Advanced Semimembranosus Quiz

Q1. Why is semimembranosus considered a true hamstring muscle?

• It arises from the femur and receives femoral nerve supply
• It is supplied by the obturator nerve
• It crosses only the knee
• It has the classic pelvic origin, dual-joint course, and tibial sciatic innervation

Q2. How can a proximal tibial division sciatic nerve lesion affect semimembranosus?

• It can weaken its hip extension and knee flexion actions
• It selectively weakens ankle dorsiflexion only
• It causes isolated quadriceps paralysis
• It increases medial hamstring strength

Q3. What is the anatomical basis for semimembranosus contributing to posteromedial knee stability?

• It has no capsular relationship
• It inserts into the patella
• It forms the fibular collateral ligament
• Its distal tendon sends reinforcing expansions around the posteromedial knee

Q4. Why can a popliteal cyst be associated with the semimembranosus-gastrocnemius bursa?

• The bursa may communicate with the knee joint and become distended
• The tendon directly secretes synovial fluid
• The bursa communicates with the ankle joint
• The bursa lies inside the patella

Q5. How does knee extension affect semimembranosus length when the hip is flexed?

• It has no effect because the muscle crosses only the hip
• It shortens the muscle at both joints
• It further lengthens the biarticular muscle
• It converts the muscle into a knee extensor

Q6. Why can semimembranosus be strained during high-speed running?

• It undergoes rapid eccentric loading across the hip and knee
• It crosses only the ankle
• It remains completely inactive during running
• It acts only concentrically at a fixed length

Q7. Which distal expansion of semimembranosus is directed superiorly and laterally across the posterior knee?

• The pes anserinus
• The patellar retinaculum
• The iliotibial tract
• The expansion contributing to the oblique popliteal ligament

Q8. How does semimembranosus anatomy help distinguish it from semitendinosus during dissection?

• It lies in the anterior compartment
• It is broader and deeper with a flattened tendon and complex distal expansions
• It is more superficial with a long pes anserinus tendon
• It inserts on the fibular head

Q9. What deficit would most directly reflect loss of the rotational contribution of semimembranosus?

• Weak medial rotation of the flexed leg
• Weak lateral rotation of the flexed leg only
• Loss of ankle inversion
• Loss of knee extension

Q10. Which statement best integrates semimembranosus anatomy?

• It is a common-fibular-nerve-supplied leg muscle inserting on the fifth metatarsal
• It is an obturator-nerve-supplied adductor that crosses only the hip
• It is a medial hamstring with ischial origin, posteromedial tibial insertion, tibial sciatic innervation, and actions at both hip and knee
• It is a femoral-nerve-supplied quadriceps muscle inserting on the patella