Lower Limb Practice Questions

Q: The Trendelenburg sign is due to paralysis of which muscle?

Gluteus medius. The **Trendelenburg sign** is a clinical indicator of dysfunction in the **hip abductor mechanism**. The primary muscles responsible for stabilizing the pelvis during the stance phase of walking are the **Gluteus medius** and **Gluteus minimus**, both innervated by the **Superior Gluteal Nerve (L4-S1)**. When the weight is supported by one leg (the stance limb), the gluteus medius contracts to prevent the opposite side of the pelvis from sagging. If the gluteus medius is paralyzed or weak, the pelvis drops toward the unsupported (swinging) side. This is a "Positive Trendelenburg Sign." **Analysis of Options:** * **Gluteus medius (Correct):** It is the chief abductor of the hip. Its failure leads to pelvic instability during the gait cycle. * **Gluteus maximus:** This is the chief extensor of the hip (used for climbing stairs). Paralysis results in a "Gluteus Maximus Lurch" (backward trunk lean), not a pelvic drop. * **Piriformis:** This is a lateral rotator of the hip. While clinically significant due to its proximity to the sciatic nerve (Piriformis syndrome), it does not stabilize the pelvis in the coronal plane. * **Obturator externus:** This is a short lateral rotator of the thigh and does not contribute to hip abduction or pelvic stability during walking. **Clinical Pearls for NEET-PG:** 1. **Nerve Involved:** Damage to the **Superior Gluteal Nerve** (e.g., due to misplaced intramuscular injections in the gluteal region) is the most common cause of a positive Trendelenburg sign. 2. **Trendelenburg Gait:** To compensate for the pelvic drop, the patient tilts their trunk *towards* the affected side to shift the center of gravity; this is known as a **compensated Trendelenburg gait** or "Waddling gait" if bilateral. 3. **Mechanism:** The hip acts as a **Class 1 lever**, where the hip joint is the fulcrum.

Q: Which muscle of the foot is NOT supplied by the lateral plantar nerve?

1st Lumbrical. The innervation of the intrinsic muscles of the foot is a high-yield topic for NEET-PG, following a pattern similar to the hand. The muscles are supplied by the **medial and lateral plantar nerves**, which are terminal branches of the tibial nerve. ### **Why the 1st Lumbrical is the Correct Answer** The **1st Lumbrical** is supplied by the **Medial Plantar Nerve**. In the foot, the medial plantar nerve (analogous to the median nerve in the hand) supplies only four muscles, often remembered by the mnemonic **"LAFF"**: 1. **L** – 1st **L**umbrical 2. **A** – **A**bductor hallucis 3. **F** – **F**lexor hallucis brevis 4. **F** – **F**lexor digitorum brevis ### **Analysis of Incorrect Options** The **Lateral Plantar Nerve** (analogous to the ulnar nerve) supplies all other intrinsic muscles of the foot not covered by the medial plantar nerve: * **Abductor digiti minimi:** Supplied by the trunk/superficial branch of the lateral plantar nerve. * **Adductor hallucis:** Supplied by the deep branch of the lateral plantar nerve (similar to the adductor pollicis in the hand). * **Flexor digitorum accessorius (Quadratus Plantae):** Supplied by the main trunk of the lateral plantar nerve. ### **High-Yield Clinical Pearls for NEET-PG** * **Hand vs. Foot Analogy:** The Medial Plantar Nerve = Median Nerve; the Lateral Plantar Nerve = Ulnar Nerve. * **Baxter’s Nerve:** The first branch of the lateral plantar nerve (supplying Abductor digiti minimi) can become compressed, causing chronic heel pain mimicking plantar fasciitis. * **Sensory Distribution:** The medial plantar nerve supplies the medial 3.5 toes, while the lateral plantar nerve supplies the lateral 1.5 toes.

Q: What is the most anterior structure on the tibial plateau?

Anterior horn of the medial meniscus. The tibial plateau serves as the attachment site for several vital intra-articular structures. To master this high-yield topic, one must remember the specific **anteroposterior (front-to-back) sequence** of attachments on the intercondylar area of the tibia. ### **Anatomical Sequence (Mnemonic: Medical Licensure Always Leads Many People)** From anterior to posterior, the structures are attached in the following order: 1. **M**edial Meniscus (Anterior horn) — **Most Anterior** 2. **L**ateral Meniscus (Anterior horn) 3. **A**nterior Cruciate Ligament (ACL) 4. **L**ateral Meniscus (Posterior horn) 5. **M**edial Meniscus (Posterior horn) 6. **P**osterior Cruciate Ligament (PCL) — **Most Posterior** ### **Analysis of Options** * **Anterior horn of the medial meniscus (Correct):** This is the most anteriorly placed structure on the intercondylar area, sitting just in front of the intercondylar eminence. * **Anterior horn of the lateral meniscus (Incorrect):** This attaches just behind the medial meniscus and slightly lateral to the ACL's anterior attachment. * **Anterior cruciate ligament (Incorrect):** The ACL attaches behind both anterior horns of the menisci. * **Ligamentum patella (Incorrect):** While it is an anterior structure, it attaches to the **tibial tuberosity**, which is on the anterior surface of the tibia, not on the tibial plateau (superior surface). ### **Clinical Pearls for NEET-PG** * **Shape Difference:** The medial meniscus is **C-shaped** (larger and less mobile), while the lateral meniscus is **circular** (smaller and more mobile). * **The

Q: Which muscle, primarily acting as an evertor of the ankle, inserts into the medial cuneiform?

Peroneus longus. **Explanation:** The **Peroneus (Fibularis) longus** is the correct answer. It originates from the lateral surface of the fibula, travels behind the lateral malleolus, and crosses the sole of the foot diagonally to insert into the **base of the 1st metatarsal and the medial cuneiform**. Because it passes lateral to the axis of the subtalar joint, its primary action is **eversion** of the foot. It also assists in plantarflexion and helps maintain the transverse arch of the foot. **Analysis of Incorrect Options:** * **Peroneus brevis:** While it is also a primary evertor, it inserts into the **tuberosity of the 5th metatarsal**. It does not reach the medial side of the foot. * **Tibialis anterior:** This muscle does insert into the medial cuneiform (and 1st metatarsal), but it is a powerful **invertor** and dorsiflexor, not an evertor. * **Tibialis posterior:** This muscle is the principal **invertor** of the foot. It has a widespread insertion into the navicular tuberosity, all three cuneiforms, and the bases of the 2nd, 3rd, and 4th metatarsals. **High-Yield Clinical Pearls for NEET-PG:** * **The "Stirrup" of the Foot:** The Peroneus longus and Tibialis anterior both insert into the medial cuneiform and 1st metatarsal from opposite directions, forming a functional "stirrup" that supports the arches of the foot. * **Nerve Supply:** The Peroneus longus and brevis (Lateral compartment) are supplied by the **Superficial Peroneal Nerve**. * **Fracture Link:** A forced inversion injury can lead to an avulsion fracture of the 5th metatarsal base due to the pull of the Peroneus brevis tendon.

Q: Which muscle is supplied by the lumbar plexus?

Obturator externus. **Explanation:** The **Lumbar Plexus** (formed by the ventral rami of L1–L4) primarily supplies the muscles of the anterior and medial compartments of the thigh. 1. **Obturator Externus (Correct):** This muscle is located in the medial compartment of the thigh. It is supplied by the **Obturator nerve**, which is a major branch of the lumbar plexus (posterior divisions of L2, L3, and L4). Despite its name, it acts as a lateral rotator of the hip and is the only "short rotator" supplied by the lumbar plexus. **Why the other options are incorrect:** * **Obturator Internus:** Unlike the externus, this muscle is supplied by the **Nerve to Obturator Internus**, which arises from the **Sacral Plexus** (L5, S1, S2). * **Piriformis:** This is a key landmark muscle of the gluteal region supplied by direct branches from the **Sacral Plexus** (S1, S2). * **Gastrocnemius:** This is a muscle of the posterior compartment of the leg, supplied by the **Tibial nerve**, which is a terminal branch of the Sciatic nerve (Sacral Plexus, L4–S3). **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of Plexus":** Most muscles of the gluteal region and posterior thigh/leg are supplied by the **Sacral Plexus**, while the anterior and medial thigh are supplied by the **Lumbar Plexus**. * **Obturator Nerve:** It passes through the obturator canal. Referred pain from the hip joint (supplied by this nerve) is often felt on the medial aspect of the knee (Howship-Romberg sign). * **Psoas Major:** This is the only muscle supplied by the **direct branches** of the lumbar plexus (L1–L3) before the plexus divides into named nerves.

Q: Which of the following statements is true regarding the posterior cruciate ligament?

It prevents the posterior dislocation of the tibia.. The **Posterior Cruciate Ligament (PCL)** is a vital intracapsular stabilizer of the knee joint. It is thicker and stronger than the Anterior Cruciate Ligament (ACL). ### **Why Option C is Correct** The primary function of the PCL is to prevent **posterior displacement of the tibia** relative to the femur. It acts as the main stabilizer against posterior translation, especially when the knee is flexed. This is the anatomical basis for the "Posterior Drawer Test" used in clinical examinations. ### **Analysis of Incorrect Options** * **Option A:** The PCL attaches to the **medial femoral condyle** (specifically the anterolateral aspect). A common mnemonic to remember cruciate attachments is **LAMP**: **L**ateral condyle = **A**CL; **M**edial condyle = **P**CL. * **Option B:** While the PCL is intracapsular, it is **extrasynovial**. The synovial membrane reflects around the cruciate ligaments, excluding them from the synovial cavity. * **Option D:** The PCL becomes **taut (stretched) in full flexion**. In contrast, the ACL is taut in full extension. ### **High-Yield Clinical Pearls for NEET-PG** * **Mechanism of Injury:** Often caused by a direct blow to the proximal tibia in a flexed knee (e.g., hitting the dashboard in a car accident), known as a **"Dashboard Injury."** * **Clinical Sign:** Injury leads to a **"Sag Sign"** (posterior sagging of the tibia). * **Blood Supply:** Primarily from the **middle genicular artery**, a branch of the popliteal artery. * **Nerve Supply:** Tibial nerve (genicular branches).

Q: What is the name of the marked artery?

Posterior tibial artery. ***Posterior tibial artery*** - The **posterior tibial artery** runs in the **posterior compartment** of the leg and passes behind the **medial malleolus** at the ankle. - It divides into **medial plantar** and **lateral plantar arteries** after entering the foot, making it the main arterial supply to the plantar aspect. *Deep phalangeal artery* - This is not a standard anatomical term for a major artery in the lower limb vascular system. - The **digital arteries** supply the toes, but "deep phalangeal artery" is not a recognized major vessel in lower limb anatomy. *Lateral plantar artery* - This is a **terminal branch** of the posterior tibial artery that runs laterally in the foot. - It forms the **plantar arch** and supplies the lateral portion of the foot, but is not the main vessel behind the medial malleolus. *Medial plantar artery* - This is also a **terminal branch** of the posterior tibial artery that runs medially in the foot. - It supplies the **medial portion** of the foot and great toe area, but originates after the posterior tibial artery has already entered the foot.

Q: What is the nerve root value for the knee jerk reflex?

L2 L3 L4. The knee jerk reflex (patellar reflex) is a classic example of a **monosynaptic deep tendon reflex** [1]. When the patellar tendon is tapped, it stretches the quadriceps femoris muscle, stimulating muscle spindles. This sensory impulse travels via the **femoral nerve** to the spinal cord. ### Why L2, L3, L4 is Correct: The motor supply to the quadriceps femoris muscle is provided by the femoral nerve, which originates from the **ventral rami of L2, L3, and L4** spinal nerves. L3 and L4 are considered the primary segments responsible for this reflex, but the functional unit encompasses the L2-L4 distribution. ### Analysis of Incorrect Options: * **A. T12 L1 L2:** These roots primarily supply the iliopsoas (hip flexion) and the inguinal region. T12-L1 is associated with the Cremasteric reflex. * **C. L5 S1:** These are the root values for the **Ankle Jerk** (Achilles reflex) and are also involved in the Plantar response (Babinski sign). * **D. S2 S3:** These roots contribute to the nerve supply of the intrinsic foot muscles and are critical for bladder and bowel function (S2-S4). ### Clinical Pearls for NEET-PG: * **Nerve Involved:** Femoral Nerve. * **Muscle Involved:** Quadriceps femoris. * **Grading:** A pendular knee jerk (oscillating like a pendulum) is a classic sign of **Cerebellar lesions**. * **Westphal’s Sign:** The absence or decrease of the patellar reflex, often seen in Tabes Dorsalis or lower motor neuron lesions. * **Jendrassik Maneuver:** A distraction technique (clinching teeth/hooking fingers) used to accentuate a sluggish reflex by reducing descending inhibition.

Question 1

The Trendelenburg sign is due to paralysis of which muscle?

Accepted Answer

Gluteus medius

Answer

Gluteus maximus

Answer

Piriformis

Answer

Obturator externus

Question 2

Which muscle of the foot is NOT supplied by the lateral plantar nerve?

Accepted Answer

1st Lumbrical

Answer

Abductor digiti minimi

Answer

Adductor hallucis

Answer

Flexor digitorum accessorius

Question 3

What is the most anterior structure on the tibial plateau?

Accepted Answer

Anterior horn of the medial meniscus

Answer

Anterior horn of the lateral meniscus

Answer

Anterior cruciate ligament

Answer

Ligamentum patella

Question 4

Which muscle, primarily acting as an evertor of the ankle, inserts into the medial cuneiform?

Accepted Answer

Peroneus longus

Answer

Peroneus brevis

Answer

Tibialis anterior

Answer

Tibialis posterior

Question 5

Venous return to the heart during quiet standing is facilitated by all of the following factors EXCEPT?

Accepted Answer

Valves in deep fascia

Answer

Calf muscle contraction during standing

Answer

Valves in perforating veins

Answer

Gravitational increase in venous pressure

Question 6

Which muscle is supplied by the lumbar plexus?

Accepted Answer

Obturator externus

Answer

Obturator internus

Answer

Piriformis

Answer

Gastrocnemius

Question 7

Which of the following statements is true regarding the posterior cruciate ligament?

Accepted Answer

It prevents the posterior dislocation of the tibia.

Answer

It is attached to the lateral femoral condyle.

Answer

It is an intrasynovial structure.

Answer

It is relaxed in full flexion.

Question 8

What is the name of the marked artery?

Accepted Answer

Posterior tibial artery

Answer

Deep phalangeal artery

Answer

Lateral plantar artery

Answer

Medial plantar artery

Question 9

Which of the following is NOT TRUE about the Iliotibial tract?

Accepted Answer

The Gluteus minimus muscle inserts onto the Iliotibial tract.

Answer

The distal end of the Iliotibial tract is attached to Gerdy's tubercle.

Answer

The Tensor fascia lata muscle inserts onto the Iliotibial tract.

Answer

Contracture of the Iliotibial tract leads to flexion, external rotation, and posterior subluxation.

Question 10

What is the nerve root value for the knee jerk reflex?

Accepted Answer

L2 L3 L4

Answer

T12 L1 L2

Answer

L5 S1

Answer

S2 S3

Lower Limb — MCQs

Lower Limb — MCQs

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