Lower Limb Practice Questions

Q: Which nerve supplies the anterior compartment of the leg?

Deep peroneal nerve. The anterior compartment of the leg is primarily responsible for **dorsiflexion** of the foot and **extension** of the toes. ### Why the Deep Peroneal Nerve is Correct The **Deep Peroneal (Fibular) Nerve** is one of the two terminal branches of the Common Peroneal nerve. It enters the anterior compartment by piercing the anterior intermuscular septum. It provides motor supply to all four muscles of this compartment: 1. Tibialis anterior 2. Extensor digitorum longus 3. Extensor hallucis longus 4. Peroneus tertius Sensory-wise, it supplies only the small area of skin in the **first web space** of the foot. ### Why the Other Options are Incorrect * **A. Superficial Peroneal Nerve:** This nerve supplies the **lateral compartment** of the leg (Peroneus longus and brevis) and provides sensory innervation to the majority of the dorsum of the foot. * **C. Saphenous Nerve:** This is a purely sensory branch of the femoral nerve. it supplies the skin on the medial side of the leg and foot. * **D. Sural Nerve:** Formed by branches of the tibial and common peroneal nerves, it is a purely sensory nerve supplying the skin of the lateral and posterior part of the lower third of the leg and the lateral border of the foot. ### High-Yield Clinical Pearls for NEET-PG * **Foot Drop:** Injury to the Common Peroneal nerve (at the neck of the fibula) or the Deep Peroneal nerve leads to "Foot Drop" due to paralysis of the anterior compartment muscles. * **Anterior Compartment Syndrome:** Increased pressure in this tight fascial space can compress the Deep Peroneal nerve, leading to weakness in dorsiflexion and sensory loss in the first web space. * **The "Nerve of the Anterior Compartment":** Deep Peroneal Nerve. * **The "Nerve of the Lateral Compartment":** Superficial Peroneal Nerve.

Q: A 21-year-old man was involved in a motorcycle accident, resulting in destruction of the groove in the lower surface of the cuboid bone. Which of the following muscle tendons is most likely damaged?

Peroneus longus. The correct answer is **Peroneus longus (Fibularis longus)**. **Why it is correct:** The cuboid bone features a distinct oblique groove on its plantar (lower) surface. This groove is specifically designed to house the tendon of the **peroneus longus** muscle as it traverses the sole of the foot from the lateral side to its insertion on the base of the first metatarsal and the medial cuneiform. The groove is often converted into a tunnel by the long plantar ligament, providing a smooth pathway for the tendon. **Why other options are incorrect:** * **Flexor hallucis longus:** This tendon passes through a groove on the posterior surface of the **talus** and under the **sustentaculum tali** of the calcaneus, not the cuboid. * **Peroneus brevis:** This muscle inserts directly onto the tubercle at the base of the **5th metatarsal**. It does not cross the plantar surface of the cuboid. * **Tibialis anterior:** This muscle is located in the anterior compartment of the leg and inserts onto the medial cuneiform and the base of the first metatarsal from the **medial/dorsal** aspect, staying far from the cuboid. **NEET-PG High-Yield Pearls:** * **The Os Peroneum:** A sesamoid bone is frequently found within the peroneus longus tendon where it arches around the cuboid; this can be mistaken for a fracture on X-rays. * **Arch Support:** The peroneus longus and tibialis posterior are often called the "stirrup" of the foot because they support the longitudinal and transverse arches. * **Nerve Supply:** All peroneal (fibular) muscles are supplied by the **superficial peroneal nerve**, except for the Peroneus tertius (deep peroneal nerve).

Q: Inguinal lymph node enlargement is seen in which of the following conditions?

Malignant melanoma of the foot. **Explanation:** The lymphatic drainage of the body follows specific anatomical pathways, which is a high-yield concept for NEET-PG. **1. Why Option B is Correct:** The skin of the lower limb (including the foot), the trunk below the level of the umbilicus, the perineum, and the anal canal (below the pectinate line) all drain into the **superficial inguinal lymph nodes**. Therefore, a malignant melanoma of the foot will metastasize primarily to the inguinal nodes. **2. Why Other Options are Incorrect:** * **A. Seminoma of Testis:** The testes develop in the lumbar region and descend into the scrotum, carrying their lymphatic drainage with them. They drain directly into the **Para-aortic (Pre-aortic) lymph nodes** at the level of L2. *Note: Inguinal nodes are only involved if the scrotal skin is invaded.* * **C. Carcinoma of the Cervix:** The cervix primarily drains into the **Internal iliac** and **External iliac lymph nodes**, and subsequently to the common iliac nodes. It does not drain into the inguinal nodes. **Clinical Pearls for NEET-PG:** * **The "Water-Shed" Line:** The umbilicus acts as a watershed; skin above drains to axillary nodes, skin below drains to superficial inguinal nodes. * **Exceptions to Inguinal Drainage:** Two structures in the pelvic/perineal region do **not** drain to inguinal nodes: the **Testis** (Para-aortic) and the **Glans Penis/Clitoris** (Deep inguinal/Cloquet’s node). * **Cloquet’s Node:** The highest deep inguinal node, located in the femoral canal; it is a key landmark in femoral hernia surgery and pelvic malignancies.

Q: Which ossification center appears first?

Lower end of femur. The correct answer is **B. Lower end of femur.** ### Explanation The ossification of the femur follows a specific chronological sequence. The **lower end of the femur** is unique because its secondary ossification center appears at the **9th month of intrauterine life (36-40 weeks)**. This makes it one of the few secondary centers present at birth, serving as a crucial medico-legal indicator of fetal maturity (viability) [1]. ### Analysis of Options * **Lower end of femur (Correct):** Appears at the end of the 9th month of gestation. It is the first secondary ossification center of the femur to appear. * **Head of femur (Incorrect):** This center appears during the **6th month of postnatal life** (approx. 6 months after birth). * **Greater trochanter (Incorrect):** This center appears much later, typically between **4 to 5 years** of age. * **Upper end of femur (Incorrect):** This is a general term encompassing the head, greater, and lesser trochanters. Since the head appears at 6 months and the trochanters even later, it cannot be the first center. ### NEET-PG High-Yield Pearls 1. **Rule of Ossification at Birth:** The three secondary centers usually present at birth are the **Lower end of the femur**, **Upper end of the tibia**, and sometimes the **Head of the humerus**. 2. **Medico-legal Significance:** The presence of the lower femoral epiphysis in a newborn indicates that the fetus was full-term (at least 38 weeks). 3. **Growth Contribution:** The lower end of the femur is the "growing end" of the bone (it follows the rule: *to the elbow I go, from the knee I flee*). It accounts for approximately 70% of the total femoral length. 4. **Fusion:** While it appears first, it fuses last (around 18–20 years).

Q: A 24-year-old man is admitted to the emergency department after a car collision. Radiographic examination reveals a fracture at the junction of the middle and lower thirds of the femur. An MRI examination provides evidence that the popliteal vessels were injured when the distal fragment of the fracture was pulled posteriorly. Which of the following muscles is most likely to displace the distal fracture fragment?

Gastrocnemius. **Explanation:** **1. Why Gastrocnemius is Correct:** In fractures involving the distal third of the femur (supracondylar fractures), the displacement of fragments is determined by the pull of attached muscles. The **gastrocnemius** muscle originates from the medial and lateral condyles of the femur. When a fracture occurs just above these condyles, the powerful pull of the gastrocnemius tips the distal fragment **posteriorly** (backward) into the popliteal fossa. This is clinically critical because the popliteal artery and vein lie directly behind the femur and can be compressed or lacerated by this sharp bony fragment, leading to limb-threatening ischemia. **2. Why Other Options are Incorrect:** * **Soleus:** This muscle originates from the tibia and fibula, not the femur. Therefore, it has no direct action on the femoral fracture fragments. * **Semitendinosus & Gracilis:** These are "hamstring" and adductor group muscles, respectively. While they may cause some proximal displacement (shortening of the limb) by pulling the distal fragment upward, they do not cause the specific posterior rotation/angulation characteristic of this injury. **3. High-Yield Clinical Pearls for NEET-PG:** * **Proximal Fragment Displacement:** In femoral shaft fractures, the proximal fragment is typically flexed and abducted due to the pull of the **Iliopsoas** and **Gluteus medius/minimus**. * **Popliteal Artery:** It is the deepest structure in the popliteal fossa, making it the most vulnerable vessel in supracondylar fractures and posterior knee dislocations. * **Nerve Involvement:** While the artery is at risk from the bone fragment, the **Tibial nerve** is the most superficial structure in the fossa and is more prone to compression from hematomas or external trauma. * **Rule of Thumb:** Always check distal pulses (Dorsalis pedis and Posterior tibial) in any distal femur injury.

Q: A patient presents with loss of extension at the knee joint and decreased sensation over the anterior aspect of the thigh. Which nerve is likely damaged?

Femoral. **Explanation:** The clinical presentation points directly to a lesion of the **Femoral Nerve (L2–L4)**. **1. Why Femoral Nerve is correct:** * **Motor Function:** The femoral nerve innervates the anterior compartment of the thigh, primarily the **Quadriceps femoris** (rectus femoris, vastus lateralis, medialis, and intermedius). The quadriceps are the sole extensors of the knee; thus, nerve damage leads to loss of extension. * **Sensory Function:** It provides cutaneous innervation to the **anterior thigh** via the anterior cutaneous branches and the medial leg via the saphenous nerve. **2. Why other options are incorrect:** * **Obturator Nerve:** Innervates the medial compartment (adductors). Damage results in weakness of thigh adduction, not knee extension. * **Common Peroneal Nerve:** A branch of the sciatic nerve that innervates the anterior and lateral compartments of the leg. Damage leads to "foot drop" (loss of dorsiflexion) and sensory loss on the lateral leg/dorsum of the foot. * **Tibial Nerve:** Innervates the posterior compartment of the thigh (hamstrings) and leg. Damage results in loss of plantar flexion and impaired knee flexion. **3. Clinical Pearls for NEET-PG:** * **Root Value:** L2, L3, L4 (Posterior divisions of ventral rami). * **Injury Site:** Often damaged during pelvic surgeries, femoral artery catheterization, or by psoas abscesses. * **Patellar Reflex:** Femoral nerve damage results in the loss of the **knee-jerk reflex (L3-L4)**. * **Saphenous Nerve:** The longest purely sensory branch of the femoral nerve; it is frequently tested regarding its course alongside the great saphenous vein.

Q: Which of the following muscles supports the Spring ligament?

Tibialis posterior. **Explanation:** The **Spring ligament** (Plantar calcaneonavicular ligament) is a thick, fibrocartilaginous band that connects the sustentaculum tali of the calcaneus to the navicular bone. Its primary function is to support the head of the talus and maintain the **medial longitudinal arch** of the foot. **1. Why Tibialis Posterior is correct:** The **Tibialis posterior** muscle is the most important dynamic stabilizer of the medial longitudinal arch. Its tendon passes immediately inferior to the Spring ligament, acting as a "sling" or physical floor that reinforces the ligament. When the muscle contracts, it tenses the ligament and elevates the talar head, preventing the arch from collapsing. **2. Why other options are incorrect:** * **Peroneus longus:** This muscle supports the **lateral** longitudinal arch and the **transverse** arch. It crosses the sole from the lateral side to insert into the first metatarsal and medial cuneiform, but it does not provide direct structural support to the Spring ligament. * **Abductor hallucis:** While it provides some intrinsic support to the medial arch, it is a superficial muscle of the sole and does not have a direct anatomical relationship with the Spring ligament. **Clinical Pearls for NEET-PG:** * **Flat Foot (Pes Planus):** Dysfunction or rupture of the Tibialis posterior tendon is the most common cause of acquired flat foot in adults, as the Spring ligament loses its primary muscular support and eventually stretches. * **The "Spring":** The ligament is called "spring" because it contains elastic fibers that allow it to yield under weight and then recoil, aiding in the propulsion phase of walking. * **Anatomy:** The superior surface of the Spring ligament is lined with synovial membrane and forms part of the articular cavity for the head of the talus.

Q: The distal part of the lesser saphenous vein was mobilized for grafting. Following the operation, the patient complained of numbness on the distal lateral side of the leg and the lateral side of the foot. What nerve was likely damaged during the operation?

Sural. **Explanation:** The **Sural nerve** is the correct answer because of its intimate anatomical relationship with the **small (lesser) saphenous vein (SSV)**. 1. **Anatomical Relationship:** The SSV originates from the lateral end of the dorsal venous arch of the foot. It ascends behind the lateral malleolus and runs along the midline of the calf to drain into the popliteal vein. Throughout its course in the leg, the **Sural nerve** (a branch derived from the tibial and common fibular nerves) runs immediately adjacent to the SSV. 2. **Clinical Presentation:** The Sural nerve provides sensory innervation to the **skin of the distal posterolateral leg and the lateral border of the foot** up to the tip of the little toe. Damage during mobilization of the distal SSV leads to numbness in exactly these areas. **Why other options are incorrect:** * **Deep fibular nerve:** Supplies the web space between the first and second toes; it is located in the anterior compartment of the leg. * **Posterior femoral cutaneous nerve:** Supplies the skin of the posterior thigh and popliteal fossa, ending much higher than the distal leg. * **Saphenous nerve:** This nerve accompanies the **Great (Long) saphenous vein** on the medial side of the leg and foot. Injury would cause numbness on the medial malleolus and medial arch. **High-Yield NEET-PG Pearls:** * **Great Saphenous Vein (GSV):** Accompanied by the **Saphenous nerve** (anterior to medial malleolus). * **Small Saphenous Vein (SSV):** Accompanied by the **Sural nerve** (behind lateral malleolus). * The Sural nerve is frequently used as a donor for **nerve grafting** because its loss results in only a minor sensory deficit [1].

Question 1

Which nerve supplies the anterior compartment of the leg?

Accepted Answer

Deep peroneal nerve

Answer

Superficial peroneal nerve

Answer

Saphenous nerve

Answer

Sural nerve

Question 2

A 21-year-old man was involved in a motorcycle accident, resulting in destruction of the groove in the lower surface of the cuboid bone. Which of the following muscle tendons is most likely damaged?

Accepted Answer

Peroneus longus

Answer

Flexor hallucis longus

Answer

Peroneus brevis

Answer

Tibialis anterior

Question 3

Inguinal lymph node enlargement is seen in which of the following conditions?

Accepted Answer

Malignant melanoma of the foot

Answer

Seminoma of testis

Answer

Carcinoma of the cervix

Answer

None of the above

Question 4

Which ossification center appears first?

Accepted Answer

Lower end of femur

Answer

Upper end of femur

Answer

Greater trochanter

Answer

Head

Question 5

A 24-year-old man is admitted to the emergency department after a car collision. Radiographic examination reveals a fracture at the junction of the middle and lower thirds of the femur. An MRI examination provides evidence that the popliteal vessels were injured when the distal fragment of the fracture was pulled posteriorly. Which of the following muscles is most likely to displace the distal fracture fragment?

Accepted Answer

Gastrocnemius

Answer

Soleus

Answer

Semitendinosus

Answer

Gracilis

Question 6

A patient presents with loss of extension at the knee joint and decreased sensation over the anterior aspect of the thigh. Which nerve is likely damaged?

Accepted Answer

Femoral

Answer

Obturator

Answer

Common peroneal

Answer

Tibial

Question 7

Which of the following muscles supports the Spring ligament?

Accepted Answer

Tibialis posterior

Answer

Peroneus longus

Answer

Abductor hallucis

Answer

All of the above

Question 8

The distal part of the lesser saphenous vein was mobilized for grafting. Following the operation, the patient complained of numbness on the distal lateral side of the leg and the lateral side of the foot. What nerve was likely damaged during the operation?

Accepted Answer

Sural

Answer

Deep fibular (peroneal)

Answer

Posterior femoral cutaneous

Answer

Saphenous

Question 9

Which statement best describes the medial compartment of the thigh?

Accepted Answer

Adductor magnus, longus, and brevis insert onto the linea aspera.

Answer

All the muscles of the medial compartment are innervated by the obturator nerve.

Answer

All the muscles of the medial compartment take origin from the ischium.

Answer

The obturator nerve is split into anterior and posterior divisions by adductor longus.

Question 10

Which of the following are features of common peroneal nerve injury?

Accepted Answer

Foot drop, Loss of extension of great toe, and Seen in fibular neck fracture

Answer

Inversion inability, Loss of sensation of sole, and Foot drop

Answer

Loss of sensation of sole, Foot drop, and Loss of extension of great toe

Answer

Inversion inability, Loss of sensation of sole, Foot drop, Loss of extension of great toe, and Seen in fibular neck fracture

Lower Limb — MCQs

Lower Limb — MCQs

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