Biology, Genetics & Bone Healing MCQs

Intermittent administration of low-dose parathyroid hormone (PTH), such as teriparatide, is used to treat severe osteoporosis. The primary mechanism underlying its anabolic effect on bone is:

An infant presents with multiple fractures and generalized increased bone density on radiographs, lacking clear medullary canals. The severe infantile form of this disease is most commonly caused by a mutation affecting which of the following?

A 35-year-old woman is diagnosed with an aggressive giant cell tumor of the distal femur. She is prescribed denosumab to shrink the tumor prior to surgical curettage. Denosumab exerts its effect in this disease process by binding directly to which of the following targets?

A 45-year-old man undergoes distraction osteogenesis of the tibia using an Ilizarov frame following a complex nonunion. The formation of new bone in the distraction gap primarily occurs via which of the following biologic processes?

The resistance of articular cartilage to compressive loads is primarily provided by which of the following extracellular matrix components?

During the incorporation of a structural cortical bone allograft, the process by which osteoclasts resorb the graft and osteoblasts lay down new viable bone is termed:

A 68-year-old woman with severe osteoporosis is started on teriparatide. Which of the following describes the mechanism by which this medication increases bone mineral density?

Which of the following histologic findings is the hallmark of Paget disease of bone in its mixed phase?

A 65-year-old woman is starting treatment for severe osteoporosis. Her physician prescribes a medication that acts as a recombinant form of parathyroid hormone (PTH). What is the primary mechanism of action of this drug when administered intermittently?

A 20-year-old man develops a large, eccentric, lytic lesion in the distal femur epiphysis. Biopsy shows numerous multinucleated giant cells in a background of mononuclear stromal cells. The neoplastic cells in this tumor express high levels of which of the following?

A 40-year-old woman is diagnosed with osteomalacia. Laboratory evaluation is likely to show which of the following profiles?

A 7-year-old child sustains a fracture. During the repair process, which cells are primarily responsible for clearing the necrotic tissue and hematoma in the initial inflammatory phase?

What is the primary function of sclerostin in bone metabolism?

According to Perren's strain theory, which type of tissue will primarily form in a fracture gap subjected to 5% to 10% strain?

A patient with a congenital disorder presents with multiple fractures, anemia, and cranial nerve palsies. Radiographs show a "bone-within-a-bone" appearance and diffuse sclerosis. The primary cellular defect involves an inability to produce an acidic extracellular environment due to a mutation affecting:

A 32-year-old woman presents with knee pain. Radiographs reveal an eccentric, lytic epiphyseal lesion in the proximal tibia. Biopsy shows multinucleated giant cells in a background of mononuclear stromal cells. The neoplastic cells in this lesion primarily express which of the following?

A 68-year-old man has bowing of his tibiae and an increasing hat size. Radiographs show cortical thickening and coarse trabeculae. Histologic evaluation of his affected bone is most likely to show:

Rigid plate fixation of a transverse diaphyseal fracture using absolute stability principles primarily results in which type of bone healing?

Which of the following cell types primarily expresses RANKL, a crucial cytokine for the regulation of osteoclast differentiation and activation?

A 30-year-old woman presents with knee pain. Radiographs show an eccentric, lytic epiphyseal-metaphyseal lesion of the proximal tibia. Biopsy shows multinucleated giant cells in a mononuclear stroma. Denosumab therapy, used for un-resectable cases, targets which molecule?