Lower Limb Anatomy (Nerves, Vessels, Joints) MCQs

Anatomy · 72 free questions with answers & explanations.

1. A patient sustained a posterior dislocation of the hip. Examination reveals the thigh is in flexion, adduction, and internal rotation. Which nerve is most commonly injured in this setting?
2. Foot drop in a patient following a fibular neck fracture results from injury to which nerve?
3. The femoral triangle contains which structures from medial to lateral (VAN mnemonic)?
4. Which ligament of the knee is the primary restraint against anterior displacement of the tibia on the femur, commonly torn in a valgus and external rotation injury?
5. Trendelenburg gait after a superior gluteal nerve palsy is due to paralysis of which muscle?
6. A patient sustains a posterior dislocation of the hip and subsequently develops loss of dorsiflexion and eversion of the foot, with preserved knee flexion and plantar flexion. The nerve injured is:
7. A patient injures the femoral nerve at the level of the inguinal ligament. Which functional deficit would be ABSENT in this lesion, distinguishing it from a lumbar plexus lesion at L2–L4?
8. On MRI of a knee, the posterior cruciate ligament (PCL) is shown to be intact while the anterior cruciate ligament (ACL) is torn. The clinical test MOST specific for ACL insufficiency — and the anatomical basis for its positivity — is:
9. A patient sustains a posterior dislocation of the hip and develops foot drop with sensory loss over the dorsum of the foot but intact sensation on the sole and intact eversion. Which nerve is injured?
10. The femoral sheath is a fascial compartment that encloses structures as they pass beneath the inguinal ligament. From lateral to medial, what is the correct arrangement of the contents?
11. Which muscles form the medial wall of the popliteal fossa and are tested by 'standing on tiptoe'?
12. Tarsal tunnel syndrome results from compression of the tibial nerve in the tarsal tunnel. What is the roof of the tarsal tunnel?
13. A footballer sustains a contact injury with a valgus force to the knee followed by forced external rotation. He hears a 'pop' and has immediate effusion with a positive anterior drawer test and positive McMurray's test. The 'unhappy triad' (O'Donoghue) injuries classically involve which three structures?
14. The femoral nerve emerges from the lateral border of psoas major and passes under the inguinal ligament lateral to the femoral vessels. It divides immediately below the inguinal ligament. Which is the LARGEST and most clinically important branch that continues down the medial side of the leg to the medial malleolus?
15. Following posterior hip dislocation, a patient develops foot drop with preserved knee flexion and hamstring function. Which nerve is most specifically injured?
16. The popliteal artery, the deepest structure in the popliteal fossa, gives off five genicular branches. Which of the following is a direct continuation of the popliteal artery after it exits the fossa by passing deep to the fibrous arch of soleus?
17. Tarsal tunnel syndrome involves compression of the posterior tibial nerve beneath the flexor retinaculum behind the medial malleolus. Which muscles in the foot are typically spared because they are innervated by a branch arising proximal to the tunnel?
18. A patient presents with inability to dorsiflex the foot and extend the toes, with foot drop and numbness over the first web space dorsally. Tibialis anterior is paralyzed but tibialis posterior is intact. Which nerve is most likely injured?
19. Femoral nerve is tested by which reflex, and injury at the level of the femoral triangle would spare which specific muscle group compared to a lesion at the inguinal ligament level?
20. Piriformis syndrome involves compression of which nerve as it exits through or below the piriformis muscle, and presents with pain radiating down the posterior thigh mimicking lumbar disc herniation?
21. The cruciate anastomosis around the hip joint involves four arteries. Which artery is NOT part of the cruciate anastomosis?
22. Following an acetabular fracture, a patient develops inability to extend the knee, loss of sensation over the anterior thigh and medial leg, and absent knee jerk. The femoral nerve is injured. Where is the most likely site of injury?
23. A patient with posterior dislocation of the hip develops footdrop and loss of sensation over the dorsum of the foot. Which nerve is injured and by what mechanism?
24. The unhappy triad (O'Donoghue's triad) of the knee involves which three structures?
25. A patient presents with inability to invert the foot, numbness over the sole, and pain behind the medial malleolus after wearing a tight cast. The tarsal tunnel contains all of the following EXCEPT:
26. A 60-year-old patient with osteoarthritis requiring total hip replacement is at risk for injury to which nerve during the posterior approach to the hip?
27. A patient sustains a posterior dislocation of the hip joint. On examination, the leg is held in flexion, adduction, and internal rotation, and there is weakness of hip abduction. Which nerve is most commonly injured in posterior hip dislocation?
28. A patient with knee pain and an audible 'click' is diagnosed with a medial meniscus tear. Which anatomical relationship makes the medial meniscus more susceptible to injury than the lateral meniscus?
29. After a tight below-knee plaster cast is applied for an ankle fracture, the patient develops severe foot pain, paresthesia along the dorsum of the foot and first web space, and weakness of foot dorsiflexion and toe extension. Which nerve is compressed?
30. During a total hip replacement through the posterior approach, the surgeon must detach and later repair the short external rotators. Which muscle forms the key landmark for identifying the sciatic nerve in this approach?
31. A patient with a proximal tibial fracture develops weakness of plantar flexion with intact sensation on the sole of the foot. Which nerve structure has been injured?
32. A patient with a posterior hip dislocation presents with loss of hip extension, external rotation, and abduction power, along with foot drop. The sciatic nerve is injured. Which division of the sciatic nerve is characteristically injured FIRST in posterior hip dislocation and fractures of the acetabulum?
33. A patient develops inability to extend the knee, loss of knee jerk, and sensory loss over the anterior and medial thigh and medial leg. The nerve injured is the femoral nerve. Which compartment of the thigh is most commonly affected if a femoral nerve block inadvertently spreads?
34. In a patient with tarsal tunnel syndrome, which nerve is compressed and at what anatomical location?
35. The obturator nerve (L2–L4) exits the pelvis through the obturator foramen. A patient with an obturator hernia presents with sensory changes along the medial thigh and knee pain. What is this referred knee pain called, and which branch of the obturator nerve causes it?
36. A patient who underwent prolonged lithotomy position during surgery presents with inability to dorsiflex the foot and evert it, with numbness over the lateral leg and dorsum of foot. The deep peroneal nerve is intact (ankle dorsiflexion partially preserved). Which nerve is most likely compressed?
37. The femoral nerve (L2-L4) may be injured during inguinal lymph node dissection or psoas haematoma. A complete femoral nerve lesion would produce all of the following EXCEPT:
38. During a posterior approach to total hip replacement, the piriformis muscle is a key surgical landmark. Which important neurovascular structure lies inferior to piriformis in the greater sciatic foramen and is most at risk in posterior hip dislocations?
39. Tarsal tunnel syndrome involves compression of the tibial nerve behind the medial malleolus, beneath the flexor retinaculum. Which specific muscles in the foot would be denervated?
40. A 35-year-old patient develops foot drop and sensory loss over the dorsum of the foot and lateral leg after prolonged squatting. The nerve injured most commonly at the fibular neck is the common fibular (peroneal) nerve. Which specific division causes foot drop (loss of dorsiflexion and eversion)?
41. The saphenous nerve, a branch of the femoral nerve, is at particular risk during which common surgical procedure because of its anatomical course in the subsartorial (Hunter's) canal?
42. In a posterior approach to total hip arthroplasty, the sciatic nerve is at risk. In what percentage of individuals does the common fibular division of the sciatic nerve pass through the piriformis muscle rather than below it, making it more vulnerable?
43. The cruciate anastomosis around the hip joint is important for collateral circulation following femoral artery occlusion. Which four arteries contribute to this anastomosis?
44. In meralgia paresthetica, burning pain and numbness over the lateral thigh results from entrapment of the lateral femoral cutaneous nerve (LFCN). Which space does this nerve traverse to exit the pelvis, making it susceptible to entrapment?
45. During posterior hip replacement, the piriformis muscle is an important landmark. Which nerve runs immediately inferior to the piriformis and exits the greater sciatic foramen below it, making it most vulnerable in posterior hip approaches?
46. The popliteal fossa contents from lateral to medial are — lateral to medial: common peroneal nerve, tibial nerve, popliteal vein, popliteal artery. In popliteal artery aneurysm, which structure is most likely to be compressed, causing foot drop?
47. A patient has foot drop after total hip arthroplasty. Intraoperative stretching of the sciatic nerve most often damages which division, producing selective weakness?
48. The popliteal artery terminates by dividing into the anterior tibial artery and the tibioperoneal trunk at which level?
49. The sciatic nerve divides into tibial and common peroneal components. At which level does this division typically occur?
50. A patient develops foot drop after total hip replacement in the left lateral decubitus position. Which nerve and which part of it is most likely injured?
51. The saphenous nerve (terminal branch of the femoral nerve) accompanies the great saphenous vein distal to the knee. It provides sensory supply to which specific area?
52. A 35-year-old runner complains of numbness along the dorsum of the foot with weakness of toe and foot dorsiflexion after wearing tight ski boots. The nerve most likely compressed at the anterior tarsal tunnel is:
53. At the popliteal fossa, the popliteal artery lies in which relationship to the popliteal vein and the tibial nerve?
54. A patient has foot drop, loss of dorsiflexion and eversion, and sensory loss over the dorsum of the foot and lateral lower leg. Inversion and plantar flexion are preserved. The lesion is in the:
55. The femoral artery becomes the popliteal artery as it passes through which structure?
56. A patient develops lateral compartment syndrome of the leg following a fibular neck fracture. Which nerve is most vulnerable as it winds around the neck of the fibula, and what is the precise sensory loss pattern if it is injured?
57. The great saphenous vein is used for long saphenous vein grafting in CABG. At which constant surface landmark can it be reliably identified at the ankle for surgical cut-down?
58. The obturator nerve (L2–L4) passes through the obturator foramen and divides into anterior and posterior divisions. Which muscle does the POSTERIOR division of the obturator nerve innervate that is NOT innervated by the anterior division?
59. The popliteal artery divides into its terminal branches at the inferior border of the popliteus muscle. Which is the larger terminal branch and at what anatomical landmark does it divide?
60. The common peroneal (fibular) nerve winds around the neck of the fibula and is vulnerable to injury. Isolated common peroneal nerve palsy at the fibular neck produces which complete motor deficit?
61. The deep peroneal nerve (deep fibular nerve) enters the anterior compartment of the leg by passing through the anterior intermuscular septum. Its terminal branches in the foot supply:
62. A patient with a hip fracture is found to have an intact hip joint but later develops avascular necrosis of the femoral head. Which vessel is most commonly responsible for the blood supply to the femoral head that is disrupted?
63. The popliteal fossa contents from superficial to deep in its floor include all of the following in order EXCEPT:
64. The piriformis muscle serves as a landmark in the greater sciatic foramen. Which nerve exits the greater sciatic foramen ABOVE the piriformis?
65. A patient presents with inability to evert the foot, loss of sensation over the dorsum of the foot (excluding the first web space and the medial border), and foot drop. The nerve most likely injured is:
66. The femoral artery becomes the popliteal artery as it passes through which aperture?
67. The great saphenous vein (GSV) drains into the femoral vein at the saphenofemoral junction. Its surface marking for this junction is:
68. A 28-year-old footballer suffers a valgus stress injury to the knee. Examination reveals excessive lateral displacement of the tibia on the femur and a positive Lachman test. Which structure is primarily damaged?
69. Following a posterior dislocation of the hip, a patient develops weakness of dorsiflexion and eversion of the foot, along with sensory loss over the dorsum of the foot. Which nerve is injured?
70. The femoral triangle contains several important neurovascular structures arranged from lateral to medial. Which is the correct lateral-to-medial order of its contents within the femoral sheath?
71. A patient with tarsal tunnel syndrome presents with burning pain and paresthesia over the sole and toes. Which structure passes through the tarsal tunnel immediately posterior to the medial malleolus?
72. During a total hip replacement, the surgeon takes a posterior approach. Which muscle is the primary rotator cuff equivalent of the hip that must be carefully repaired to prevent postoperative dislocation?