven bone has randomly oriented collagen fibers and is weaker than lamellar bone; it is laid down quickly in response to injury and is later remodeled.

Question 3

Volkmann's canals in compact bone run in what orientation relative to Haversian canals?

Accepted Answer

Perpendicular (transverse/oblique)

Answer

Volkmann's canals run perpendicular to the long axis of bone, connecting adjacent Haversian canals and the periosteum to the medullary cavity.

Question 4

Which hormone directly inhibits osteoclast activity and is secreted by thyroid parafollicular (C) cells?

Accepted Answer

Calcitonin

Answer

Calcitonin, secreted by thyroid C cells, inhibits osteoclast-mediated bone resorption and lowers serum calcium, opposing the effects of PTH.

Question 5

In a long bone, the diaphysis refers to:

Accepted Answer

The shaft (midportion) of the long bone

Answer

The diaphysis is the cylindrical shaft of a long bone, composed predominantly of compact cortical bone surrounding the medullary cavity.

(DEXA) DEXA Bone Density Scan Certification Practice Test

(DEXA) DEXA Bone Density Scan Certification Practice Test

DEXA Anatomy & Physiology of Bone Structure 4