Lower Limb — MCQs

Lower Limb Indian Medical PG Practice Questions and MCQs

Question 271: A construction worker falls feet-first from a roof. He sustains a fracture of the groove on the undersurface of the sustentaculum tali of the calcaneus bone. Which of the following muscle tendons is most likely torn?

A. Flexor digitorum brevis
B. Flexor digitorum longus
C. Flexor hallucis brevis
D. Flexor hallucis longus (Correct Answer)

Explanation: ### Explanation The correct answer is **D. Flexor hallucis longus**. **1. Why Flexor Hallucis Longus (FHL) is correct:** The **sustentaculum tali** is a shelf-like bony projection on the medial aspect of the calcaneus. Its primary function is to support the talus. On its **inferior (undersurface)**, there is a distinct groove. The tendon of the **Flexor Hallucis Longus** passes through this groove as it travels from the posterior compartment of the leg into the sole of the foot. A fracture involving this specific groove directly jeopardizes the integrity of the FHL tendon. **2. Why the other options are incorrect:** * **Flexor digitorum longus (FDL):** While the FDL passes medially, it travels superior to the sustentaculum tali (along its medial border) rather than in the groove beneath it. * **Flexor digitorum brevis (FDB):** This is an intrinsic muscle of the first layer of the sole. It originates from the medial tubercle of the calcaneus, not the sustentaculum tali. * **Flexor hallucis brevis (FHB):** This is a short intrinsic muscle of the foot originating from the cuboid and cuneiform bones; it does not have a relationship with the calcaneal grooves. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Medial Malleolus structures (Ant to Post):** **T**ibialis posterior, flexor **D**igitorum longus, posterior tibial **A**rtery, tibial **N**erve, flexor **H**allucis longus (**T**om, **D**ick **A**nd **N**ervous **H**arry). * **FHL "The Great Climber’s Muscle":** It provides the final "push-off" during the gait cycle. * **Sustentaculum Tali:** It serves as an attachment point for the **Spring Ligament** (Plantar calcaneonavicular ligament), which is vital for maintaining the medial longitudinal arch. * **Fracture Mechanism:** Calcaneal fractures (Don Juan fractures) often occur due to axial loading (falls from height) and are frequently associated with lumbar spine compression fractures.

Question 272: "Anaesthesia on the sole of the foot" is caused by injury to which nerve?

A. Common peroneal nerve
B. Tibial nerve (Correct Answer)
C. Superficial peroneal nerve
D. Deep peroneal nerve

Explanation: The **Tibial nerve**, a terminal branch of the sciatic nerve, is responsible for the sensory innervation of the entire **sole of the foot**. After passing through the tarsal tunnel behind the medial malleolus, the tibial nerve divides into the **Medial and Lateral Plantar nerves**. These branches provide cutaneous sensation to the plantar surface (sole) and the plantar aspect of the toes. Therefore, an injury to the tibial nerve (e.g., at the level of the popliteal fossa or tarsal tunnel) results in anesthesia on the sole. **Analysis of Incorrect Options:** * **Common Peroneal Nerve (CPN):** This nerve supplies the lateral and anterior compartments of the leg. Injury typically leads to "Foot Drop" and sensory loss on the lateral leg and dorsum of the foot, not the sole. * **Superficial Peroneal Nerve:** A branch of the CPN, it supplies the lateral compartment muscles and provides sensation to the **dorsum of the foot** (except the first web space). * **Deep Peroneal Nerve:** This nerve supplies the anterior compartment muscles and provides sensory innervation strictly to the **first interdigital web space** on the dorsum of the foot. **Clinical Pearls for NEET-PG:** * **Tarsal Tunnel Syndrome:** Compression of the tibial nerve behind the medial malleolus leads to pain and paresthesia on the sole. * **Foot Drop:** Classically associated with injury to the **Common Peroneal Nerve** at the neck of the fibula. * **Sural Nerve:** Formed by contributions from both tibial and common peroneal nerves; it supplies the lateral border of the foot.

Question 273: What structure prevents the forward displacement of the tibia on the femur?

A. Anterior cruciate ligament (Correct Answer)
B. Posterior cruciate ligament
C. Medial collateral ligament
D. Lateral collateral ligament

Explanation: The stability of the knee joint is primarily maintained by four major ligaments. The **Anterior Cruciate Ligament (ACL)** is the primary stabilizer against **anterior (forward) displacement of the tibia** relative to the femur. It originates from the anterior intercondylar area of the tibia and ascends posterolaterally to attach to the medial aspect of the lateral femoral condyle. By resisting this forward translation, it prevents the tibia from "sliding out" from under the femur during weight-bearing and rotational movements. **Analysis of Incorrect Options:** * **B. Posterior Cruciate Ligament (PCL):** This is the strongest ligament of the knee. It prevents **posterior (backward) displacement** of the tibia on the femur. It is the primary stabilizer when the knee is flexed (e.g., walking downstairs). * **C. Medial Collateral Ligament (MCL):** This extrinsic ligament resists **valgus stress** (abduction of the leg at the knee) and provides mediolateral stability. * **D. Lateral Collateral Ligament (LCL):** This cord-like ligament resists **varus stress** (adduction of the leg at the knee). **High-Yield Clinical Pearls for NEET-PG:** * **Lachman Test:** The most sensitive clinical test for an ACL tear (more sensitive than the Anterior Drawer Test). * **Unhappy Triad of O'Donoghue:** A common sports injury involving simultaneous tears of the **ACL, MCL, and Medial Meniscus** (though recent studies suggest the Lateral Meniscus is more commonly involved in acute ACL tears). * **PCL Injury:** Often results from a "dashboard injury" where the proximal tibia hits the dashboard during a motor vehicle accident, forcing it posteriorly.

Question 274: Rider's bone ossifies in which of the following muscles?

A. Adductor Longus (Correct Answer)
B. Gluteus Maximus
C. Lateral head of Gastrocnemius
D. Tibialis Posterior

Explanation: **Explanation:** The correct answer is **Adductor Longus**. **Rider’s Bone** refers to the traumatic ossification (myositis ossificans) within the tendon of the **Adductor Longus** muscle. This condition occurs due to chronic, repetitive strain and friction of the medial thigh against the saddle during horseback riding. The constant micro-trauma leads to hematoma formation, which subsequently undergoes dystrophic calcification and ossification, resulting in a bony deposit within the muscle or its tendon. **Analysis of Incorrect Options:** * **Gluteus Maximus:** While it is a powerful extensor used in riding, it does not typically undergo ossification. * **Lateral head of Gastrocnemius:** This is the site for the **Fabella**, a common sesamoid bone found in the lateral head of the gastrocnemius. It is a normal anatomical variant, not a result of trauma. * **Tibialis Posterior:** This muscle is located in the deep posterior compartment of the leg and is not subject to the specific mechanical stresses associated with horseback riding. **High-Yield Clinical Pearls for NEET-PG:** * **Myositis Ossificans Traumatica:** This is the general term for bone formation inside a muscle following injury. * **Common Sites:** Besides the Adductor Longus (Rider’s bone), it is frequently seen in the **Brachialis** (following elbow dislocation) and **Quadriceps Femoris** (due to direct blows). * **Radiological Sign:** On X-ray, it typically shows a "zonal pattern" with a mature peripheral rim of bone and a radiolucent center, which helps differentiate it from osteosarcoma.

Question 275: Which nerve supplies the skin over the femoral triangle?

A. Iliohypogastric nerve
B. Ilioinguinal nerve
C. Genitofemoral nerve (Correct Answer)
D. Lateral femoral cutaneous nerve

Explanation: **Explanation:** The skin over the femoral triangle is primarily supplied by the **femoral branch of the genitofemoral nerve (L1, L2)**. This nerve enters the thigh by passing deep to the inguinal ligament, traveling within the lateral compartment of the femoral sheath. It pierces the fascia lata to supply the skin covering the upper part of the femoral triangle. **Analysis of Options:** * **Genitofemoral nerve (Correct):** Its femoral branch supplies the skin over the femoral triangle, while its genital branch supplies the cremaster muscle and scrotal/labial skin. * **Iliohypogastric nerve (L1):** Supplies the skin over the lateral gluteal region and the hypogastric region (above the pubis), but does not extend into the femoral triangle. * **Ilioinguinal nerve (L1):** Passes through the superficial inguinal ring to supply the skin over the root of the penis/scrotum (or labia majora) and a small area of the **upper medial thigh**, but not the central femoral triangle area. * **Lateral femoral cutaneous nerve (L2, L3):** Supplies the skin on the **lateral aspect** of the thigh down to the knee. It is frequently tested in the context of *Meralgia Paresthetica* (compression under the inguinal ligament). **High-Yield NEET-PG Pearls:** 1. **Cremasteric Reflex:** The afferent limb is the femoral branch of the genitofemoral nerve (or ilioinguinal nerve), and the efferent limb is the genital branch of the genitofemoral nerve. 2. **Femoral Nerve (L2-L4):** While it supplies the muscles of the anterior compartment, its cutaneous branch (Anterior Cutaneous Nerve of Thigh) supplies the skin of the **distal** two-thirds of the anterior thigh, not the proximal triangle area. 3. **Great Saphenous Vein:** Pierces the cribriform fascia within the femoral triangle to drain into the femoral vein.

Question 276: Which of the following statements about the great saphenous vein is true?

A. It is located posterior to the medial malleolus.
B. It drains into the popliteal vein.
C. It is located posterior to the medial condyles of the tibia and femur. (Correct Answer)
D. It is deep to the fascia lata of the thigh.

Explanation: ### Explanation The **Great Saphenous Vein (GSV)** is the longest vein in the body and a frequent topic in NEET-PG anatomy. [1] **1. Why Option C is Correct:** The GSV originates from the medial end of the dorsal venous arch of the foot. As it ascends the leg, it passes **anterior** to the medial malleolus. However, as it continues upward, it crosses the knee joint by passing **posterior to the medial condyles** of the tibia and the femur. This posterior positioning at the knee is a key anatomical landmark to avoid during surgical procedures. **2. Why the Other Options are Incorrect:** * **Option A:** The GSV passes **anterior** to the medial malleolus (accompanied by the saphenous nerve). [1] It is the *small saphenous vein* that passes posterior to the lateral malleolus. [1] * **Option B:** The GSV ascends the thigh and passes through the saphenous opening to drain into the **femoral vein**, not the popliteal vein. [1] The small saphenous vein typically drains into the popliteal vein. [1] * **Option C:** The GSV is a **superficial vein**. [1] It travels within the subcutaneous fat, superficial to the fascia lata, until it pierces the cribriform fascia at the saphenous opening to join the deep system. **Clinical Pearls for NEET-PG:** * **Saphenous Cut-down:** Performed 2 cm anterior and superior to the medial malleolus; the **saphenous nerve** is at risk of injury here, leading to loss of sensation on the medial side of the foot. [1] * **Coronary Artery Bypass Graft (CABG):** The GSV is commonly used as a graft due to its length and accessibility. * **Valves:** It contains approximately 10–12 valves, with the most constant one located at the saphenofemoral junction.

Question 277: The deep peroneal nerve provides sensory innervation to which of the following areas?

A. Anterolateral dorsum of the foot
B. Lateral part of the leg
C. The first web space (Correct Answer)
D. The fifth web space

Explanation: **Explanation:** The **Deep Peroneal Nerve (DPN)**, a terminal branch of the Common Peroneal Nerve, is primarily a motor nerve that supplies the muscles of the anterior compartment of the leg and the dorsum of the foot. However, it has a very specific and high-yield sensory distribution: it provides cutaneous innervation **only to the skin of the first interdigital cleft (the first web space)** between the great toe and the second toe. **Analysis of Options:** * **Option C (Correct):** The DPN pierces the deep fascia at the ankle and terminates by supplying the skin of the first web space. This is a classic "spot diagnosis" in anatomy exams. * **Option A (Incorrect):** The **Superficial Peroneal Nerve** supplies the majority of the dorsum of the foot and the anterolateral aspect of the lower leg. * **Option B (Incorrect):** The lateral part of the leg is supplied by the **Lateral Sural Cutaneous Nerve** (proximal) and the Superficial Peroneal Nerve (distal). * **Option D (Incorrect):** The fifth web space and the lateral border of the foot are supplied by the **Sural Nerve**. **Clinical Pearls for NEET-PG:** 1. **Anterior Tarsal Tunnel Syndrome:** Compression of the Deep Peroneal Nerve under the inferior extensor retinaculum leads to sensory loss specifically in the first web space and weakness of the Extensor Digitorum Brevis. 2. **Foot Drop:** Injury to the Common Peroneal Nerve (at the neck of the fibula) affects both the Deep and Superficial branches, leading to loss of dorsiflexion (Foot Drop) and eversion, along with sensory loss over the first web space and the dorsum of the foot. 3. **Mnemonic:** The Deep Peroneal Nerve goes **"Deep"** into the **"First"** gap.

Question 278: Which of the following is NOT an abductor of the hip joint?

A. Gluteus medius
B. Gluteus minimus
C. Gluteus maximus (Correct Answer)
D. Tensor fascia lata

Explanation: The primary movement of the hip joint is determined by the relationship of the muscle's insertion to the axis of the joint. **Explanation of the Correct Answer:** **C. Gluteus Maximus:** This is the largest and most superficial muscle of the gluteal region. Its primary functions are **extension** and **lateral (external) rotation** of the hip. While its superior fibers can assist in abduction, its main bulk acts as a powerful extensor (essential for climbing stairs or rising from a sitting position). Therefore, it is not classified as a primary abductor of the hip. **Explanation of Incorrect Options:** * **A & B. Gluteus Medius and Minimus:** These are the **primary abductors** of the hip. They originate from the outer surface of the ilium and insert into the greater trochanter. Their contraction pulls the femur away from the midline. * **D. Tensor Fascia Lata (TFL):** This muscle inserts into the iliotibial tract. Along with the gluteus medius and minimus, it acts as an abductor and medial rotator of the hip. **High-Yield Clinical Pearls for NEET-PG:** 1. **Trendelenburg Sign:** This occurs due to paralysis of the Gluteus medius and minimus (supplied by the **Superior Gluteal Nerve**). When the patient stands on the affected leg, the pelvis drops on the healthy side because the abductors fail to stabilize the pelvis. 2. **Nerve Supply:** Gluteus medius, minimus, and TFL are supplied by the **Superior Gluteal Nerve (L4-S1)**, whereas the Gluteus maximus is supplied by the **Inferior Gluteal Nerve (L5-S2)**. 3. **The "Climber's Muscle":** Gluteus maximus is the chief muscle used for powerful extension against resistance (running, jumping, climbing).

Question 279: The femoral artery begins at which anatomical landmark?

A. Mid-inguinal point (Correct Answer)
B. Femoral ring
C. Midpoint of the inguinal ligament
D. Any of the above

Explanation: The **femoral artery** is the direct continuation of the external iliac artery. It enters the thigh by passing deep to the inguinal ligament [1]. **1. Why "Mid-inguinal point" is correct:** The femoral artery begins exactly at the **mid-inguinal point**. This is a specific anatomical landmark defined as the point midway between the **Anterior Superior Iliac Spine (ASIS)** and the **Symphysis Pubis**. This is the site where the femoral pulse is most easily palpated and where the artery lies directly anterior to the head of the femur [1]. **2. Why other options are incorrect:** * **Midpoint of the inguinal ligament:** This is the point midway between the **ASIS** and the **Pubic Tubercle**. This landmark is used to locate the **deep inguinal ring**, which lies approximately 1.25 cm above it. It is not the site of the femoral artery's origin. * **Femoral ring:** This is the upper opening of the femoral canal, located medial to the femoral vein [1]. It is a site for potential femoral hernias, not the entry point of the artery. **High-Yield Clinical Pearls for NEET-PG:** * **Surface Marking:** The femoral artery's course is represented by the upper two-thirds of a line connecting the mid-inguinal point to the adductor tubercle (with the hip flexed and abducted). * **Relations:** At the inguinal ligament, the structures from lateral to medial are: **N**erve (Femoral), **A**rtery (Femoral), **V**ein (Femoral), **E**mpty space, **L**ymphatics (**NAVEL**). * **Termination:** The femoral artery ends by passing through the **adductor hiatus** (in the Adductor Magnus muscle) to become the **popliteal artery**. * **Clinical Use:** The mid-inguinal point is the preferred site for femoral artery puncture for arterial blood gas (ABG) analysis or cardiac catheterization.

Question 280: Nervi Furcalis is related to which spinal nerve root level?

A. L3
B. L4 (Correct Answer)
C. L5
D. L6

Explanation: **Explanation:** The **Nervi Furcalis** (or Furcal Nerve) is a specific spinal nerve that bridges the lumbar and sacral plexuses by dividing into two branches to contribute to both. In the majority of individuals (approx. 75-90%), the **L4 spinal nerve** acts as the Nervi Furcalis. It splits to join the lumbar plexus (contributing to the femoral and obturator nerves) and the sacral plexus (joining with L5 to form the lumbosacral trunk). **Analysis of Options:** * **Option B (L4) - Correct:** L4 is the most common level for the furcal nerve. Its identification is clinically significant in spinal surgery, as variations in its level can lead to atypical radiculopathy patterns. * **Option A (L3):** While the furcal nerve can occasionally be shifted cranially (pre-fixed plexus), L3 is rarely the primary furcal nerve. * **Option C (L5):** L5 typically forms the lumbosacral trunk with the descending branch of L4. If the plexus is "post-fixed," L5 may act as the furcal nerve, but this is less common than L4. * **Option D (L6):** An L6 nerve root only exists in individuals with a lumbarized S1 vertebra (a congenital variation). It is not the standard anatomical level for the Nervi Furcalis. **High-Yield Facts for NEET-PG:** * **Definition:** The nerve that provides the link between the lumbar and sacral plexuses. * **Clinical Significance:** The furcal nerve contains axons that contribute to multiple terminal nerves (Femoral, Obturator, and Sciatic). Consequently, a single-level disc prolapse at the L4 level can sometimes present with complex symptoms involving more than one dermatome or myotome. * **Plexus Types:** In a **Pre-fixed plexus**, the furcal nerve is L3; in a **Post-fixed plexus**, it is L5. In the **Normal** arrangement, it is L4.

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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

Lower Limb — MCQs

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