Free Test MCQs/SBAs Orthopaedic Basic Sciences

Best answer: B .
The structure shown is the exiting nerve root at the L3-4 disk, which is the right L3 root. It supplies motor innervation to the iliopsoas via its contribution to the femoral nerve and sensory innervation to the anteromedial thigh and medial aspect of the lower leg through its dermatome.

Best answer : A .
Based on the stress-strain curve in Figure , ceramic has the highest modulus of elasticity. Young’s modulus is a measure of the stiffness (ability to resist deformation) of a material in the elastic zone that is calculated by measuring the slope of the stress-strain curve in the elastic zone. A higher modulus of elasticity indicates a stiffer material. Relative values of Young’s modulus include: (1) ceramic, (2) alloy, (3) stainless steel, (4) titanium, (5) cortical bone, (6) matrix polymers, (7) PMMA, polyethylene, (9) cancellous bone, (10) tendon/ligaments, and (11) cartilage.

Best answer: E .
The arrow points to the ischial spine and is the site of attachment of the sacrospinous ligament which anatomically divides the greater and lesser sciatic notches. The contents of the greater sciatic notch include the piriformis, the superior and inferior gluteal vessels and nerves, the sciatic and posterior femoral cutaneous nerves, the internal pudendal vessels, and the nerves to the obturator internus and quadratus femoris. The lesser sciatic notch is home to the tendon of the obturator internus, the nerve which supplies that muscle, and the internal pudendal vessels and nerve that course back through the lesser notch after having exited the greater notch.

Best Answer : D .
Open chain exercises are movements where the end of the kinetic chain(foot)is moving freely not fixed to floor or a wall.also isotonic contraction,constant m contraction throughout range of motion.

Best answer: E .
Kniest syndrome (spondyloepiphyseal dysplasia) is condition that involves a disproportionate dwarf. Patients have a short trunk and limbs with large joints. It is inherited in an autosomal dominant pattern and is caused by mutations in the COL2A1 gene. Kniest syndrome involves all zones of the growth plate as there is a defective collage II molecule assembly.

Best answer : D .
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 –kB ligand (RANKL). RANKL binds to osteoclast precursor cells for the formation of active osteoclasts.