Lower Limb Anatomy MCQ Question with answers and explanation | Part – 1
1.skin sensation and paralysis of muscles on the plantar aspect of the medial side of the foot. Which of the following nerves is most likely damaged?
(A) Common peroneal
(C) Superfi cial peroneal
(D) Deep peroneal
2. A patient with a deep knife wound in the buttock walks with a waddling gait that is characterized by the pelvis falling toward one side at each step. Which of the following nerves is damaged?
(A) Obturator nerve
(B) Nerve to obturator internus
(C) Superior gluteal nerve
(D) Inferior gluteal nerve
(E) Femoral nerve
3. A patient is unable to prevent anterior displacement of the femur on the tibia when the knee is fl exed. Which of the following ligaments is most likely damaged?
(A) Anterior cruciate
(B) Fibular collateral
(D) Posterior cruciate
(E) Tibial collateral
4. A 41-year-old man was involved in a fi ght and felt weakness in extending the knee joint. On examination, he was diagnosed with a lesion of the femoral nerve. Which of the following symptoms would be a result of this nerve damage?
(A) Paralysis of the psoas major muscle
(B) Loss of skin sensation on the lateral side of the foot
(C) Loss of skin sensation over the greater trochanter
(D) Paralysis of the vastus lateralis muscle
(E) Paralysis of the tensor fasciae latae
5. A 47-year-old woman is unable to invert her foot after she stumbled on her driveway. Which of the following nerves are most likely injured?
(A) Superfi cial and deep peroneal
(B) Deep peroneal and tibial
(C) Superfi cial peroneal and tibial
(D) Medial and lateral plantar
(E) Obturator and tibial
6. A 22-year-old patient is unable to “unlock” the knee joint to permit fl exion of the leg. Which of the following muscles is most likely damaged?
(A) Rectus femoris
(E) Biceps femoris
7. A patient presents with sensory loss on adjacent sides of the great and second toes and impaired dorsifl exion of the foot. These signs probably indicate damage to which of the following nerves?
(A) Superfi cial peroneal
(B) Lateral plantar
(C) Deep peroneal
8. A motorcyclist falls from his bike in an accident and gets a deep gash that severs the superficial peroneal nerve near its origin. Which of the following muscles is paralyzed?
(A) Peroneus longus
(B) Extensor hallucis longus
(C) Extensor digitorum longus
(D) Peroneus tertius
(E) Extensor digitorum brevis
9. A 67-year-old patient has been given a course of antibiotics by gluteal intramuscular injections after a major abdominal surgery. To avoid damaging the sciatic nerve during an injection, the needle should be inserted into which of the following areas?
(A) Over the sacrospinous ligament
(B) Midway between the ischial tuberosity and the lesser trochanter
(C) Midpoint of the gemelli muscles
(D) Upper lateral quadrant of the gluteal region
(E) Lower medial quadrant of the gluteal region
10. A 20-year-old patient cannot fl ex and medially rotate the thigh while running and climbing. Which of the following muscles is most likely damaged?
(C) Rectus femoris
(D) Vastus intermedius
(E) Tensor fasciae latae
1. The Answer is B. The common peroneal nerve divides into the deep peroneal nerve, which innervates the anterior muscles of the leg and supplies the adjacent skin of the fi rst and second toes, and the superfi cial peroneal nerve, which innervates the lateral muscles of the leg and supplies the skin on the side of the lower leg and the dorsum of the ankle and foot. The sural nerve supplies the lateral aspect of the foot and the little toe.
2. The Answer is C. The superior gluteal nerve innervates the gluteus medius muscle. Paralysis of this muscle causes gluteal gait, a waddling gait characterized by a falling of the pelvis toward the unaffected side at each step. The gluteus medius muscle normally functions to stabilize the pelvis when the opposite foot is off the ground. The inferior gluteal nerve innervates the gluteus maximus, and the nerve to the obturator internus supplies the obturator internus and superior gemellus muscles. The obturator nerve innervates the adductor muscles of the thigh, and the femoral nerve supplies the fl exors of the thigh.
3. The Answer is D. The posterior cruciate ligament is important because it prevents forward displacement of the femur on the tibia when the knee is fl exed. The anterior cruciate ligament prevents backward displacement of the femur on the tibia.
4. The answer is D. The femoral nerve innervates the quadratus femoris, sartorius, and vastus muscles. Therefore, damage to this nerve results in paralysis of these muscles. The second and third lumbar nerves innervate the psoas major muscle, the sural nerve innervates the skin on the lateral side of the foot, the iliohypogastric nerve and superior clunial nerves supply the skin over the greater trochanter, and the superior gluteal nerve innervates the tensor fasciae latae.
5. The Answer is B. The deep peroneal and tibial nerves innervate the chief evertors of the foot, which are the tibialis anterior, tibialis posterior, triceps surae, and extensor hallucis longus muscles. The tibialis anterior and extensor hallucis longus muscles are innervated by the deep peroneal nerve, and the tibialis posterior and triceps surae are innervated by the tibial nerve.
6. The Answer is C. The popliteus muscle rotates the femur laterally (“unlocks” the knee) or rotates the tibia medially, depending on which bone is fi xed. This action results in unlocking of the knee joint to initiate fl exion of the leg at the joint. The rectus femoris fl exes the thigh and extends the knee. The gastrocnemius fl exes the knee and plantar fl exes the foot. The semimembranosus extends the thigh and fl exes and rotates the leg medially. The biceps femoris extends the thigh and fl exes and rotates the leg laterally.
7. The Answer is C. The deep peroneal nerve supplies the anterior muscles of the leg, including the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus tertius muscles, which dorsifl ex the foot. The medial branch of the deep peroneal nerve supplies the skin of adjacent sides of the great and second toes, whereas the lateral branch supplies the extensor digitorum brevis and extensor hallucis brevis. The superfi cial peroneal nerve innervates the peroneus longus and brevis, which plantar fl exes the foot, and supplies the skin on the side of the lower leg and the dorsum of the ankle and foot. The tibial nerve innervates the muscles of the posterior compartment that plantar fl exes and supplies the skin on the heel and plantar aspect of the foot. The lateral plantar nerve innervates muscles and skin of the lateral plantar aspect of the foot. The sural nerve supplies the skin on the posterolateral aspect of the leg and the lateral aspect of the foot and the little toe.
8. The Answer is A. The superfi cial peroneal nerve supplies the peroneus longus and brevis muscles. Other muscles are innervated by the deep peroneal nerve.
9. The Answer is D. To avoid damaging the sciatic nerve during an intramuscular injection, the clinician should insert the needle in the upper lateral quadrant of the gluteal region. The inserted needle in the lower medial quadrant may damage the pudendal and sciatic nerves. The inserted needle midway between the ischial tuberosity and the lesser trochanter may damage the sciatic and posterior femoral cutaneous nerves on the quadratus femoris. The inserted needle over the sacrospinous ligament may damage the pudendal nerve and vessels.
10. The Answer is E. The tensor fasciae latae can fl ex and medially rotate the thigh, so this is the muscle most likely damaged. The hamstring muscles (semitendinosus, semimembranosus, and biceps femoris) can extend the thigh and fl ex the leg. The sartorius can fl ex the thigh and leg. The rectus femoris can fl ex the thigh and extend the leg. The vastus intermedius can extend the leg.