Lower Limb Anatomy MCQ questions with answers and explanation | Part – 3
Questions :21 – 30
21. A 34-year-old woman sustains a deep cut on the dorsum of the foot just distal to her ankle joint by a falling kitchen knife. A physician in the emergency department has ligated the dorsalis pedis artery proximal to the injured area. Which of the following conditions most likely occurs as a result of the injury?
(A) Ischemia in the peroneus longus muscle
(B) Aneurysm in the plantar arterial arch
(C) Reduction of blood fl ow in the medial tarsal artery
(D) Low blood pressure in the anterior tibial artery
(E) High blood pressure in the arcuate artery
22. A patient experiences paralysis of the muscle that originates from the femur and contributes directly to the stability of the knee joint. Which of the following muscles is involved?
(A) Vastus lateralis
(D) Biceps femoris (long head)
(E) Rectus femoris
23. A patient is involved in a motorcycle wreck that results in avulsion of the skin over the anterolateral leg and ankle. Which of the following structures is most likely destroyed with this type of injury?
(A) Deep peroneal nerve
(B) Extensor digitorum longus muscle tendon
(C) Dorsalis pedis artery
(D) Great saphenous vein
(E) Superfi cial peroneal nerve
24. A knife wound penetrates the superfi cial vein that terminates in the popliteal vein. Bleeding occurs from which of the following vessels?
(A) Posterior tibial vein
(B) Anterior tibial vein
(C) Peroneal vein
(D) Great saphenous vein
(E) Lesser saphenous vein
25. A 10-year-old boy falls from a tree house. The resultant heavy compression of the sole of his foot against the ground caused a fracture of the head of the talus. Which of the following structures is unable to function normally?
(A) Transverse arch
(B) Medial longitudinal arch
(C) Lateral longitudinal arch
(D) Tendon of the peroneus longus
(E) Long plantar ligament
26. A 24-year-old woman complains of weakness when she extends her thigh and rotates it laterally. Which of the following muscles is paralyzed?
(A) Obturator externus
(C) Tensor fasciae latae
(D) Gluteus maximus
27. A patient with hereditary blood clotting problems presents with pain in the back of her knee. An arteriogram reveals a blood clot in the popliteal artery at its proximal end. Which of the following arteries will allow blood to reach the foot?
(A) Anterior tibial
(B) Posterior tibial
(D) Lateral circumfl ex femoral
(E) Superior medial genicular
28. A 72-year-old woman complains of a cramp-like pain in her thigh and leg. She was diagnosed as having a severe intermittent claudication. Following surgery, an infection was found in the adductor canal, damaging the enclosed structures. Which of the following structures remains intact?
(A) Femoral artery
(B) Femoral vein
(C) Saphenous nerve
(D) Great saphenous vein
(E) Nerve to the vastus medialis
29. A basketball player was hit in the thigh by an opponent’s knee. Which of the following arteries is likely to compress and cause ischemia because of the bruise and damage to the extensor muscles of the leg?
(B) Deep femoral
(C) Anterior tibial
(D) Posterior tibial
30. An elderly woman fell at home and fractured the greater trochanter of her femur. Which of the following muscles would continue to function normally?
(B) Obturator internus
(C) Gluteus medius
(D) Gluteus maximus
(E) Gluteus minimus
Answers and Explanations : 21-30
21. The Answer is C. Reduction of blood fl ow in the medial tarsal artery occurs because it is a branch of the dorsalis pedis artery, which begins at the ankle joint as the continuation of the anterior tibial artery. The anterior tibial and peroneal arteries supply the peroneus longus muscle. The deep plantar arterial arch is formed mainly by the lateral plantar artery. Blood pressure in the anterior tibial artery should be higher than normal. The arcuate artery should have a low blood pressure because it is a terminal branch of the dorsalis pedis artery.
22. The Answer is A. The vastus lateralis muscles arise from the femur and all the other muscles originate from the hip (coxal) bone. The biceps femoris inserts on the fi bula, and other muscles insert on the tibia; thus, all of them contribute to the stability of the knee joint.
23. The Answer is E. The superfi cial peroneal nerve emerges between the peroneus longus and peroneus brevis muscles and descends superfi cial to the extensor retinaculum of the ankle on the anterolateral side of the leg and ankle, innervating the skin of the lower leg and foot. The great saphenous vein begins at the medial end of the dorsal venous arch of the foot and ascends in front of the medial malleolus and along the medial side of the tibia along with the saphenous nerve. Other structures pass deep to the extensor retinaculum.
24. The Answer is E. The lesser (small) saphenous vein ascends on the back of the leg in company with the sural nerve and terminates in the popliteal vein. The peroneal vein empties into the posterior tibial vein. The anterior and posterior tibial veins are deep veins and join to form the popliteal vein. The great saphenous vein drains into the femoral vein.
25. The Answer is B. The keystone of the medial longitudinal arch of the foot is the head of the talus, which is located at the summit between the sustentaculum tali and the navicular bone. The medial longitudinal arch is supported by the spring ligament and the tendon of the fl exor hallucis longus muscle. The cuboid bone serves as the keystone of the lateral longitudinal arch, which is supported by the peroneus longus tendon and the long and short plantar ligaments. The transverse arch is formed by the navicular, three cuneiform, the cuboid, and fi ve metatarsal bones and is supported by the peroneus longus tendon and the transverse head of the adductor hallucis.
26. The Answer is D. The gluteus maximus can extend and rotate the thigh laterally. The obturator externus rotates the thigh laterally. The sartorius can fl ex both the hip and knee joints. The tensor fasciae latae can fl ex and medially rotate the thigh. The semitendinosus can extend the thigh and medially rotate the leg.
27. The Answer is D. If the proximal end of the popliteal artery is blocked, blood may reach the foot by way of the descending branch of the lateral circumfl ex femoral artery, which participates in the anastomosis around the knee joint. Other blood vessels are direct or indirect branches of the popliteal artery.
28. The Answer is D. The great saphenous nerve remains intact because it is not in the adductor canal. The adductor canal contains the femoral vessels, the saphenous nerve, and the nerve to the vastus medialis.
29. The Answer is C. A muscular spasm or hypertrophy of the extensor muscles of the leg may compress the anterior tibial artery, causing ischemia. The popliteal artery supplies muscles of the popliteal fossa. The deep femoral artery supplies deep muscles of the thigh. The posterior tibial and peroneal arteries supply muscles of the posterior and lateral compartments of the leg.
30. The Answer is D. The gluteus maximus is inserted into the gluteal tuberosity of the femur and the iliotibial tract. All of the other muscles insert on the greater trochanter of the femur, and their functions are impaired.