a. Increase in skeletal mass
b. Decrease in the amount of mineralized bone
c. No change in the mineral to matrix ratio
d. Decrease in the cortical diameter of a long bone
e. Increase in bone mineral density by DEXA scanning
2. Paget’s disease of bone is:
a. A disease of decreased bone turnover
b. Common in young males
c. Rarely seen in the skull
d. Is most common in the foot
e. None of the above
3. Bone as a tissue:
a. Is largely devoid of cells
b. Contains more water than cartilage
c. Contains type II collagen in its ground substance
d. Depends on its lamellar structure for strength
e. Has amorphous calcium phosphate as its major mineral
constituent
4. Neurologic diseases such as cerebral palsy, polio, and spina bifida
damage the musculoskeletal system. This damage is primarily the
result of:
a. Muscle imbalance
b. Lack of sensation
c. Recurrent infections
d. Defects in sensory motor integration
e. Mental retardation
5. Causes of rickets include all except:
a. Sprue
b. Genetic renal tubular defects
c. Vitamin C deprivation
d. Dilantin therapy
e. Renal phosphate retention
6. Hyaline cartilage:
a. Is a hypocellular tissue
b. Depends on the glycosaminoglycans for resiliency
c. Is primarily water by weight
d. Is found in diarthrodial joints
e. All the above
7. Achondroplasia:
a. Is an aberration of epiphyseal growth
b. Is the most common skeletal dysplasia
c. Is characterized by knock knees
d. Is often associated with mental retardation
e. Is fatal in infancy
8. Rheumatoid arthritis:
a. Is a disease of the articular cartilage
b. Typically results in hyperostosis around the joints
c. Commonly causes early fibrosis of the synovium
d. Is considered a noninflammatory arthritis
e. Radiographically is characterized by juxtaarticular osteopenia
9. All the following are characterized by generalized osteopenia on the
radiograph except:
a. Gout
b. Hyperparathyroidism
c. Osteomalacia
d. Multiple myeloma
e. Osteoporosis
10. Neuropathic arthritis is the result of proprioceptive sensory loss
in conjunction with microtrauma and a component of vasomotor
instability. All the following can cause a neuropathic arthritis
except:
a. Syphilis
b. Polio
c. Diabetes
d. Heavy metal intoxication
e. Leprosy
11. Avascular necrosis of bone:
a. Can result from exogenous steroid administration
b. Is characterized by relative radiodensity
c. Can involve the femoral head and talus among other bones
d. Can be associated with sickle cell disease
e. All the above
12. Collagen:
a. Is a proteoglycan
b. Is important for the compressive strength of cartilage
c. Is synthesized by chondroblasts and osteoblasts
d. Is a large ring molecule
e. Is not a cross-linked molecule
ANSWERS
1. Answer: c
Osteoporosis results from net bone resorption. Therefore, there is net loss
of bone. There is no change in the standard mineral to matrix ratio. Cortical
diameter increases and bone mineral density (BMD) by dual-energy
X-ray absorptiometry (DEXA) decreases.
2. Answer: e
Paget’s is a disease of typically older males and results from increased bone
turnover. Bone formation and bone resorption both increase.
3. Answer: d
The mechanical properties of bone depend largely on its unique integrated
lamellar structure. Apatite is the primary mineral and the collagen is type
I. (Remember, the word ONE is found in BONE.)
4. Answer: a
Without doubt, the common denominator in these and other similar diseases
is muscle imbalance. This imbalance results in abnormal agonist–
antagonist relationships, leading to joint contractures, fixed deformities,
subluxation, and dislocation. In cerebral palsy (CP), the imbalance is
spastic muscle versus more spastic muscle, in spina bifida the imbalance
is largely weak muscle versus absent muscle, and in polio the imbalance is
absent and weak muscle versus normal muscle. Nevertheless, the net result
is the same: muscle imbalance.
5. Answer: c
Vitamin C deprivation causes the condition known as scurvy. Dilantin is
toxic to liver microsomes, hence blocking normal pathways of vitamin D
metabolism.
6. Answer: e
All are typical characteristics of hyaline cartilage.
7. Answer: b
Achondroplasia is an abnormality of the proliferating zone of the physis
resulting primarily in short stature. Typically, these individuals have bowlegs,
kyphotic spines, and are of normal intelligence.
8. Answer: e
Rheumatoid arthritis is a synovial disease characterized by hyperemia and
hyperplasia of the synovium. There is NO repair attempt made; hence, all
the changes around the joint are atrophic. Vascular hyperemia is the mechanism
of resorption on both sides of the joint.
9. Answer: a
Gout produces typically focal changes around the joints as a result of the
deposition of urate.
10. Answer: b
Polio does NOT affect the sensory nerves. It is purely a motor neuropathy;
therefore, neuropathic joints are not seen.
11. Answer: e
All are typical of avascular necrosis (AVN). The talus, proximal femur,
and scaphoid all have a retrograde blood fl ow, making them vulnerable to
AVN.
12. Answer: c
Collagen is a linear protein molecule that is highly cross-linked at multiple
sites in the triple helix called tropocollagen. Both cell populations can
synthesize the molecule despite the fact that the amino acid sequence is
different. Type I collagen is found in bone and type II collagen in cartilage.
The primary mechanical role of collagen is to provide tensile strength to
the tissue.
