ORTHOPEDIC MCQS ONLINE QUESTION BANK H1C

ORTHOPEDIC MCQS ONLINE QUESTION BANK H1C


Which of the following fractures occurs through a single application of force:
1) A minimally displaced femoral neck fracture in a long distance runner
3) A fifth rib fracture in a collegiate rower
2) A second metatarsal fracture in a Naval Academy midshipman
5) A proximal one-third posterior tibial cortex fracture in a long distance runner
4) A short spiral humerus fracture in a baseball catcher
The femoral neck fracture, metatarsal fracture, rib fracture, and the tibial fracture are stress fractures that result from repetitive loading.
In contrast, the humeral fracture in the baseball catcher is secondary to failure of the humerus secondary to a pure torsional force. Long bones are at their weakest when loaded in pure torsion.
Correct Answer: A short spiral humerus fracture in a baseball catcher

674. (872) Q2-1135:
Which of the following statements is true concerning the vascularity at a fracture site:
1) Periosteal blood vessels are capable of supplying the endosteal region.
3) Reamed intramedullary rods do not significantly interrupt endosteal blood supply.
2) Fracture site blood flow peaks at 2 weeks.
5) In animal studies, blood flow is greater at 42 days in rodded vs. plated tibias.
4) In animal studies, blood flow is greater at 120 days in plated vs. rodded tibias.
In the normal long bone, the periosteal vessels supply the outer one-third of the cortex. The nutrient artery enters at the diaphysis of a long bone and has ascending and descending vessels that supply the inner two-thirds of the cortex.
Important points to remember:
The periosteal blood supply cannot supply the inner two-thirds of the cortex even if the endosteal blood supply has been interrupted, as in intramedullary reaming.
Blood flow markedly drops at the fracture site at the time of the fracture and peaks at 2 weeks.
Intramedullary reamed rods destroy the endosteal blood supply. In dog experiments, the blood supply is reconstituted to normal in 120 days.
In dog experiments, the blood supply is decreased in both plated and rodded tibias at 42 and 90 days. The decrease is greater in the rodded tibias.
The oxygen tension is low in the fracture hematoma and in the newly formed cartilage and bone. The oxygen tension is highest in the fibrous tissue. The hypoxic state favors cartilage formation.
6Correct Answer: Fracture site blood flow peaks at 2 weeks.
75. (873) Q2-1137:
Which of the following statements is true concerning molecular events at the site of a healing fracture:
1) Type II collagen production is lowest during the first 2 weeks.
3) Periosteal type III collagen serves as a substrate for migration of osteoprogenitor cells and capillary ingrowth.
2) Type I collagen production is highest during the first 2 weeks.
5) Types V and XI collagen control the maturation of mineralization crystals.
4) Type IX collagen initiates mineralization of type II collagen.
Important points to remember concerning molecular events at the fracture site:
Type II collagen production is highest during the first 2 weeks. Cartilage is the first tissue produced at the fracture site. The chondrocytes hypertrophy and release matrix vesicles that prepare the extracellular matrix for mineralization of the cartilage. Blood vessels grow into the hypertrophied cartilage cells and perivascular cells become osteoblasts and begin mineralization. This is the exact same process that occurs at the growth plate with formation of the primary and secondary spongiosa.
Type I collagen production is low during the first 2 weeks as cartilage is initially formed. Type I collagen production is highest as the cartilage is mineralized later.
Periosteal type III collagen serves as a substrate for the migration of osteoprogenitor cells and capillary ingrowth. Type IX collagen contributes to the mechanical stability of type II collagen.
Types V and XI collagen regulate the growth and orientation of types I and II collagen fibrils.
Correct Answer: Periosteal type III collagen serves as a substrate for migration of osteoprogenitor cells and capillary ingrowth.

676. (874) Q2-1138:
Which of the following statements is true concerning the molecular events involved in fracture healing:
1) Osteonectin plays a role in early ossification.
3) Osteopontin plays no role in normal bone remodeling.
2) Osteocalcin inhibits intramembranous bone formation.
5) Osteonectin is found in proliferating and hypertrophic chondrocytes rather than extracellular matrix.
4) Fibronectin inhibits cell migration and adhesion.
There are several noncollagenous proteins that are important in bone repair and regeneration:
Osteonectin â The gene for osteonectin is expressed at the onset of both intramembranous and enchondral ossification. It may play a role in the regulation of cell function in the early stages of ossification.
Osteocalcin â Osteocalcin is expressed in the fracture callus only by osteoblastic cells. This protein may have a role in intramembranous subperiosteal bone formation.
Osteopontin â This protein is found in the extracellular matrix and is important in cellular attachment. It is found in osteocytes and osteoprogenitor cells. Osteopontin may play a role in bone remodeling.
Fibronectin â This protein plays a role in early fracture healing and is found in the fracture hematoma within 3 days. Fibronectin mediates adhesion and migration. It is found in the fibrous portions of provisional matrices and in cartilage matrix. The potential role for this protein is the establishment of provisional fibers in cartilaginous matrices.
Correct Answer: Osteonectin plays a role in early ossification.
677. (933) Q2-1220:
Which of the following is not a clinical sign of rickets?
1) Irritability
3) Localized bone pain
2) Frontal bossing
5) Enlarged epiphyses
4) Short stature
Localized bone pain is not a common finding in rickets. In contrast, in osteomalacia, bone pain is very common. The features of rickets that one should remember include:
Apathy
Irritability
Short stature
Positive Gowers sign
Laxity
Frontal bossing
Rachitic rosary, Harrisonâs groove enlarged physes Correct Answer: Localized bone pain
1) Bone pain
3) Pathologic fractures
2) Brown tumors
5) Tetany
4) Renal stones
Features of primary hyperparathyroidism include bone pain, brown tumors, pathologic fractures, and kidney stones. Tetany is not a finding.
Here are some common features to remember: Common, incidence 1 in 500-1,000
Females (usually postmenopausal) greater than men, 3:1 Etiology
Benign, solitary adenoma (80%) Four gland parathyroid hyperplasia Parathyroid carcinoma (<0.5%)
Osteitis fibrosa cystica
Subperiosteal resorption of distal phalanx Tapering of distal clavicle
Bone cysts Brown tumors
Kidney stones
Peptic ulcer disease and pancreatitis Biochemical hallmarks
Hypercalcemia
Elevated PTH (phosphorus lower range of normal, 1/3 low) Neuromuscular syndrome
Easy fatigue, weakness, older than you seem
Bone mineral density - excellent marker of the disease - low in distal radius (cortical bone) and normal at vertebra (cancellous bone)
Treatment - neck exploration and removal of the parathyroid adenoma Correct Answer: Tetany
679. (935) Q2-1222:
Which of the following is the most likely origin for the greater medullary artery (Adamkiewicz artery):
1) Lower cervical segmental
3) Middle thoracic segmental
2) Upper thoracic segmental
5) Upper lumbar segmental
4) Lower thoracic segmental
The major part of the blood supply of the spinal cord is provided by the medullary or radicular arteries. The only feeder for the lower thoracic spine cord is the greater medullary artery or artery of Adamkiewicz (T9-T11).
One should remember that in the thoracic spine the right-sided approach is preferred to avoid the aorta and segmental artery of Adamkiewicz.
Correct Answer: Lower thoracic segmental
1) The anterior humeral circumflex artery
3) The posterior humeral circumflex artery
2) Axillary artery
5) Subscapular artery
4) Acromial branch of thoracoacromial artery
The humeral head has been shown to be perfused primarily by the anterolateral ascending branch of the anterior circumflex artery. This branch runs parallel to the lateral aspect of the tendon of the long head of the biceps and enters the humeral head where the proximal end of the intertubercular groove meets the greater tuberosity. The posterior circumflex artery provides only the posterior portion of the greater tuberosity and a small posteroinferior part of the head.Correct Answer: The anterior humeral circumflex artery
681. (937) Q2-1225:
A 4-year-old child injures his elbow and presents with swelling and limitation of voluntary movement. The radiographs show no obvious fracture, but it does show a Baumann angle of 71° and an elevation of the posterior fat pad. You tell the parents that this most likely represents:
1) A congenital anomaly with a valgus deformity of the elbow
3) A Salter I physeal separation
2) A medial epicondyle fracture
5) A variation of normal
4) An occult supracondylar fracture
Occult supracondylar fracture was the most common diagnosis assigned after careful study of a clinical series of elevated pediatric posterior fat pads.
The value for Baumann angle is normally 73° ± 6°. Nothing in this description suggests a congenital anomaly. Medial epicondyle fractures are extremely rare before 9 years of age.
Although a Salter I physeal separation is a possibility, it is a rare injury.
With an elevation of the posterior fat pad, there is increasing recognition that a fracture exists.
Correct Answer: An occult supracondylar fracture
682. (1049) Q2-1356:
The tibialis anterior muscle is principally innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
The tibialis anterior muscle is primarily innervated by the L4 nerve root. The tibialis anterior muscle also receives innervation from the L5 nerve root. Patients with a weak or absent tibialis anterior muscle will have a drop foot or a steppage gait. The tibialis anterior muscle causes dorsiflexion and inversion of the foot and ankle.Correct Answer: L4
683. (1050) Q2-1357:
The patellar tendon reflex is primarily transmitted through which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
Although the patellar tendon reflex is primarily transmitted through the L4 nerve root, the L2 and L3 nerve roots also contribute to the fibers. There is a weak reflex if the L4 nerve root is completely cut, even if there are still L2 and L3 fibers. Patellar tendon reflex is seldom completely absent unless the patient has primary muscle or anterior horn lesions.Correct Answer: L4
4) L5
It is important to remember the sensory dermatomes when examining patients. The medial aspect of the leg, foot, and great toe are supplied by the L4 nerve root. The tibial crest separates the L4 and L5 dermatomes on the leg.
Remember:
L4 Medial aspect of the leg, foot, and great toe L5 Lateral aspect of the leg and toes 2 to 4
S1 Lateral aspect of the fifth toe Correct Answer: L4
685. (1052) Q2-1359:
The extensor hallucis longus muscle is innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
The extensor hallucis longus muscle is primarily innervated by the L5 nerve root. The L5 nerve root innervates the following muscles:
Extensor hallucis longus muscle
Extensor digitorum longus and brevis muscles Gluteus medius muscle
Correct Answer: L5
686. (1053) Q2-1360:
The extensor digitorum longus and brevis muscles are primarily innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
The extensor digitorum longus and brevis muscles are primarily innervated by the L5 nerve root. The L5 nerve root innervates the following muscles:
Extensor hallucis longus muscle
Extensor digitorum longus and brevis muscles Gluteus medius muscle
Correct Answer: L5
1) L1
3) L3
2) L2
5) L5
4) L4
The gluteus medius muscle principally receives its innervation from the L5 nerve root through the superior gluteal nerve. Although the principal innervation is from L5, L4 and S1 nerve roots also contribute to the innervation.Correct Answer: L5
688. (1055) Q2-1362:
Testing of the L5 nerve root is accomplished through the:
1) Patellar tendon reflex
3) Tibialis posterior reflex
2) Achilles tendon reflex
5) Beevor sign
4) Superficial anal reflex
There is not a well-defined reflex arc for the L5 nerve root. The tibialis posterior reflex may be elicited at times, and this reflex is mediated through the L5 nerve root.
Remember the other reflexes as well: Patellar tendon L4
Achilles tendon S1
Superficial anal reflex S2, S3, and S4
Beevor sign refers to asymmetry of the segmental innervation of the rectus abdominus muscles. This is noted when a patient performs a sit-up and unilateral segmental nerve root loss is noted.Correct Answer: Tibialis posterior reflex
689. (1056) Q2-1363:
The skin on the lateral aspect of the leg and the dorsum of the foot between the second and fourth toes is innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
The L5 dermatome covers the skin on the lateral leg and dorsum of the foot from the lateral border of the great toe to the medial border of the little toe.
Remember:
L4 Medial aspect of the leg, foot, and great toe L5 Lateral aspect of the leg and toes 2 to 4
S1 Lateral aspect of the fifth toe Correct Answer: L5
4) S1
The peroneus brevis and longus muscles are principally innervated by the S1 nerve root through the superficial peroneal nerve. Although the innervation is principally through the S1 nerve root, the nerve is derived from the L5 and S2 nerve roots, as well.
Remember that the muscles principally innervated by the S1 nerve root include: Peroneus longus and brevis muscles
Gastrocnemius-soleus complex Gluteus maximus muscle
Correct Answer: S1
691. (1058) Q2-1365:
The medial and lateral gastrocnemius muscles principally receive their innervation through which of the following nerve roots:
1) L3
3) L5
2) L4
5) S2
4) S1
The medial and lateral gastrocnemius muscles are principally supplied by the S1 nerve root through the tibial nerve. There are also nerve fiber contributions from L5 and S2.
Remember that the muscles principally innervated by the S1 nerve root include: Peroneus longus and brevis muscles
Gastrocnemius-soleus complex Gluteus maximus muscle
Correct Answer: S1
692. (1059) Q2-1366:
The Achilles tendon reflex (ankle reflex) is transmitted through which of the following nerve roots:
1) L4
3) S1
2) L5
5) S3
4) S2
The Achilles tendon reflex is based upon the triceps muscle group (medial and lateral gastrocnemius muscles and soleus muscle) and is transmitted through the S1 nerve root.
Remember:
Patellar tendon reflex L4 Posterior tibial reflex L5 Achilles tendon reflex S1
Correct Answer: S1
1) L2, L3, and L4
3) L4, L5, and S1
2) L4 and L5
5) S2 and S3
4) L5, S1, and S2
The intrinsic muscles of the foot are innervated by the S2 and S3 nerve roots. These muscles are difficult to test. Clawing of the toes occurs with intrinsic muscle paralysis.
Remember the following nerve roots and the structures that they innervate:
L5, S1 and S2 Hip extension: Gluteus maximus muscle
L5, S1, and S2 Foot plantarflexion
L5, S1 and S2 Foot eversion
L4, L5, and S1 Hip abduction: Gluteus medius muscle
L4, L5 Foot dorsiflexion
L4, L5 Foot inversion
L2, L3, and L4 Hip adduction
L2, L3, and L4 Knee extension
L1, L2, and L3 Hip flexion: Iliopsoas muscle Correct Answer: S2 and S3
694. (1061) Q2-1368:
Perianal sensation is derived from which of the following nerve roots:
1) L2, L3, and L4
3) L5, S1, and S2
2) L3, L4, and L5
5) S2, S3, S4, and S5
4) S1, S2, and S3
Perianal sensation is derived from the S2, S3, S4, and S5 nerve roots. The sensory distribution is as follows:
S4-S5 Innermost perianal ring
S3 Middle perianal ring
S2 Outermost perianal ring Correct Answer: S2, S3, S4, and S5
1) T2
3) T7
2) T4
5) T12
4) T10
It is important to know the sensory segmental levels to localize pathologic processes. In addition to knowing the innervation of selected muscles and the deep tendon reflexes, a clinician should also know the sensory levels.
Remember:
T4 Nipple line
T7 Xiphoid process
T10 Umbilicus
T12 Groin
Correct Answer: T4
696. (1063) Q2-1370:
Which of the following sensory segmental levels corresponds to sensation at the xiphoid process:
1) T2
3) T7
2) T4
5) T12
4) T10
The skin over the xiphoid process area is innervated by the T7 nerve root.
It is important to know the sensory segmental levels to localize pathologic processes. In addition to knowing the innervation of selected muscles and the deep tendon reflexes, a clinician should also know the sensory levels.
Remember:
T4 Nipple line
T7 Xiphoid process
T10 Umbilicus
T12 Groin
Correct Answer: T7
1) T2
3) T7
2) T4
5) T12
4) T10
The skin of the umbilicus is innervated by the T10 sensory segmental level.
It is important to know the sensory segmental levels to localize pathologic processes. In addition to knowing the innervation of selected muscles and the deep tendon reflexes, a clinician should also know the sensory levels.
Remember:
T4 Nipple line
T7 Xiphoid process
T10 Umbilicus
T12 Groin
Correct Answer: T10
698. (1065) Q2-1372:
The skin over the groin is innervated by which of the following sensory segmental levels:
1) T2
3) T7
2) T4
5) T12
4) T10
The skin over the groin is innervated by the T12 sensory segmental level.
It is important to know the sensory segmental levels to localize pathologic processes. In addition to knowing the innervation of selected muscles and the deep tendon reflexes, a clinician should also know the sensory levels.
Remember:
T4 Nipple line
T7 Xiphoid process
T10 Umbilicus
T12 Groin
Correct Answer: T12
1) T10, T11, and T12
3) L2, L3, and L4
2) L1, L2, and L3
5) L5, S1, and S2
4) L4, L5, and S1
The iliopsoas muscle is the main flexor of the hip, and it receives principal innervation from the L1, L2, and L3 levels. Remember:
L5, S1 and S2 Hip extension: Gluteus maximus muscle
L5, S1, and S2 Foot plantarflexion
L5, S1 and S2 Foot eversion
L4, L5, and S1 Hip abduction: Gluteus medius muscle
L4 and L5 Foot dorsiflexion
L4 and L5 Foot inversion
L2, L3, and L4 Hip adduction
L2, L3, and L4 Knee extension
L1, L2, and L3 Hip flexion: Iliopsoas muscle Correct Answer: L1, L2, and L3
700. (1067) Q2-1374:
Which of the following segmental levels innervates the quadriceps muscle:
1) T10, T11, and T12
3) L2, L3, and L4
2) L1, L2, and L3
5) L5, S1, and S2
4) L4, L5, and S1
The quadriceps muscle is innervated by the femoral nerve from the L2, L3, and L4 segmental levels. Remember:
⢠L5, S1 and S2 Hip extension: Gluteus maximus muscle ⢠L5, S1, and S2 Foot plantarflexion
⢠L5, S1 and S2 Foot eversion
⢠L4, L5, and S1 Hip abduction: Gluteus medius muscle ⢠L4 and L5 Foot dorsiflexion
⢠L4 and L5 Foot inversion ⢠L2, L3, and L4 Hip adduction ⢠L2, L3, and L4 Knee extension
⢠L1, L2, and L3 Hip flexion: Iliopsoas muscle Correct Answer: L2, L3, and L4
1) T12
3) L2
2) L1
5) L4
4) L3
The skin over the thigh is innervated by the L1, L2, and L3 sensory segmental levels. Remember:
L1 Thigh, proximal third, and anterior
L2 Thigh, middle, and anterior
L3 Thigh, distal third, and anterior Correct Answer: L3
702. (1069) Q2-1376:
The skin of the anterior middle third of the thigh is innervated by which of the following sensory segmental levels:
1) T12
3) L2
2) L1
5) L4
4) L3
The skin over the thigh is innervated by the L1, L2, and L3 sensory segmental levels. Remember:
L1 Thigh, proximal third, and anterior
L2 Thigh, middle, and anterior
L3 Thigh, distal third, and anterior Correct Answer: L2
703. (1070) Q2-1377:
The skin of the proximal one-third of the anterior thigh just distal to the inguinal ligament is innervated by which of the following sensory segmental levels:
1) T12
3) L2
2) L1
5) L4
4) L3
The skin over the thigh is innervated by the L1, L2, and L3 sensory segmental levels. Remember:
⢠L1 Thigh, proximal third, and anterior ⢠L2 Thigh, middle, and anterior
⢠L3 Thigh, distal third, and anterior Correct Answer: L1
The tibialis anterior muscle is principally innervated by which of the following segmental levels:
1) L1
3) L3
2) L2
5) L5
4) L4
The tibialis anterior muscle is primarily innervated by the L4 nerve root. The tibialis anterior muscle also receives innervation from L5. Patients with a weak or absent tibialis anterior muscle will have a drop foot or a steppage gait. The tibialis anterior muscle causes dorsiflexion and inversion of the foot and ankle.Correct Answer: L4
(1244) Q2-1614:
The patellar tendon reflex is primarily transmitted through which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
Although the patellar tendon reflex is transmitted primarily through the L4 nerve root, the L2 and L3 nerve roots also contribute to the fibers. A weak reflex is present if the L4 nerve root is completely cut even if there are still fibers of L2 and L3. This reflex is seldom completely absent unless the patient has primary muscle or anterior horn lesions.Correct Answer: L4
(1245) Q2-1615:
The skin on the medial aspect of the leg and great toe is innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
It is important to remember the sensory dermatomes when examining patients. The medial aspect of the leg, foot, and great toe are supplied by the L4 nerve root. The tibial crest separates the L4 and L5 dermatomes on the leg.
Note:
L4 Medial aspect of leg, foot, and great toe
L5 Lateral aspect of the leg and toes two through four S1 Lateral aspect of the fifth toe
Correct Answer: L4
(1246) Q2-1616:
The extensor hallucis longus muscle is innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
The extensor hallucis muscle is primarily innervated by the L5 segmental level. Remember that the L5 nerve root innervates the following muscles:
Extensor hallucis longus
Extensor digitorum longus and brevis Gluteus medius
Correct Answer: L5
(1247) Q2-1617:
The extensor digitorum longus and brevis muscles are primarily innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
The extensor digitorum longus and brevis muscles are primarily innervated by the L5 nerve root. Remember that the L5 nerve root innervates the following muscles:
Extensor hallucis longus
Extensor digitorum longus and brevis Gluteus medius
Correct Answer: L5
(1248) Q2-1618:
The gluteus medius muscle is principally innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
The gluteus medius muscle principally receives innervation from the L5 nerve root through the superior gluteal nerve. Although the principal innervation is from L5, there are contributions from L4 and S1.Correct Answer: L5
(1249) Q2-1619:
Testing for the L5 nerve root can be accomplished through which of the following:
1) Patellar tendon reflex
3) Superficial anal reflex
2) Achilles tendon reflex
5) Beevor's sign
4) Tibialis posterior reflex
There is not a well-defined reflex arc for the L5 nerve root. The tibialis posterior reflex can sometimes be elicited, and this reflex is mediated through the L5 nerve root.
Remember the other reflexes as well:
Patellar tendon L4
Achilles tendon S1
Superficial anal reflex S2, S3, S4
Beevorâs sign refers to asymmetry of the segmental innervation of the rectus abdominus muscles. When a patient performs a sit-up, there is unilateral segmental nerve root loss.Correct Answer: Tibialis posterior reflex
The skin on the lateral aspect of the leg and the dorsum of the foot between the second and fourth toes is innervated by which of the following nerve roots:
1) L1
3) L3
2) L2
5) L5
4) L4
The L5 dermatome covers the skin on the lateral leg and dorsum of the foot from the lateral border of the great toe to the medial border of the little toe.
Note:
L4 Medial aspect of leg, foot, and great toe
L5 Lateral aspect of the leg and toes two through four S1 Lateral aspect of the fifth toe
Correct Answer: L5
712. (1251) Q2-1621:
The peroneus longus and brevis muscles are innervated by which of the following nerve roots:
1) L3
3) L5
2) L4
5) S2
4) S1
The peroneus brevis and longus muscles are principally innervated by the S1 nerve root through the superficial peroneal nerve. Although the innervation is principally S1, the nerve is derived from the L5 and S2 nerve roots, as well.
Remember that the muscles principally innervated by the S1 nerve root are: Peroneus longus and brevis
Gastrocnemius-soleus complex Gluteus maximus
Correct Answer: S1
713. (1252) Q2-1622:
The medial and lateral gastrocnemius muscles principally receive their innervation through which of the following nerve roots:
1) L3
3) L5
2) L4
5) S2
4) S1
The medial and lateral gastrocnemius muscles are principally supplied by the S1 nerve root through the tibial nerve. Although the innervation is principally S1, the nerve is derived from the L5 and S2 nerve roots, as well.
Remember that the muscles principally innervated by the S1 nerve root are: Peroneus longus and brevis
Gastrocnemius-soleus complex Gluteus maximus
Correct Answer: S1
The Achilles tendon reflex (ankle reflex) is transmitted through which of the following nerve roots:
1) L4
3) S1
2) L5
5) S3
4) S2
The Achilles tendon reflex is based upon the triceps muscle group (medial and lateral gastrocnemius muscles and soleus muscle) and is transmitted through the S1 nerve root.
Note the reflexes and the associated nerve roots:
Patellar tendon reflex L4
Posterior tibial reflex L5
Achilles tendon reflex S1 Correct Answer: S1
715. (1254) Q2-1624:
Which of the following groups of nerve roots innervates the intrinsic muscles of the foot:
1) L2, L3, and L4
3) L4, L5, and S1
2) L4 and L5
5) S2 and S3
4) L5, S1, and S2
The intrinsic muscles of the foot are innervated by the S2 and S3 nerve roots. These muscles are difficult to test. Clawing of the toes occurs with intrinsic muscle paralysis.
The following nerve roots innervate important structures: L5, S1, and S2 Hip extension: gluteus maximus
L5, S1, and S2 Foot plantar flexion L5, S1, and S2 Foot eversion
L4, L5, and S1 Hip abduction: gluteus medius L4, L5 Foot dorsiflexion
L4, L5 Foot inversion L2, L3, and L4 Hip adduction L2, L3, and L4 Knee extension
L1, L2, and L3 Hip flexion: iliopsoas Correct Answer: S2 and S3
716. (1255) Q2-1625:
Perianal sensation is derived from which of the following nerve roots:
1) L2, L3, and L4
3) L5, S1, and S2
2) L3, L4, and L5
5) S2, S3, S4, and S5
4) S1, S2, and S3
Perianal sensation is derived from the S2, S3, S4, and S5 nerve roots. The sensory distribution is as follows:
S4-S5 Innermost perianal ring S3 Middle perianal ring
S2 Outermost perianal ring Correct Answer: S2, S3, S4, and S5
717. (1256) Q2-1626:
Which of the following sensory segmental levels corresponds with the nipple line:
1) T2
3) T7
2) T4
5) T12
4) T10
It is important to know the sensory levels to localize pathologic processes. In addition to knowing the innervation of selected muscles and the deep tendon reflexes, the clinician should also know the sensory levels.
Note:
T4 Nipple line
T7 Xiphoid process
T10 Umbilicus
T12 Groin Correct Answer: T4
718. (1257) Q2-1627:
Which of the following segmental nerve levels corresponds to sensation at the xiphoid process:
1) T2
3) T7
2) T4
5) T12
4) T10
The skin over the xiphoid process area is innervated by the T7 nerve root.
It is important to know the sensory levels to localize pathologic processes. In addition to knowing the innervation of selected muscles and the deep tendon reflexes, the clinician should also know the sensory levels.
Note:
T4 Nipple line
T7 Xiphoid process
T10 Umbilicus
T12 Groin Correct Answer: T7
1) T2
3) T7
2) T4
5) T12
4) T10
The skin of the umbilicus is innervated by the T10 level.
It is important to know the sensory levels to localize pathologic processes. In addition to knowing the innervation of selected muscles and the deep tendon reflexes, the clinician should also know the sensory levels.
Note:
T4 Nipple line
T7 Xiphoid process
T10 Umbilicus
T12 Groin Correct Answer: T10
720. (1259) Q2-1629:
The skin over the groin is innervated by which of the following segmental levels:
1) T2
3) T7
2) T4
5) T12
4) T10
The skin over the groin is innervated by the T12 level.
It is important to know the sensory levels to localize pathologic processes. In addition to knowing the innervation of selected muscles and the deep tendon reflexes, the clinician should also know the sensory levels.
Note:
T4 Nipple line
T7 Xiphoid process
T10 Umbilicus
T12 Groin Correct Answer: T12
1) T10, T11, T12
3) L2, L3, L4
2) L1, L2, L3
5) L5, S1, S2
4) L4, L5, S1
The iliopsoas muscle is the main flexor of the hip. The iliopsoas muscle receives innervation from the L1, L2, and L3 levels. One should remember the following nerve roots that innervate important structures:
L5, S1, and S2 Hip extension: gluteus maximus L5, S1, and S2 Foot plantar flexion
L5, S1, and S2 Foot eversion
L4, L5, and S1 Hip abduction: gluteus medius L4, L5 Foot dorsiflexion
L4, L5 Foot inversion L2, L3, and L4 Hip adduction L2, L3, and L4 Knee extension
L1, L2, and L3 Hip flexion: iliopsoas Correct Answer: L1, L2, L3
722. (1261) Q2-1631:
Which of the following segmental levels innervates the quadriceps muscle:
1) T10, T11, T12
3) L2, L3, L4
2) L1, L2, L3
5) L5, S1, S2
4) L4, L5, S1
The quadriceps muscle is innervated by the femoral nerve from the L2, L3, and L4 levels. One should remember the following nerve roots that innervate important structures:
L5, S1, and S2 Hip extension: gluteus maximus L5, S1, and S2 Foot plantar flexion
L5, S1, and S2 Foot eversion
L4, L5, and S1 Hip abduction: gluteus medius L4, L5 Foot dorsiflexion
L4, L5 Foot inversion L2, L3, and L4 Hip adduction L2, L3, and L4 Knee extension
L1, L2, and L3 Hip flexion: iliopsoas Correct Answer: L2, L3, L4
1) T12
3) L2
2) L1
5) L4
4) L3
The skin over the thigh is innervated by L1, L2, and L3. Note:
L1 Thigh, proximal third, anterior L2 Thigh, middle, anterior
L3 Thigh, distal third, anterior Correct Answer: L3
724. (1263) Q2-1633:
The skin of the anterior middle third of the thigh is innervated by which of the following levels:
1) T12
3) L2
2) L1
5) L4
4) L3
The skin over the anterior middle third of the thigh is innervated by L1, L2, and L3. Note:
L1 Thigh, proximal third, anterior L2 Thigh, middle, anterior
L3 Thigh, distal third, anterior Correct Answer: L2
725. (1264) Q2-1634:
The skin of the proximal one-third of the anterior thigh just distal to the inguinal ligament is innervated by which of the following levels:
1) T12
3) L2
2) L1
5) L4
4) L3
The skin of the proximal one-third of the anterior thigh just distal to the inguinal ligament is innervated by L1, L2, and L3. Note:
L1 Thigh, proximal third, anterior L2 Thigh, middle, anterior
L3 Thigh, distal third, anterior Correct Answer: L1
1) Inhibiting of cell wall synthesis
3) Inhibiting RNA synthesis
2) Selectively targeting bacterial topoisomerases (inhibit DNA replication)
5) Poisoning cytochrome C system
4) Inhibiting ribosomal translation
The fluoroquinolone class of antibiotics selectively target bacterial topoisomerases. Topoisomerases maintain the correct amount of supercoiling of DNA in both replicating and nonreplicating areas of the chromosomes.
Fluoroquinolones Second generation
Ciprofloxacin, ofloxacin, and lomefloxacin
Third generation
Sparfloxacin and levofloxacin
Fourth generation
Trovofloxacin, gatifloxacin, and moxifloxacin
Correct Answer: Selectively targeting bacterial topoisomerases (inhibit DNA replication)
727. (1266) Q2-1636:
The fluoroquinolone class of antibiotics, including ofloxacin and ciprofloxacin, is especially useful (considered drug of choice) for osteomyelitis caused by which of the following organisms:
1) Pseudomonas
3) Staphylococcus epidermidis
2) Staphylococcus aureus
5) Streptococcus
4) Enterobacteriaceae
Ofloxacin and ciprofloxacin have been studied in the treatment of post-traumatic osteomyelitis. When compared with parenteral antibiotics, the cure rate was 80% for the fluoroquinolones and 85% for the parenteral antibiotics. The cure rate for the fluoroquinolones was even higher against Enterobacteriaceae. They are considered the drug of choice for osteomyelitis according to the referenced article.Correct Answer: Enterobacteriaceae
adverse effects:
1) Young women
3) Diabetic patients
2) Children
5) Patients with sickle cell anemia
4) Elderly patients
Fluoroquinolones may cause side effects to the musculoskeletal system that include arthralgias, chondrotoxicity, and tendinopathy. Cartilage damage was found in animal studies at therapeutic doses. The cartilage cells of the physeal plate were damaged.
Cartilage blistering, erosions, matrix degeneration, and chondrocyte loss were also present. The fluoroquinolones are not to be used in children, pregnant women, and nursing mothers unless under special circumstances (such as drug resistance in children with cystic fibrosis).
The fluoroquinolones are safe in the other groups of patients. One should remember the following: Light-headedness and dizziness may occur in young women.
Nausea, vomiting, and diarrhea are the most common complications.
Nonsteroidal anti-inflammatory drugs taken in combination will worsen side effects. Photosensitivity may occur.
Achilles tendonitis and rupture may occur.
Correct Answer: Children
729. (1268) Q2-1638:
Which of the following musculoskeletal complications may occur in patients taking fluoroquinolones, such as ciprofloxacin:
1) Osteomalacia
3) Joint laxity
2) Osteoporosis
5) Parethesias
4) Tendon ruptures
Fluoroquinolones may cause side effects to the musculoskeletal system that include arthralgias, chondrotoxicity, and tendinopathy.
Achilles tendonitis and rupture is the most common tendinopathy associated with fluoroquinolone use (usually ciprofloxacin). Fifty percent of cases are bilateral. The interval to rupture is between 2 and 60 days.
Patients at increased risk include:
Patients older than 60 years of age Patients with diabetes
Patients with impaired renal function
Patients who partake in strenuous sports activities Correct Answer: Tendon ruptures
1) Receptor activator of nuclear factor-kappa B (RANK)
3) Bone morphogenetic protein 7
2) Osteoprotegerin
5) Parathyroid hormone related protein (PTHrP)
4) Core binding factor alpha 1 (Cbfa1)
Four proteins that regulate osteoclast activation have been discovered:
Receptor activator of nuclear factor-kappa B (RANK) binds to a receptor on osteoclast precursor cells and positively effects their final differentiation into osteoclasts.
Osteoprotegerin is a soluble decoy receptor that resembles RANK and inhibits osteoclasts.
Tumor necrosis factor-related activation induced cytokine (TRANCE)
Osteoclast differentiation factor
Note:
Core binding factor alpha 1 (Cbfa1) is a transcription factor (coded by the Cbfa1 gene) that is necessary and sufficient for differentiation of cells into osteoblasts and facilitates chondrocyte differentiation during enchondral bone formation.Correct Answer: Receptor activator of nuclear factor-kappa B (RANK)
731. (1270) Q2-1640:
Which of the following proteins negatively effects precursor cells to form osteoclasts:
1) Receptor activator of nuclear factor-kappa B (RANK)
3) Bone morphogenetic protein 7
2) Osteoprotegerin
5) Parathyroid hormone related protein (PTHrP)
4) Core binding factor alpha 1 (Cbfa1)
Four proteins that regulate osteoclast activation have been discovered:
Receptor activator of nuclear factor-kappa B (RANK) binds to a receptor on osteoclast precursor cells and positively effects their final differentiation into osteoclast activation.
Osteoprotegerin is a soluble decoy receptor that resembles RANK and inhibits osteoclasts.
Tumor necrosis factor-related activation induced cytokine (TRANCE)
Osteoclast differentiation factor
Note:
Core binding factor alpha 1 (Cbfa1) is a transcription factor (coded by the Cbfa1 gene) that is necessary and sufficient for differentiation of cells into osteoblasts and facilitates chondrocyte differentiation during enchondral bone formation.Correct Answer: Osteoprotegerin
732. (1271) Q2-1641:
Which of the following proteins or genes is necessary for bone formation and induces osteocalcin (expressed exclusively by osteoblasts):
1) Sox-9 gene
3) Receptor activator of nuclear factor-kappa B (RANK)
2) Core binding factor alpha 1 (Cbfa1)
5) Osteoprotegerin
Tumor necrosis factor-related activation induced cytokine (TRANCE)
Core binding factor alpha 1 (Cbfa1) and its gene (Cbfa1) have been described as anabolic regulators of bone. Cbfa1 is a transcription factor and is responsible for the differentiation of precursor cells into osteoblasts. It also enhances differentiation of chondrocytes during enchondral bone formation. When there is deficiency of Cbfa1 there can be abnormal bone development, as in clediocranial dysplasia.Correct Answer: Core binding factor alpha 1 (Cbfa1)
1) 1,000
3) 10,000
2) 5,000
100,000
4) 30,000
The human genome is composed of approximately 30,000 unique genes. Each gene is composed of a promotor or regulator region and a transcriptional or coding region. Regulatory proteins or transcription factors bind to the promoter region of the gene to signal the beginning of transcription of the DNA into RNA or repress the expression of the gene. The coding region contains both introns and exons. Exon sequences of the gene directly code for the proteins, and the introns are spacers. The intron sequences are enzymatically removed from the newly transcribed messenger RNA by a splicing mechanism.Correct Answer: 30,000
734. (1273) Q2-1643:
Which of the following portions of a gene directly codes for the messenger RNA for eventual translation into proteins on the ribosome:
1) Promoter region
3) Exon
2) Intron
5) Activator or repressor binding site
4) Coding region
The human genome is composed of approximately 30,000 unique genes. Each gene is composed of a promotor or regulator region and a transcriptional or coding region. Regulatory proteins or transcription factors bind to the promoter region of the gene to signal the beginning of transcription of the DNA into RNA or repress the expression of the gene. The coding region contains both introns and exons. Exon sequences of the gene directly code for the proteins, and the introns are spacers. The intron sequences are enzymatically removed from the newly transcribed messenger RNA by a splicing mechanism.Correct Answer: Exon
735. (1910) Q2-2320:
Which of the following occurs in Pagetâs disease:
1) Inadequate mineralization of newly formed bone
3) Normal osteoclastic activity with decreased osteoblastic activity
2) Low bone mass and microarchitectural deterioration of bone
5) Increased osteoclastic activity and increased bone formation
4) Increased osteoclastic activity and normal osteoblastic activity
Pagetâs disease is a remodeling disease in which there is marked bone resorption by the osteoclast. The osteoblasts repair the bone in a mosaic pattern with thickened trabeculae and cement or remodeling lines. There is both increased osteoclastic activity and increased bone formation by the osteoblast.
Inadequate mineralization of newly formed bone is called osteomalacia. In children, there is decreased mineralization at the growth plate.
Osteoporosis refers to low bone mass and microarchitectural deterioration of bone. There are two types of osteoporosis:
High turnover osteoporosis is increased osteoclastic activity and normal osteoblastic activity. In high turnover, the osteoclasts resorb large amounts of bone and the osteoblasts are unable to replace the bone. One finds markers for high levels of bone resorption and bone formation in the serum and the urine.
Low turnover osteoporosis is normal osteoclastic activity with decreased osteoblastic activity. In low turnover, the osteoclastic activity is at the normal rate; however, there is insufficient osteoblastic activity to fill in the osteoclastic resorption cavities. The markers for osteoclastic resorption are normal and the markers for bone formation are decreased.
Correct Answer: Increased osteoclastic activity and increased bone formation
1) Serum alkaline phosphatase
3) Gamma-glutamyl transpeptidase
2) Aspartate aminotransferase and alanine aminotransferase
5) Urine N-telopeptide, pyridinoline, and deoxypyridinoline
4) Osteocalcin
Bone resorption is assessed by measuring the products of bone remodeling. N-telopeptide, pyridinoline, and deoxypyridinoline are collagen cross-link products that are released during bone turnover. These collagen cross-links can be measured in the urine. A new marker can be measured in the serum and is called carboxy terminal collagen cross-links (CrossLaps).
Bone formation is assessed with serum alkaline phosphastase and osteocalcin.
Liver function tests include aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transpeptidase.Correct Answer: Urine N-telopeptide, pyridinoline, and deoxypyridinoline
737. (1912) Q2-2322:
Pagetâs disease is common in all of the following bones except:
1) Humerus
3) Femur
2) Spine
5) Pelvis
4) Hands and feet
Key features of Pagetâs disease:
Remodeling disease caused by excessive osteoclastic activity
Rarely diagnosed in patients younger than 40 years of age; most patients diagnosed after age 50 Most common sites include pelvis, femur, spine, skull, and tibia
Less common sites include clavicles, scapulae, ribs, and facial bones Rarely found in the hands and feet
Pagetic bone
is more susceptible to fracture is less compact
is more vascular
tends to bow in weight bearing areas
Geographic clustering (up to 4% in patients older than 55 years of age) England
Northern Europe North America
Australia, New Zealand
Rare in Asia, China, Indonesia, Malaysia, and sub-Saharan Africa Possibly a slow viral disease
RNA paramyxovirus (e.g., respiratory syncytial virus and measles) Correct Answer: Hands and feet
1) England
3) Northern Europe
2) United States
5) Sub-Saharan Africa
4) Australia
Key features of Pagetâs disease
Remodeling disease caused by excessive osteoclastic activity
Rarely diagnosed in patients younger than 40 years of age; most patients diagnosed after age 50 Most common sites include pelvis, femur, spine, skull, and tibia
Less common sites include clavicles, scapulae, ribs, and facial bones Rarely found in the hands and feet
Pagetic bone
is more susceptible to fracture is less compact
is more vascular
tends to bow in weight bearing areas
Geographic clustering (up to 4% in patients older than 55 years of age) England
Northern Europe North America
Australia, New Zealand
Rare in Asia, China, Indonesia, Malaysia, and sub-Saharan Africa Possibly a slow viral disease
RNA paramyxovirus (e.g., respiratory syncytial virus and measles) Correct Answer: Sub-Saharan Africa
739. (1914) Q2-2324:
Which of the following occurs in active Pagetâs disease:
1) Intense osteoclastic activity, intense osteoblastic activity
3) Intense osteoclastic activity, decreased osteoblastic activity
2) Decreased osteoclastic activity, decreased osteoblastic activity
5) Intense osteoclastic activity, normal osteoblastic activity
4) Decreased osteoclastic activity, increased osteoblastic activity
Marked bone resorption by the osteoclast and marked bone formation by the osteoblast occurs in active Pagetâs disease. The activities of the osteoclast and osteoblast are linked together.Correct Answer: Intense osteoclastic activity, intense osteoblastic activity
740. (1915) Q2-2325:
Osteocytic osteolysis refers to which of the following processes:
1) Loss of bone through decreased bone formation
3) Removal of bone by osteoclasts
2) Mobilization of poorly crystallized calcium salts without effect on bone matrix
5) Osteocyte-mediated resorption of bone matrix
4) Loss of bone by osteoclasts in multiple myeloma
Osteocytes do not directly resorb bone. Osteocytes have receptors for parathyroid hormone, and they mobilize poorly crystallized calcium salts that surround them without resorbing the bone matrix. The osteocytes connect with each other through long, thin cytoplasmic processes.Correct Answer: Mobilization of poorly crystallized calcium salts without effect on bone matrix
areas of maximum stress and strain:
1) Mast cells in bone marrow
3) Plasma cells
2) Osteoblasts
5) Osteocytes
4) Osteoclasts
Osteocytes respond to mechanical signals and transmit messages to other cells to increase bone remodeling.Correct Answer: Osteocytes
742. (1917) Q2-2327:
Receptor activator of nuclear factor âkB (RANK) is located on which of the following cells:
1) Osteoblasts
3) Osteocytes
2) Plasma cells
5) Osteoclast precursors
4) Active osteoclasts
The activation of osteoclasts is a complex process. Surface receptors on the osteoclast precursor cells are called RANK. Receptor activator of nuclear factor âkB ligand (RANKL) is expressed on the surface of osteoblasts/stromal cells. The RANKL proteins leave the osteoblast and attach to the RANK receptor on the osteoclast precursor. Macrophage colony stimulating factor then facilitates the production of active osteoclasts from the osteoclast precursor.
Osteoprotegerin (OPG) is an inhibitor that is produced on the cell surface of hematopoietic precursor cells and mature osteoclasts. OPG binds to RANK receptor to inhibit the activation of osteoclasts
RANKL
OPG
Stimulates osteoclast differentiation and osteoclast activity Inhibits osteoclast apoptosis
Induces hypercalcemia when injected Loss of expression induces:
Osteopetrosis
Tooth eruption defects
T and B cell differentiation defects
Soluble decoy receptor for RANKL Blocks osteoclast formation Reduces hypercalcemia
Overexpression induces osteopetrosis Loss of expression induces osteoporosis Prevents calcification of large arteries
Correct Answer: Osteoclast precursors
1) Inhibits osteoclast apoptosis
3) Activates osteoclast precursors
2) Inhibits osteoclast formation
5) Binds to receptor activator of nuclear factor âkB ligand (RANKL)
4) Induces hypercalcemia
The activation of osteoclasts is a complex process. Surface receptors on the osteoclast precursor cells are called RANK. Receptor activator of nuclear factor âkB ligand (RANKL) is expressed on the surface of osteoblasts/stromal cells. The RANKL proteins leave the osteoblast and attach to the RANK receptor on the osteoclast precursor. Macrophage colony stimulating factor then facilitates the production of active osteoclasts from the osteoclast precursor.
Osteoprotegerin (OPG) is an inhibitor that is produced on the cell surface of hematopoietic precursor cells and mature osteoclasts. OPG binds to RANK receptor to inhibit the activation of osteoclasts.
OPG
Soluble decoy receptor for RANKL Blocks osteoclast formation Reduces hypercalcemia
Overexpression induces osteopetrosis Loss of expression induces osteoporosis Prevents calcification of large arteries
Correct Answer: Inhibits osteoclast formation
744. (1919) Q2-2329:
Which of the following proteins or hormones assists in the transport of calcium in the kidney against chemical and electrical gradients:
1) Calcitonin
3) Osteoprotegerin
2) Calbindin
5) Vitamin D3
4) Parathyroid hormone
Calbindin, a vitamin D dependent and calcium binding protein, assists in the transport of calcium against chemical and electrical gradients. Most regulation calcium resorption in the kidney occurs in the distal convoluted segment.Correct Answer: Calbindin
745. (1920) Q2-2330:
Which of the following is the rate-limiting step in the production of biologically active Vitamin D:
1) 25 hydroxylation in the liver
3) Conversion of 7 dehydrocholesterol to vitamin D3 in the skin
2) Absorption of calcium in the duodenum
5) Absorption of calcium in the jejunum
4) 1 hydroxylation in the kidney
The addition of a second hydroxyl group at the 1 position to 25 hydroxy vitamin D3 is the rate-limiting step in the formation of the active from of vitamin D3. Impaired renal function is common in older individuals.Correct Answer: 1 hydroxylation in the kidney
produced by osteoblasts:
1) Parathyroid hormone
3) Thyroid hormone
2) 25 hydroxyvitamin D3
5) Calcitonin
4) 1,25 dihydroxyvitamin D3
The active from of vitamin D (1,25 dihydroxyvitamin D3) regulates the control of RANKL production by the osteoblast.
The activation of osteoclasts is a complex process. Surface receptors on the osteoclast precursor cells are called RANK. Receptor activator of nuclear factor âkB ligand (RANKL) is expressed on the surface of osteoblasts/stromal cells. The RANKL proteins leave the osteoblast and attach to the RANK receptor on the osteoclast precursor. Macrophage colony stimulating factor then facilitates the production of active osteoclasts from the osteoclast precursor.Correct Answer: 1,25 dihydroxyvitamin D3
747. (1922) Q2-2332:
Which of the following proteins or vitamins influences growth plate chondrocyte maturation as a potent mitogen in the proliferative zone:
1) 1,25 dihydroxyvitamin D3
3) Insulin
2) 24,25 dihydroxyvitamin D3
5) Calcitonin
4) 1 hydroxyvitamin D3
Traditionally, 24,25 dihydroxyvitamin D3 was considered an inactive form of vitamin D. Recent studies suggest that 24,25 dihydroxyvitamin D3 influences growth plate chondrocyte maturation as a potent mitogen in the proliferative zone and may also contribute to bone formation and fracture repair.Correct Answer: 24,25 dihydroxyvitamin D3
748. (1923) Q2-2333:
Which of the following cells has receptors for parathyroid hormone:
1) Osteocytes
3) Plasma cells
2) Osteoclasts
5) Osteoclast precursor cells
4) Osteoblasts
Osteoblasts have receptors for parathyroid hormone. Once stimulated, the cells release interleukin-6 (IL-6). IL-6 signals osteoclasts to resorb bone. The osteoblasts secrete neutral proteases that degrade the osteoid surface. Osteoclasts then attach to the bone surface and secrete acid proteases that degrade the bone matrix. Parathyroid hormone related protein increases osteoblast expression of receptor activator of nuclear factor âkB ligand (RANKL). RANKL binds to osteoclast precursor cells for the formation of active osteoclasts.Correct Answer: Osteoblasts
749. (1924) Q2-2334:
Parathyroid hormone stimulates which of the following cells to secrete neutral protease that degrades the osteoid bone surface:
1) Osteoblasts
3) Osteoclasts
2) Mast cells
5) Osteoclast precursor cells
4) Osteocytes
Osteoblasts have receptors for parathyroid hormone. Osteoblasts have neutral proteases that begin the degradation of the osteoid matrix. Once stimulated, the cells release interleukin-6 (IL-6). IL-6 signals osteoclasts to resorb bone. The osteoblasts secrete neutral proteases that degrade the osteoid surface. Osteoclasts then attach to the bone surface and secrete acid proteases that degrade the bone matrix. Parathyroid hormone related protein increases osteoblast expression of receptor activator of nuclear factor âkB ligand (RANKL). RANKL binds to osteoclast precursor cells for the formation of active osteoclasts.Correct Answer: Osteoblasts
1) Osteoprotegerin
3) Interleukin-6
2) 1,25 dihydroxyvitamin D3 production
5) Receptor activator of nuclear factor âkB ligand (RANKL)
4) Kidney 1 alpha-hydroxylase
Parathyroid hormone inhibits the production of osteoprotegerin. Osteoprotegerin is a decoy inhibitor of the receptor activator of nuclear factor âkB. Osteoprotegerin inhibits osteoclast activation.Correct Answer: Osteoprotegerin
751. (1926) Q2-2336:
Osteoclasts have receptors for which of the following:
1) 1,25 dihydroxyvitamin D3
3) Osteoprotegerin
2) Parathyroid hormone
5) Calcitonin
4) Receptor activator of nuclear factor âkB
Osteoclasts have receptors for calcitonin. Calcitonin causes osteoclasts to shrink in size and reduces their ability to resorb bone.Correct Answer: Calcitonin
752. (1927) Q2-2337:
After oophorectomy or menopause, bone loss per year is estimated to be:
1) 0.3% to 0.5%
3) 5% to 10%
2) 2% to 3%
5) 15% to 20%
4) 10% to 15%
The normal estimated age-related bone loss per year is 0.5%. After oophorectomy or during the first 6 to 8 years after menopause, bone loss can be as high as 2.0% to 3.0% per year.Correct Answer: 2% to 3%
753. (1928) Q2-2338:
Estrogen deficiency results in which of the following:
1) Increased interleukin-6 (IL-6) expression
3) Decreased IL-6 expression
2) Increased osteoprotegerin (OPG) expression
5) Decreased macrophage colony-stimulating factor (M-CSF) expression
4) Decreased receptor activator of nuclear factor âkB ligand (RANKL)
Estrogen deficiency results in increased bone resorption. An increase in IL-6 expression stimulates osteoclasts to resorb bone.
An increase in M-CSF and RANKL results in increased osteoclastic activity. OPG decreases osteoclastic activity as a decoy inhibitor of RANK.Correct Answer: Increased interleukin-6 (IL-6) expression
1) Osteoclasts
3) Osteoblasts
2) Osteoclast precursor cells
5) Mast cells
4) Osteocytes
Osteoblasts have receptors for androgens. Although androgens prevent bone resorption and may increase bone mass, the process is not understood at this time.Correct Answer: Osteoblasts
755. (1930) Q2-2340:
Corticosteroids decrease bone mass through which of the following mechanisms:
1) Inhibiting calcium absorption in the intestines
3) Increasing calcium binding proteins
2) Decreasing calcium excretion in the kidneys
5) Increasing bone resorption at high doses
4) Increasing overall protein synthesis
Corticosteroids decrease overall protein synthesis. In the intestines, corticosteroids decrease calcium-binding proteins, hence decreasing the absorption of calcium.
Corticosteroids:
Decrease overall protein synthesis Increase calcium excretion in the kidney
Inhibit bone formation and absorption at high doses
With the above changes, a state of secondary hyperparathyroidism exists. Correct Answer: Inhibiting calcium absorption in the intestines
756. (1931) Q2-2341:
Which of the following defines osteoporosis according to the World Health Organization:
1) 0.5 to 1.0 standard deviation (SD) below age-matched controls
3) 1.0 to 2.5 SD below age-matched controls
2) 1.0 to 2.0 SD below age-matched controls
5) 2.5 to 5.0 SD below age-matched controls
4) More than 2.5 SD below age-matched controls
Osteoporosis is a condition in which there is a deficiency of bone mass and microarchitectural deterioration of bone tissue. Osteoporosis is defined as a bone mass that is more than 2.5 SD below the mean for age-matched controls. Patients are considered osteopenic with mild to moderate bone deficiency with a bone density of 1.0 to 2.5 SD.Correct Answer: More than 2.5 SD below age-matched controls
1) Primarily occurs in patients older than 75 years of age
3) Cortical and trabecular bone are affected
2) Female to male ratio is 2:1
5) Related to estrogen deficiency rather than calcium intake
4) Low turnover osteoporosis
Type 1 osteoporosis is the most common form of osteoporosis and is found in women during postmenopausal years. Type 1 osteoporosis is related to estrogen deficiency rather than a problem in calcium intake or absorption.
Features of type 1 osteoporosis include: Female to male ratio is 6:1
High turnover osteoporosis
Bone loss rate of 2% to 3% per year for 6 to 10 years following menopause Trabecular bone is most affected
Related to estrogen deficiency rather than calcium intake
Correct Answer: Related to estrogen deficiency rather than calcium intake
758. (1933) Q2-2343:
Which of the following features is associated with type 2 osteoporosis:
1) High turnover osteoporosis
3) Loss of cortical and trabecular bone
2) Female to male ratio is 6:1
5) Greatest bone loss in the first 6 to 10 years following menopause
4) Related to estrogen deficiency
Type 1 osteoporosis is the most common form of osteoporosis and is found in women during postmenopausal years. Type 1 osteoporosis is related to estrogen deficiency rather than a problem in calcium intake or absorption.
Features of type 1 osteoporosis include: Female to male ratio is 6:1
High turnover osteoporosis
Bone loss rate of 2% to 3% per year for 6 to 10 years following menopause Trabecular bone is most affected
Related to estrogen deficiency rather than calcium intake
Type 2 osteoporosis, also called senile or involutional osteoporosis, is a low turnover osteoporosis and principally occurs in patients older than 75 years of age.
Features of type 2 osteoporosis include:
Female to male ratio is 2:1 Patients older than 75 years of age Low turnover osteoporosis
Trabecular and cortical bone affected Associated with hip fractures
Related to a lifelong deficiency of calcium Correct Answer: Loss of cortical and trabecular bone
1) Osteoblasts have estrogen receptors.
3) Estrogen decreases osteoclast activity.
2) Estrogen modulates calcium absorption and renal excretion.
5) The protective effect of estrogren therapy continues to prevent bone loss after therapy is discontinued.
4) Estrogen prevents osteoporosis in 80% of postmenopausal women.
Estrogen therapy is one of the main therapeutic interventions used to prevent osteoporosis in postmenopausal women. Features of estrogen interactions include:
Osteoblasts have estrogen receptors.
Estrogen indirectly affects calcium metabolism by modulating calcium absorption and renal excretion. Estrogen decreases osteoclast activity.
Estrogen prevents osteoporosis in 80% of postmenopausal women.
The protective effect of estrogren therapy ends when therapy is discontinued.
Correct Answer: The protective effect of estrogren therapy continues to prevent bone loss after therapy is discontinued.
760. (1935) Q2-2345:
Which of the following drugs is a selective estrogen receptor modulator:
1) Fosamax (alendronate sodium tablets, Merck & Co., Inc.)
3) Aredia (pamidronate disodium for injection, Novartis Pharmaceuticals Corporation)
2) Progestin
5) Alendronate sodium
4) Evista (raloxifene, Eli Lilly and Company)
A new class of selective estrogen receptor modulator acts as an antagonist in breast tissue and an agonist in bone. Raloxifene selectively stimulates estrogen receptors in bone and is an antagonist in breast tissue.
Progestin used in conjunction with estrogen opposes the action of estrogen and lowers the risk of endometrial cancer that might occur with estrogen therapy alone.
Aredia, Fosamax, and alendronate are biphosphonates that inhibit osteoclasts, thereby decreasing bone resorption.Correct Answer: Evista (raloxifene, Eli Lilly and Company)
761. (1936) Q2-2346:
Which of the following mechanisms of bisphosphonate action occurs when a bisphosphonate is used to treat osteoporosis:
1) Increasing calcium absorption in the intestines
3) Stimulating osteoblast precursors
2) Decreasing urinary excretion of calcium
5) Increasing phosphate reabsorption in the kidney
4) Binding to hydroxyapatite crystals
Bisphosphonates are effective in the treatment of osteoporosis because they bind to the hydroxyapatite crystals and inhibit crystal resorption.
Other effects of bisphosphonates include:
Reducing production of proteins and lysosomal enzymes by osteoclasts Reducing the formation of new bone remodeling units
Inducing osteoclast cell death
Reducing the formation of new osteoclasts
After 1 year of treatment, alendronate decreases fracture rates (hip, spine, and wrist) by 50%. Bone mass gains are modest â 2% to 4% per year in the vertebra and 1% to 2% per year in the hip.Correct Answer: Binding to hydroxyapatite crystals
1) Pruritus
3) Peripheral edema
2) Dizziness
5) Light sensitivity
4) Esophagitis and dyspepsia
The most significant side effect of biphosphonates is esophagitis and dyspepsia. Biphosphonates must be taken on an empty stomach with no oral intake for 30 minutes. In addition, patients should remain upright.Correct Answer: Esophagitis and dyspepsia
763. (1938) Q2-2348:
Which of the following conditions is characterized by decreased osteoclastic resorption of bone and cartilage with normal bone formation:
1) Type 1 osteoporosis
3) Osteopetrosis
2) Type 2 osteoporosis
5) Secondary hyperparathyroidism
4) Pagetâs disease
Osteopetrosis is a rare disorder in which there is decreased osteoclastic resorption of bone and cartilage with normal bone formation. There are a number of different forms of the condition.
The most common form of osteopetrosis is an autosomal dominant type with mild features (adult or tarda). Patients may have mild anemia, have one or more fractures, or be asymptomatic.
The juvenile form of osteopetrosis is a severe autosomal disorder. Children have multiple fractures, severe anemia, thrombocytopenia, and hepatosplenomegaly. Effected children are also immunocompromised.Correct Answer: Osteopetrosis
764. (1939) Q2-2349:
Which of the following is an effective medication for osteopetrosis:
1) Calcitonin
3) Fosamax (alendronate sodium tablets, Merck & Co., Inc.)
2) Alendronate
5) Interferon gamma-1
4) Calcium carbonate
Interferon gamma-1 is the only treatment for osteopetrosis that is approved by the Food and Drug Administration.Correct Answer: Interferon gamma-1
1) Cancellous bone, methylmethacrylate, cortical bone, titanium, and cobalt chrome
3) Methylmethacrylate, cancellous bone, titanium, cortical bone, and cobalt chrome
2) Cancellous bone, cortical bone, titanium, methylmethacrylate, and cobalt chrome
5) Titanium, cobalt chrome, methylmethacrylate, cancellous bone, and cortical bone
4) Titanium, cancellous bone, methylmethacrylate, cortical bone, and cobalt chrome
The proper sequence when listing common orthopedic biomaterials in order of increasing modulus is: Elastic Modulus
Cancellous bone Polyethylene Methylmethacrylate Cortical bone Titanium alloy Stainless steel Cobalt chrome
Correct Answer: Cancellous bone, methylmethacrylate, cortical bone, titanium, and cobalt chrome
766. (2329) Q2-2784:
Which of the following areas results in latitudinal physeal enlargement:
1) Proliferative zone
3) Reserve zone
2) Provisional calcification zone
5) Perichondrial ring of La Croix
4) Hypertrophic zone
The perichondrial ring of La Croix is the source of cells which differentiate into chondrocytes and results in latitudinal physeal enlargement.
The other answers refer to specific growth plate zones which have functions. The reserve zone is for matrix production and storage. The proliferative zone is for matrix production and cellular proliferation. The hypertrophic zone contains the zone of maturation, degeneration, and provisional calcification.
Correct Answer: Perichondrial ring of La Croix
767. (2330) Q2-2785:
The abrupt appearance of which of the following collagens heralds the onset of ossification in the physis:
1) Type I
3) Type X
2) Type VI
5) Type IX
4) Type II
The terminal hypertrophic chondrocytes in the hypertrophic zone produce Type X collagen. The appearance of Type X collagen heralds ossification. Remember that Type II collagen is the most abundant collagen in the hypertrophic zone.Correct Answer: Type X
Which of the following zones of the physis is involved in Salter Harris Type I and II fractures:
1) Proliferative zone
3) Reserve zone
2) Perichondrial ring
5) Zone of provisional calcification
4) Node of Ranvier
Salter Harris Type I and II fractures occur through the zone of provisional calcification or through the hypertrophic zone. The reserve and proliferative zone remain intact and growth can proceed normal after healing of the fracture.Correct Answer: Zone of provisional calcification
769. (2332) Q2-2787:
Which of the following is the most likely origin for the greater medullary artery:
1) Lower cervical segmental
3) Upper lumbar segmental
2) Middle thoracic segmental
5) Lower thoracic segmental
4) Upper thoracic segmental
The major part of the blood supply of the spinal cord is provided by the medullary or radicular arteries. The only feeder for the lower thoracic spinal cord is the greater medullary artery or artery of Adamkiwicz (T9-T11). One should remember that in the spine, the right-sided approach is preferred to avoid the aorta and segmental artery of Adamkiwicz.Correct Answer: Lower thoracic segmental
770. (2333) Q2-2788:
Enchondral ossification is responsible for mineralization in all of the following conditions except:
1) Heterotopic bone formation
3) Callus formation during fracture healing
2) Embryonic long bone development
5) Perichondrial bone formation
4) Cartilage degeneration in osteoarthritis
Enchondral bone formation or ossification is bone formation on a cartilage model. Enchondral bone formation occurs in embryonic long bone development, epiphyseal secondary center of ossification formation, callus formation during fracture healing, degenerating cartilage of osteoarthritis, calcifying cartilage tumors, and bone formed with use of demineralized bone matrix.
Intramembranous bone formation occurs in flat bone development (pelvis, clavicle, skull bones), bone formation during distraction osteogenesis, and perichondrial bone formation.Correct Answer: Perichondrial bone formation
771. (2334) Q2-2790:
Which of the following is true concerning cancellous bone:
1) It remodels through surface cells
3) It has high density
2) It has low surface area
5) It has a low metabolic rate and turnover
4) It is organized in osteons and lamellae
Cortical bone has a much greater density than cancellous bone. Therefore, it is stiffer and stronger. Cortical bone has a higher density than cancellous bone, is organized into osteons and lamellae, has low surface area, lower metabolic rate than cancellous bone, remodels through osteons, and accounts for much of the structural strength of bones.
Cancellous bone has a lower density than cortical bone, has an organization of lamellar bone, has a high surface area, higher metabolic rate than cortical bone, remodels through surface cells, and transmits forces in subchondral location.
Correct Answer: It remodels through surface cells
Which of the following statements is true regarding metaphyseal cortical bone formation in a child with open physes:
1) Cortical bone is formed by intramembranous bone formation.
3) Cortical bone is formed by coalescence of enchondral trabecular bone.
2) Cortical bone is formed by intramembranous and enchondral bone formation.
5) Cortical bone is formed from the groove of Ranvier.
4) Cortical bone is solely formed from the periosteal bone.
Cadet and colleagues studied the formation of cortical bone in the metaphyses of rabbits. They found that the metaphyseal cortical bone is formed by coalescence of enchondral trabecular bone.
Important points from this study include:
Metaphyseal cortical bone is formed by coalescence of enchondral trabecular bone. The coalescence is formed by an increased osteoblast surface.
The increased osteoblast surface is likely caused by factors from the periosteum.
The bone that is produced by the cells in the groove of Ranvier probably does not contribute to the metaphyseal cortical bone.
Correct Answer: Cortical bone is formed by coalescence of enchondral trabecular bone.
773. (2450) Q2-2915:
Which of the following molecules influences embryonic bone formation and fracture healing:
1) Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1)
3) Platelet derived growth factor (PDGF)
2) Transforming growth factor-beta (TGF-B)
5) Vascular endothelial growth factor (VEGF)
4) Interleukin-1 (IL-1)
Important concepts to remember regarding signaling proteins include:
Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1) influence embryonic bone formation and fracture healing. Vascular endothelial growth factor (VEGF) plays a role in cartilage hypertrophy at the growth plate and during fracture healing.
Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF) are found in early fracture hematoma, and these factors modulate cell proliferation and differentiation.
Bone morphogenetic protein and interleukin 1 and 6 are expressed during cartilage formation.
Correct Answer: Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1)
774. (2451) Q2-2916:
Which of the following molecules are present in a hematoma after a fracture and aid in modulating cell proliferation and differentiation:
1) Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1)
3) Interleukin-1 (IL-1)
2) Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF)
5) Vascular endothelial growth factor (VEGF)
4) Interleukin-6 (IL-6)
Important concepts to remember regarding signaling proteins include:
Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1) influence embryonic bone formation and fracture healing. Vascular endothelial growth factor (VEGF) plays a role in cartilage hypertrophy at the growth plate and during fracture healing.
Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF) are found in early fracture hematoma, and these factors modulate cell proliferation and differentiation.
Bone morphogenetic protein and interleukin 1 and 6 are expressed during cartilage formation. Correct Answer: Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF)
Which of the following molecules play an important role in cartilage hypertrophy during growth plate development and ossification in fracture healing:
1) Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1)
3) Interleukin-1 (IL-1)
2) Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF)
5) Vascular endothelial growth factor (VEGF)
4) Interleukin-6 (IL-6)
Important concepts to remember regarding signaling proteins include:
Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1) influence embryonic bone formation and fracture healing. Vascular endothelial growth factor (VEGF) plays a role in cartilage hypertrophy at the growth plate and during fracture healing.
Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF) are found in early fracture hematoma, and these factors modulate cell proliferation and differentiation.
Bone morphogenetic protein and interleukin 1 and 6 are expressed during cartilage formation.
Correct Answer: Vascular endothelial growth factor (VEGF)
776. (2453) Q2-2918:
All of the following factors are important to achieve primary osteonal healing during plate fixation except:
1) Anatomic reduction
3) Adequate vascular supply
2) Rigid fixation
5) Very low strain levels
4) Moderate-to-high strain levels
In primary osteonal bone healing, osteoclasts cut channels across the bone contact sites and blood vessels, and osteoblasts fill in the gap with new bone.
To achieve osteonal healing, there must be an anatomic reduction with rigid fixation, an adequate blood supply, and the amount of motion at the fracture site must be very small to none (very low strain levels).
Moderate-to-high strain levels occur if there is motion at the osteosynthesis site. This motion results from poor fixation (lack of rigidity) or excessive loading during the healing period. High strain levels in the gap favor the formation of granulation tissue rather than bone.
Correct Answer: Moderate-to-high strain levels
777. (2454) Q2-2919:
All of the following factors increase the rigidity of an external fixator except:
1) Increased individual pin diameter
3) Increased bone-to-rod distance
2) Increased pin number
5) Separating half pins by 45°
4) Increased pin group separation
There are many factors that increase the rigidity of an external fixator, including: Increased pin diameter
Increased pin number Decreased bone-to-rod distance Increased pin group separation Separating half pins by 45°
Increasing the bone-to-rod distance decreases the rigidity of the system. The fracture gap is also important. The fracture gap should be minimized for excellent bone apposition.
Correct Answer: Increased bone-to-rod distance
Which of the following graft types has both osteoinductive and osteoconductive properties:
1) Autogenous bone marrow
3) Bone morphogenetic protein-2 (BMP-2)
2) Coral-based hydroxyapatite bone graft substitute
5) Cancellous bone graft
4) Recombinant bone morphogenetic protein-7 (rhBMP-7)
Grafting materials may include osteoconductive and/or osteoinductive properties and osteoprogenitor cells.
Cancellous bone and vascularized bone graft are the only materials that have significant osteoconductive, osteoinductive, and osteoprogenitor cells.
Several materials are mainly osteoinductive. Remember the definition of osteoinductive and osteoconductive properties:
Osteoinductive factors: Molecules that have the capability of inducing osteoblastic precursors to differentiate into mature bone forming cells.
Osteoinductive factors (without significant osteoconductive properties) include growth factors such as BMP-2 and rhBMP-7 (OP-1, Stryker Biotech, Hopkinton, Mass) and demineralized bone matrix.
Osteoconductive factors: The ability of a porous material to provide a scaffold for new bone formation.
Osteoconductive materials (without significant osteoinductive properties) include ceramics such as coral-based hydroxyapatite graft substitutes, Norian skeletal repair system (Norian Corporation, Cupertino, Calif), and calcium sulfate pellets (Osteoset, Wright Medical Technology Inc., Arlington, Tenn).
Bone marrow has the potential of supplying osteoprogenitor cells but has little osteoinductive or osteoconductive properties. Correct Answer: Cancellous bone graft
779. (2456) Q2-2921:
Which of the following materials has mainly osteoconductive properties with little or no osteoinductive ability:
1) Autogenous bone marrow
3) Bone morphogenetic protein-2 (BMP-2)
2) Coral-based hydroxyapatite bone graft substitute
5) Cancellous bone graft
4) Recombinant bone morphogenetic protein-7 (rhBMP-7)
Grafting materials may include osteoconductive and/or osteoinductive properties and osteoprogenitor cells.
Cancellous bone and vascularized bone graft are the only materials that have significant osteoconductive, osteoinductive, and osteoprogenitor cells.
Several materials are mainly osteoinductive. Remember the definition of osteoinductive and osteoconductive properties:
Osteoinductive factors: Molecules that have the capability of inducing osteoblastic precursors to differentiate into mature bone forming cells.
Osteoinductive factors (without significant osteoconductive properties) include growth factors such as BMP-2 and rhBMP-7 (OP-1, Stryker Biotech, Hopkinton, Mass) and demineralized bone matrix.
Osteoconductive factors: The ability of a porous material to provide a scaffold for new bone formation.
Osteoconductive materials (without significant osteoinductive properties) include ceramics such as coral-based hydroxyapatite graft substitutes, Norian skeletal repair system (Norian Corporation, Cupertino, Calif), and calcium sulfate pellets (Osteoset, Wright Medical Technology Inc., Arlington, Tenn).
Bone marrow has the potential of supplying osteoprogenitor cells but has little osteoinductive or osteoconductive properties. Correct Answer: Coral-based hydroxyapatite bone graft substitute
Which of the following materials has mainly osteoinductive properties with little or no osteoconductive ability:
1) Autogenous bone marrow
3) Calcium sulfate crystals
2) Coral-based hydroxyapatite bone graft substitute
5) Cancellous bone graft
4) Recombinant bone morphogenetic protein-7 (rhBMP-7)
Grafting materials may include osteoconductive and/or osteoinductive properties and osteoprogenitor cells.
Cancellous bone and vascularized bone graft are the only materials that have significant osteoconductive, osteoinductive, and osteoprogenitor cells.
Several materials are mainly osteoinductive. Remember the definition of osteoinductive and osteoconductive properties:
Osteoinductive factors: Molecules that have the capability of inducing osteoblastic precursors to differentiate into mature bone forming cells.
Osteoinductive factors (without significant osteoconductive properties) include growth factors such as BMP-2 and rhBMP-7 (OP-1, Stryker Biotech, Hopkinton, Mass) and demineralized bone matrix.
Osteoconductive factors: The ability of a porous material to provide a scaffold for new bone formation.
Osteoconductive materials (without significant osteoinductive properties) include ceramics such as coral-based hydroxyapatite graft substitutes, Norian skeletal repair system (Norian Corporation, Cupertino, Calif), and calcium sulfate pellets (Osteoset, Wright Medical Technology Inc., Arlington, Tenn).
Bone marrow has the potential of supplying osteoprogenitor cells but has little osteoinductive or osteoconductive properties. Correct Answer: Recombinant bone morphogenetic protein-7 (rhBMP-7)
Slide 1 Slide 2 Slide 3
A 65-year-old man has severe foot pain. His plain radiograph is shown in Slide 1, and a needle biopsy specimen in Slides and 3. The most likely diagnosis is:
1) Coccidioidomycosis
3) Rheumatoid arthritis
2) Pigmented villonodular synovitis
5) Tuberculosus
4) Gout
Gout is caused by the deposition of monosodium urate crystals in tissues, typically around joints. Common locations of gout include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first affected location is the great toe. Gout commonly occurs inside a joint for two reasons - synovial fluid is a poorer solvent than plasma and lower temperatures (as in peripheral joints) favor crystallization.
Neutrophils ingest the crystals and release potent lysosomal enzymes. Punched lesions may be seen on radiographs in chronic cases, and one can often see an overlying lip of cortex at the edge of the lesion.
Histologically, the tophi have several features:
Acellular amorphous material Macrophages
Foreign body giant cells
In this patient, the joint space is preserved on the plain radiographs. The biopsy specimen has the characteristic features of gout -acellular amorphous material, macrophages, and foreign body giant cells.
Correct Answer: Gout
Slide 1 Slide 2 Slide 3
A 65-year-old man has severe foot pain. His plain radiograph is shown in Slide 1, and a needle biopsy specimen in Slides 2 and
3. The most appropriate treatment for this patient is:
1) Irrigation/debridement followed by antibiotics
3) Diphosphonate therapy
2) Chemotherapy followed by wide resection
5) Arthroscopic debridement
4) Nonsteriodal anti-inflammatory agents
Gout is caused by the deposition of monosodium urate crystals in tissues, typically around joints. Common locations of gout include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first affected location is the great toe. Gout commonly occurs inside a joint for two reasons - synovial fluid is a poorer solvent than plasma and lower temperatures (as in peripheral joints) favor crystallization.
Neutrophils ingest the crystals and release potent lysosomal enzymes. Punched lesions may be seen on radiographs in chronic cases, and one can often see an overlying lip of cortex at the edge of the lesion.
Histologically, the tophi have several features:
Acellular amorphous material Macrophages
Foreign body giant cells
In this patient, the joint space is preserved on the plain radiographs. The biopsy specimen has the characteristic features of gout -acellular amorphous material, macrophages, and foreign body giant cells.
The treatment of gout includes nonsteroidal anti-inflammatory drugs and medications such as allopurinol and colchicines, which lower hyperuricemia.
Correct Answer: Nonsteriodal anti-inflammatory agents
Slide 1 Slide 2 Slide 3 Slide 4
A 60-year-old man has severe knee pain. His plain radiographs are shown in Slide 1. His T1- and T2-weighted sagittal magnetic resonance images (MRIs) are shown in Slides 2 and 3. A biopsy specimen is shown in Slide 4. The most likely diagnosis is:
1) Coccidioidomycosis
3) Rheumatoid arthritis
2) Pigmented villonodular synovitis
5) Tuberculosus
4) Gout
Gout is caused by the deposition of monosodium urate crystals in tissues, typically around joints. Common locations of gout include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first affected location is the great toe. Gout commonly occurs inside a joint for two reasons - synovial fluid is a poorer solvent than plasma and lower temperatures (as in peripheral joints) favor crystallization.
Neutrophils ingest the crystals and release potent lysosomal enzymes. Punched lesions may be seen on radiographs in chronic cases, and one can often see an overlying lip of cortex at the edge of the lesion.
Histologically, the tophi have several features:
Acellular amorphous material Macrophages
Foreign body giant cells
In this patient, the joint space is preserved on the plain radiographs. The MRI scans show periarticular erosions. The biopsy specimen has the characteristic features of gout - acellular amorphous material, macrophages, and foreign body giant cells.
Correct Answer: Gout