Lower Limb — MCQs

Lower Limb Indian Medical PG Practice Questions and MCQs

Question 571: Which of the following hamstring muscles performs both hip extension and knee flexion?

A. Gracilis
B. Sartorius
C. Short head of biceps femoris
D. Semimembranosus (Correct Answer)

Explanation: ***Semimembranosus*** - The **semimembranosus** is one of the three **hamstring muscles** originating from the **ischial tuberosity** and crossing both the hip and knee joints. - Its origin proximal to the hip joint and insertion distal to the knee joint allow it to perform **hip extension** and **knee flexion**. - Along with **semitendinosus** and the **long head of biceps femoris**, it forms the true hamstring group. *Gracilis* - The **gracilis is NOT a hamstring muscle** - it belongs to the **medial thigh adductor group**. - It is primarily responsible for **hip adduction** and assists in **knee flexion** and internal rotation. - It does not perform hip extension. *Sartorius* - The **sartorius is NOT a hamstring muscle** - it is an **anterior thigh muscle**. - It is the longest muscle in the body, primarily involved in **flexing**, **abducting**, and **laterally rotating the hip**, and **flexing the knee**. - It performs hip flexion (opposite of extension). *Short head of biceps femoris* - While part of the biceps femoris muscle, the **short head originates from the femur** (not ischial tuberosity) and **does not cross the hip joint**. - It acts exclusively on the knee joint, performing **knee flexion** and external rotation. - Because it does not cross the hip joint, it **cannot perform hip extension**, distinguishing it from the other hamstring components.

Question 572: Unlocking of the knee to allow flexion is done by:

A. Popliteus (Correct Answer)
B. Biceps femoris
C. Gastrocnemius
D. Vastus medialis

Explanation: ***Popliteus*** - The **popliteus muscle** is responsible for "unlocking" the knee joint by causing a slight **internal rotation of the tibia** on the femur (in a weight-bearing limb) or **external rotation of the femur** on the tibia (in a non-weight-bearing limb). - This action disengages the fully extended, locked position of the knee, allowing the joint to flex. *Gastrocnemius* - The **gastrocnemius muscle** primarily acts to **plantarflex the ankle** and contributes to **knee flexion**. - It does not have a direct role in the rotational movement required to unlock the knee joint. *Biceps femoris* - The **biceps femoris** is one of the **hamstring muscles** and its main actions are **knee flexion** and **hip extension**. - While it flexes the knee, it does not perform the specific rotational movement needed to unlock the joint. *Vastus medialis* - The **vastus medialis** is part of the **quadriceps femoris muscle** group and its primary action is **knee extension**. - It works antagonistically to knee flexion and plays no role in unlocking the knee.

Question 573: Which is the thickest nerve of the body?

A. Radial
B. Median
C. Sciatic (Correct Answer)
D. Axillary

Explanation: ***Sciatic*** - The **sciatic nerve** is the **longest and thickest nerve** in the human body, stemming from the sacral plexus. - It supplies motor and sensory innervation to the posterior thigh, and the entire lower leg and foot. *Radial* - The **radial nerve** originates from the brachial plexus and innervates extensor muscles of the arm, forearm, and hand. - While significant, it is not as large or thick as the sciatic nerve. *Median* - The **median nerve** also arises from the brachial plexus, primarily innervating muscles of the forearm and hand responsible for pronation and flexion. - It is smaller in diameter compared to the sciatic nerve. *Axillary* - The **axillary nerve** is a relatively short nerve derived from the brachial plexus, supplying the deltoid and teres minor muscles. - Its size is considerably smaller than the sciatic nerve and it provides innervation to a more limited area.

Question 574: Deltoid ligament is attached to all, except which structure?

A. Sustentaculum tali
B. Medial cuneiform (Correct Answer)
C. Navicular bone
D. Medial malleolus

Explanation: ***Medial cuneiform*** - The **deltoid ligament** is located on the **medial side of the ankle** and primarily connects the **tibia** to several tarsal bones. It does not attach to the medial cuneiform. - The **medial cuneiform** is a midfoot bone primarily involved in the **tarsometatarsal joint** and is not a direct attachment site for the deltoid ligament. *Medial malleolus* - The **medial malleolus**, the distal end of the **tibia**, serves as the **proximal attachment point** for all four parts of the deltoid ligament. - This strong connection is crucial for **stabilizing the ankle joint** medially. *Navicular bone* - The **tibionavicular part** of the deltoid ligament attaches to the **tuberosity of the navicular bone**. - This attachment helps **limit excessive abduction** and **eversion** of the foot. *Sustentaculum tali* - The **tibiocalcaneal part** of the deltoid ligament attaches to the **sustentaculum tali** on the calcaneus. - This attachment provides significant stability to the **subtalar joint**.

Question 575: At which joint does inversion of the foot occur?

A. Talocrural
B. Talocalcaneal (Correct Answer)
C. Calcaneocuboid
D. Cuneonavicular

Explanation: ***Talocalcaneal*** - The **talocalcaneal joint**, also known as the **subtalar joint**, is primarily responsible for **inversion** and **eversion** of the foot. - This joint allows the foot to **tilt inward (inversion)** or outward (eversion), movements crucial for adapting to uneven surfaces. *Talocrural* - The **talocrural joint**, or **ankle joint**, is responsible for **dorsiflexion** and **plantarflexion** of the foot. - It allows the foot to move up and down, but has limited role in inversion or eversion movements. *Calcaneocuboid* - The **calcaneocuboid joint** is a component of the **transverse tarsal joint** and contributes to the overall flexibility of the midfoot. - While it plays a role in stabilizing the foot, its movements are primarily **gliding**, and it is not the primary site for inversion. *Cuneonavicular* - The **cuneonavicular joint** connects the **cuneiforms** and the **navicular bone**, and is part of the **midfoot**. - This joint allows for limited **gliding movements** that contribute to the foot's adaptability, but it does not perform inversion.

Question 576: Which of the following muscles is primarily responsible for plantar flexion?

A. Tibialis posterior
B. Soleus
C. Plantaris
D. Gastrocnemius (Correct Answer)

Explanation: ***Gastrocnemius*** - The **gastrocnemius** is a powerful superficial muscle of the calf that, along with the soleus, forms the triceps surae. - It is primarily responsible for **plantar flexion of the ankle** and also assists in knee flexion. *Plantaris* - The **plantaris** is a small, slender muscle that aids weakly in plantar flexion and knee flexion. - Its contribution to overall plantar flexion strength is **minimal** compared to the gastrocnemius and soleus. *Tibialis posterior* - The **tibialis posterior** primarily functions in **inversion of the foot** and also contributes to plantar flexion. - It plays a crucial role in maintaining the **medial longitudinal arch** of the foot. *Soleus* - The soleus is a broad, flat muscle located deep to the gastrocnemius, and it is a major contributor to **plantar flexion**. - Unlike the gastrocnemius, the soleus only crosses the ankle joint, making its action **independent of knee position**.

Question 577: Which one of the following arteries pierces the oblique popliteal ligament of the knee joint?

A. Medial superior genicular artery
B. Lateral superior genicular artery
C. Middle genicular artery (Correct Answer)
D. Posterior tibial recurrent artery

Explanation: Detailed anatomical study reveals that the **middle genicular artery**, a branch of the popliteal artery, is unique among the genicular arteries in that it **pierces the oblique popliteal ligament**. It then supplies the **cruciate ligaments**, synovial membrane, and the posterior aspect of the **menisci** within the knee joint. *Medial superior genicular artery* - This artery runs **above the medial condyle of the femur** and contributes to the genicular anastomosis around the knee joint. - It does **not pierce the oblique popliteal ligament**; instead, it passes superficial to it. *Lateral superior genicular artery* - This artery passes **above the lateral condyle of the femur**, contributing to the blood supply of the knee joint. - Like the medial superior genicular artery, it runs **superficial to the oblique popliteal ligament**, rather than piercing it. *Posterior tibial recurrent artery* - The **posterior tibial recurrent artery** is a variable branch, usually originating from the posterior tibial artery, which ascends to the knee. - It typically supplies the posterior aspects of the knee joint but **does not pierce the oblique popliteal ligament**.

Question 578: Which of the following statements is true regarding the saphenous opening?

A. Allows passage of the Great Saphenous Vein (Correct Answer)
B. Forms an opening in the fascia
C. Covered by superficial fascia
D. Located superomedial to the pubic tubercle

Explanation: ***Allows passage of the Great Saphenous Vein*** - The saphenous opening is a gap in the **fascia lata** that allows the **great saphenous vein** to pass through and drain into the **femoral vein** [1]. - This is the **primary anatomical and clinical significance** of the saphenous opening [1]. - This anatomical arrangement is crucial for venous return from the lower limb [1]. *Located superomedial to the pubic tubercle* - This is **incorrect** - the saphenous opening is actually located **inferolateral** (not superomedial) to the pubic tubercle. - It lies approximately 3-4 cm inferolateral to the pubic tubercle, within the **femoral triangle**. *Forms an opening in the fascia* - While technically true that it is an opening in the **fascia lata**, this statement is too **vague and non-specific**. - It doesn't specify which fascia or convey the functional/clinical significance of the opening. - The more precise answer identifies its primary function (passage of the great saphenous vein). *Covered by superficial fascia* - This is **misleading** - the saphenous opening is covered by the **cribriform fascia**, which is a specialized, perforated modification of the superficial fascia. - Saying it's simply "covered by superficial fascia" doesn't capture the specific anatomical structure (cribriform fascia) that fills this opening.

Question 579: The nutrient artery to the fibula arises from which artery?

A. Peroneal artery (Correct Answer)
B. Anterior tibial artery
C. Posterior tibial artery
D. Popliteal artery

Explanation: ***Peroneal artery*** - The **peroneal artery** (also known as the fibular artery) is the primary blood supply to the fibula, giving rise to its largest **nutrient artery**. - This artery typically arises from the **posterior tibial artery** and courses along the posterior compartment of the leg, providing branches to the fibula. *Anterior tibial artery* - The **anterior tibial artery** primarily supplies the anterior compartment of the leg, including muscles and the tibia, but not the fibula's main nutrient artery. - It descends into the foot to become the **dorsalis pedis artery**. *Posterior tibial artery* - While the **peroneal artery** often originates from the posterior tibial artery, the posterior tibial artery itself does not directly give rise to the main **nutrient artery of the fibula**. - Its main function is to supply the posterior compartment muscles and the tibia, as well as several branches to the foot. *Popliteal artery* - The **popliteal artery** is a large artery in the posterior knee that bifurcates into the anterior and **posterior tibial arteries**. - It is too far proximal to directly give rise to the fibula's nutrient artery; its branches supply more proximal structures around the knee.

Question 580: Altered sensation over the area of the great saphenous vein in the leg is seen due to an injury to which of the following nerves?

A. Fibular
B. Femoral (Correct Answer)
C. Tibial
D. Sural

Explanation: ***Femoral*** - The **femoral nerve** gives rise to the **saphenous nerve**, which runs with the great saphenous vein and provides sensation to the medial aspect of the leg and foot. - Injury to the femoral nerve or its saphenous branch can result in altered sensation in the distribution of the **great saphenous vein**. *Tibial* - The **tibial nerve** innervates muscles in the posterior compartment of the leg and provides sensation to the sole of the foot and parts of the ankle, not the area of the great saphenous vein. - Injury to the tibial nerve often leads to **motor deficits** (plantar flexion) and sensory loss on the bottom of the foot. *Sural* - The **sural nerve** provides sensation to the posterolateral aspect of the leg and the lateral side of the foot, distinct from the great saphenous vein's territory. - This nerve is often injured during procedures around the **lateral malleolus** or Achilles tendon. *Fibular* - The **fibular nerve** (also known as the common peroneal nerve) innervates the anterior and lateral compartments of the leg and provides sensation to the dorsum of the foot and lateral leg. - Injury typically results in **foot drop** and sensory loss **dorsum of foot**.

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Gluteal Region and Hip

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Thigh and Popliteal Fossa

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Leg and Foot

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Joints of Lower Limb

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Nerves of Lower Limb

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Arterial Supply and Venous Drainage

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Lymphatic Drainage

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Muscles and Their Actions

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Gait Analysis and Biomechanics

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Applied Anatomy and Clinical Correlations

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Lower Limb — MCQs

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