Lower Limb Practice Questions

Q: Which of the following muscles is the extensor of the foot?

Peroneus longus. **Explanation:** In clinical anatomy, the terminology regarding foot movements can be confusing. While "extension" of the foot is often used synonymously with **plantarflexion** (moving the sole toward the ground), "flexion" refers to **dorsiflexion**. Among the options provided, **Peroneus (Fibularis) longus** is a primary evertor and a weak plantarflexor (extensor) of the foot. **Analysis of Options:** * **Peroneus longus (Correct):** Located in the lateral compartment of the leg, it is innervated by the superficial peroneal nerve. Its primary actions are eversion and **plantarflexion (extension)** of the foot at the ankle joint. * **Tibialis anterior (Incorrect):** This is the chief **dorsiflexor** (flexor) and invertor of the foot. It belongs to the anterior compartment. * **Flexor hallucis longus (Incorrect):** Located in the deep posterior compartment, its primary role is flexing the great toe, though it weakly assists in plantarflexion. * **Tibialis posterior (Incorrect):** This is the main invertor of the foot and also assists in plantarflexion. However, in the context of standard MCQ patterns for NEET-PG, when "extensor" is used to describe a muscle's primary functional group, the lateral or posterior compartment muscles are considered. **High-Yield Clinical Pearls for NEET-PG:** 1. **Nerve Supply Rule:** All muscles of the anterior compartment (dorsiflexors) are supplied by the **Deep Peroneal Nerve**. All muscles of the lateral compartment (evertors/plantarflexors) are supplied by the **Superficial Peroneal Nerve**. 2. **Foot Drop:** Injury to the Common Peroneal Nerve leads to loss of dorsiflexion (flexion) and eversion, resulting in "Foot Drop." 3. **The "Extensor" Paradox:** In the leg, the "Extensor Digitorum Longus" and "Extensor Hallucis Longus" actually perform **dorsiflexion**, which is functionally flexion. Always clarify if the question uses "extension" to mean plantarflexion.

Q: A football player has suffered severe trauma to the lateral part of the left leg just below the knee. He drags his left toe when he walks and cannot feel the dorsum of the foot. Which of the following functions or sensations will still be intact?

Cutaneous sensation of the medial leg. **Explanation:** The clinical presentation describes an injury to the **Common Peroneal (Fibular) Nerve**. This nerve is highly vulnerable to trauma as it winds around the **neck of the fibula**, just below the lateral aspect of the knee. **1. Why the Correct Answer is Right:** The **cutaneous sensation of the medial leg** is provided by the **Saphenous nerve**, which is a branch of the **Femoral nerve** (L2-L4). Since the injury is localized to the Common Peroneal nerve (L4-S2), the Saphenous nerve remains unaffected. Therefore, sensation on the medial side of the leg and foot remains intact. **2. Why Incorrect Options are Wrong:** * **Dorsiflexion (A):** This is performed by the muscles of the anterior compartment of the leg, supplied by the **Deep Peroneal nerve**. Injury to this nerve leads to "Foot Drop," explaining why the patient drags his toe. * **Eversion (B):** This is performed by the Peroneus longus and brevis in the lateral compartment, supplied by the **Superficial Peroneal nerve**. * **Sensation between the 1st and 2nd toes (D):** This specific area (the first dorsal web space) is the sensory territory of the **Deep Peroneal nerve**. **Clinical Pearls for NEET-PG:** * **Common Peroneal Nerve (CPN):** The most commonly injured nerve in the lower limb. * **Mnemonic for CPN branches:** **PED** (**P**eroneal **E**verts and **D**orsiflexes). If damaged, the foot is **DIP**ed (**D**orsiflexion and **I**nversion **P**aralyzed). * **Foot Drop:** Characterized by a "High Steppage Gait" to prevent the toes from dragging. * **Sensory Loss:** Superficial peroneal nerve supplies the majority of the dorsum of the foot; Deep peroneal nerve supplies only the first web space.

Q: The lateral cutaneous nerve of the thigh arises from which of the following?

Lumbar plexus. The **Lateral Cutaneous Nerve of the Thigh (LCNT)** is a purely sensory nerve that arises directly from the **Lumbar Plexus**, specifically from the posterior divisions of the ventral rami of **L2 and L3** spinal nerves. It emerges from the lateral border of the psoas major muscle, crosses the iliacus, and enters the thigh by passing posterior to the inguinal ligament, just medial to the anterior superior iliac spine (ASIS). **Analysis of Options:** * **Option B (Correct):** The LCNT is a direct branch of the lumbar plexus (L2, L3). It provides sensation to the skin of the anterior and lateral aspects of the thigh down to the knee. * **Option A (Femoral Nerve):** While the femoral nerve also arises from the lumbar plexus (L2–L4), the LCNT is a separate branch and does not originate from the femoral nerve itself. * **Option C (Obturator Nerve):** This nerve arises from the anterior divisions of L2–L4 and supplies the medial (adductor) compartment of the thigh. * **Option D (Sciatic Nerve):** This is the largest nerve of the body, arising from the sacral plexus (L4–S3), and supplies the posterior thigh and the entire leg and foot. **Clinical Pearls for NEET-PG:** * **Meralgia Paraesthetica:** This is a high-yield clinical condition caused by the compression of the LCNT as it passes under the inguinal ligament. It presents with tingling, numbness, or burning pain on the outer aspect of the thigh. Common causes include tight clothing (belts), obesity, and pregnancy. * **Root Value:** Remember the LCNT is **L2, L3**. In contrast, the Femoral and Obturator nerves are **L2, L3, L4**. * **Purely Sensory:** The LCNT carries no motor fibers; therefore, its injury results in sensory loss only, with no muscle weakness.

Q: What is the normal angle of the neck of the femur to its shaft?

125°. ### Explanation **1. Understanding the Correct Answer (B: 125°)** The **angle of inclination** (neck-shaft angle) is the angle formed between the long axis of the femoral neck and the long axis of the femoral shaft. In a normal adult, this angle typically ranges from **120° to 135°**, with **125°** being the most commonly cited average. This angle is crucial as it allows the femur to move freely away from the pelvis, facilitating limb mobility and providing a mechanical advantage to the hip abductors. **2. Analysis of Incorrect Options** * **A (110°):** This is significantly lower than normal. An angle less than 120° is termed **Coxa Vara**. * **C (170°):** This is excessively high. An angle greater than 135° is termed **Coxa Valga**. Note that in infants, the angle is naturally higher (around 150°) but decreases with weight-bearing. * **D (100°):** This represents a severe degree of Coxa Vara, often seen in pathological conditions like rickets or congenital deformities. **3. High-Yield Clinical Pearls for NEET-PG** * **Age Variation:** The angle is widest at birth (~150°) and gradually decreases to ~125° in adults due to the stresses of walking. It may further decrease in old age (predisposing to fractures). * **Coxa Vara ( 135°):** Leads to lengthening of the limb and increases the risk of hip dislocation. * **Angle of Anteversion:** Do not confuse the neck-shaft angle with the **angle of femoral torsion (anteversion)**, which is normally **15°** in adults (the angle the neck makes with the transverse axis of the femoral condyles).

Q: Damage to which of the following nerves leads to sensory loss on the adjacent sides of the great and second toes and impaired dorsiflexion of the foot?

Deep peroneal. ### Explanation The correct answer is **Deep peroneal nerve** (also known as the Deep Fibular nerve). #### 1. Why the Deep Peroneal Nerve is Correct The deep peroneal nerve is one of the two terminal branches of the common peroneal nerve. It is responsible for: * **Motor Supply:** It innervates the muscles of the anterior compartment of the leg (Tibialis anterior, Extensor digitorum longus, Extensor hallucis longus, and Peroneus tertius). These muscles are the primary **dorsiflexors** of the foot. Damage leads to "Foot Drop." * **Sensory Supply:** Its cutaneous distribution is very specific—it supplies only the **first interdigital cleft** (the adjacent sides of the great and second toes). #### 2. Why Other Options are Incorrect * **A. Superficial peroneal nerve:** It supplies the lateral compartment of the leg (fibularis longus/brevis) for eversion. Its sensory distribution covers the majority of the **dorsum of the foot**, excluding the first web space. * **B. Lateral plantar nerve:** A branch of the tibial nerve, it supplies the intrinsic muscles of the sole and the skin of the lateral 1.5 toes on the **plantar surface**, not the dorsum. * **C. Sural nerve:** Formed by branches of the tibial and common peroneal nerves, it provides purely sensory innervation to the **lateral border of the foot** and the little toe. #### 3. Clinical Pearls for NEET-PG * **Anterior Compartment Syndrome:** Increased pressure in the anterior compartment can compress the deep peroneal nerve, leading to the symptoms described. * **Foot Drop:** Characterized by a "high-stepping gait." Remember: **P**eroneal **D**orsiflexes and **E**verts (**PED**); **T**ibial **P**lantarflexes and **I**nverts (**TIP**). * **Nerve Compression:** The common peroneal nerve is the most commonly injured nerve in the lower limb due to its superficial course around the **neck of the fibula**.

Q: What is the primary action of the quadratus femoris muscle?

Lateral rotation. The **quadratus femoris** is a flat, quadrilateral muscle located in the gluteal region, belonging to the group of "short lateral rotators" of the hip. ### Why Lateral Rotation is Correct The muscle originates from the lateral border of the **ischial tuberosity** and inserts into the **quadrate tubercle** on the intertrochanteric crest of the femur. Due to its horizontal orientation and posterior position relative to the hip joint axis, its contraction pulls the greater trochanter posteriorly, resulting in the **lateral (external) rotation** of the thigh. It also assists in adduction. ### Why Other Options are Incorrect * **Extension:** This is primarily the function of the Gluteus maximus and the Hamstring group. * **Flexion:** This is the primary action of the Iliopsoas and Rectus femoris. * **Medial rotation:** This is performed by the Gluteus medius, Gluteus minimus (anterior fibers), and Tensor fasciae latae. ### NEET-PG High-Yield Pearls * **Nerve Supply:** It is supplied by the **Nerve to Quadratus Femoris** (L4, L5, S1), which also supplies the **Inferior gemellus**. * **Cruciate Anastomosis:** The quadratus femoris serves as the anatomical landmark for the cruciate anastomosis of the thigh; the transverse branch of the medial circumflex femoral artery runs across its superior border. * **The "Short Rotator" Group:** Includes the Piriformis, Obturator internus, Superior/Inferior gemelli, and Quadratus femoris. All are lateral rotators.

Q: Which muscle passes through the lesser sciatic foramen?

Obturator internus. The **Obturator internus** is the correct answer because it is the only muscle that utilizes the lesser sciatic foramen (LSF) as a functional pulley. It originates from the internal surface of the obturator membrane and the surrounding bony margins of the true pelvis. Its tendon then passes posteriorly, exits the pelvis through the **lesser sciatic foramen**, turns at a 90-degree angle, and inserts into the medial surface of the greater trochanter of the femur. **Analysis of Options:** * **Obturator externus (A):** Originates from the outer surface of the obturator membrane and passes *below* the acetabulum to reach the trochanteric fossa. It does not enter either sciatic foramen. * **Pectineus (C):** Located in the anterior compartment of the thigh. It originates from the pectineal line of the pubis and inserts into the femur; it has no anatomical relationship with the sciatic foramina. * **Piriformis (D):** This is the "key muscle" of the gluteal region, but it exits the pelvis through the **greater sciatic foramen**, not the lesser. **High-Yield Clinical Pearls for NEET-PG:** * **Structures passing through the Lesser Sciatic Foramen:** Remember the mnemonic **PIN**: **P**udendal nerve, **I**nternal pudendal vessels, and the Nerve to obturator internus (these enter the foramen), plus the **Obturator internus tendon** (which exits). * **The "Double Entry":** The Pudendal nerve and Internal pudendal vessels are unique because they exit the pelvis via the greater sciatic foramen and immediately re-enter via the lesser sciatic foramen to reach the perineum. * **The Lesser Sciatic Notch:** Acts as a trochlea (pulley) for the obturator internus tendon; a bursa is situated here to reduce friction.

Q: What is the nerve supply of the adductor magnus muscle?

Both tibial part of the sciatic nerve and obturator nerve. The **Adductor Magnus** is a unique muscle of the lower limb because it is a **hybrid (composite) muscle**, meaning it is derived from two different embryological compartments and thus possesses a dual nerve supply. ### Why Option C is Correct: The muscle consists of two distinct functional parts: 1. **Adductor (Pubofemoral) Part:** This part originates from the ischiopubic ramus and inserts into the gluteal tuberosity and linea aspera. It belongs to the medial compartment of the thigh and is supplied by the **posterior division of the obturator nerve (L2-L4)**. 2. **Hamstring (Ischiocondylar) Part:** This part originates from the ischial tuberosity and inserts into the adductor tubercle of the femur. Functionally and developmentally, it belongs to the posterior (hamstring) compartment and is supplied by the **tibial part of the sciatic nerve (L4-S3)**. ### Why Other Options are Incorrect: * **Option A & B:** These are incomplete. While both nerves do supply the muscle, selecting only one ignores the dual innervation characteristic that is frequently tested in anatomy. ### High-Yield Clinical Pearls for NEET-PG: * **Adductor Hiatus:** This is an opening between the two parts of the muscle that allows the femoral vessels to pass from the adductor canal into the popliteal fossa, becoming the popliteal vessels. * **Action:** The adductor part adducts and flexes the thigh, while the hamstring part extends the thigh. * **Other Hybrid Muscles (High-Yield):** * **Pectineus:** Femoral nerve and Obturator nerve. * **Biceps Femoris:** Tibial part (long head) and Common Peroneal part (short head) of the sciatic nerve. * **Digastric:** Nerve to mylohyoid (anterior belly) and Facial nerve (posterior belly).

Question 1

Which of the following muscles is the extensor of the foot?

Accepted Answer

Peroneus longus

Answer

Tibialis anterior

Answer

Flexor hallucis longus

Answer

Tibialis posterior

Question 2

A football player has suffered severe trauma to the lateral part of the left leg just below the knee. He drags his left toe when he walks and cannot feel the dorsum of the foot. Which of the following functions or sensations will still be intact?

Accepted Answer

Cutaneous sensation of the medial leg

Answer

Dorsiflexion

Answer

Eversion

Answer

Cutaneous sensation between the great toe and the second toe

Question 3

What is the primary action of the popliteus muscle?

Accepted Answer

Lateral rotation of the femur

Answer

Medial rotation of the femur

Answer

Locking of the knee

Answer

Extension of the knee

Question 4

The lateral cutaneous nerve of the thigh arises from which of the following?

Accepted Answer

Lumbar plexus

Answer

Femoral nerve

Answer

Obturator nerve

Answer

Sciatic nerve

Question 5

What is the normal angle of the neck of the femur to its shaft?

Accepted Answer

125°

Answer

110°

Answer

170°

Answer

100°

Question 6

Damage to which of the following nerves leads to sensory loss on the adjacent sides of the great and second toes and impaired dorsiflexion of the foot?

Accepted Answer

Deep peroneal

Answer

Superficial peroneal

Answer

Lateral plantar

Answer

Sural

Question 7

What is the primary action of the quadratus femoris muscle?

Accepted Answer

Lateral rotation

Answer

Extension

Answer

Flexion

Answer

Medial rotation

Question 8

Lateral meniscus is less prone to injury than medial meniscus because of the following reasons, except?

Accepted Answer

Lateral meniscus is opened outwards by the popliteus.

Answer

Lateral meniscus is less mobile than medial meniscus.

Answer

Lateral meniscus is more adapted to sustain injury.

Answer

Lateral meniscus undergoes less excursion during rotatory movement.

Question 9

Which muscle passes through the lesser sciatic foramen?

Accepted Answer

Obturator internus

Answer

Obturator externus

Answer

Pectineus

Answer

Piriformis

Question 10

What is the nerve supply of the adductor magnus muscle?

Accepted Answer

Both tibial part of the sciatic nerve and obturator nerve

Answer

Tibial part of the sciatic nerve

Answer

Obturator nerve

Answer

None of the above

Lower Limb — MCQs

Lower Limb — MCQs

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