Lower Limb Practice Questions

Q: Which of the following is NOT an action of the sartorius muscle?

Extension of the leg. The **Sartorius muscle**, known as the "Tailor's muscle," is the longest muscle in the human body. It is a superficial muscle of the anterior compartment of the thigh that crosses two joints: the hip and the knee. ### **Why "Extension of the leg" is the Correct Answer** The Sartorius originates from the **Anterior Superior Iliac Spine (ASIS)** and inserts into the upper part of the medial surface of the tibia (as part of the **Pes Anserinus**). Because it passes **posterior** to the transverse axis of the knee joint, its contraction results in **flexion of the leg**, not extension. Extension of the leg is the primary function of the Quadriceps Femoris group. ### **Analysis of Other Options** * **Flexion of the thigh:** As it crosses the hip joint anteriorly, it acts as a synergist in flexing the hip. * **Flexion of the leg:** Unlike the quadriceps, the sartorius pulls the tibia backward, causing knee flexion. * **Lateral rotation of the thigh:** Due to its oblique course across the thigh, it assists in rotating the femur laterally at the hip. ### **NEET-PG High-Yield Pearls** * **The "Tailor's Position":** The sartorius performs all actions required to sit cross-legged: Hip flexion, abduction, lateral rotation, and knee flexion. * **Pes Anserinus (Goose's Foot):** This is a common insertion point on the medial tibia for three muscles: **S**artorius (Femoral n.), **G**racilis (Obturator n.), and **S**emitendinosus (Tibial n.). *Mnemonic: "Say Grace before Tea."* * **Adductor Canal (Hunter’s Canal):** The sartorius forms the **roof** of this canal, which contains the femoral artery, femoral vein, and saphenous nerve. * **Nerve Supply:** It is supplied by the **Femoral Nerve (L2, L3)**.

Q: A 34-year-old power lifter has difficulty walking and a problem unlocking the knee joint to permit leg flexion. Which of the following muscles is most likely damaged?

Popliteus. ### Explanation **Correct Option: C. Popliteus** The **Popliteus** is known as the **"Key to the knee"** because of its essential role in initiating flexion from a fully extended position. * **The Mechanism:** When the knee is fully extended, it is "locked" in a position of maximum stability due to the medial rotation of the femur on the tibia. To initiate flexion, the knee must first be "unlocked." * **The Action:** The popliteus muscle accomplishes this by **laterally rotating the femur** on the fixed tibia (in a weight-bearing position, like a powerlifter standing) or medially rotating the tibia on the femur (in a non-weight-bearing position). This rotation relaxes the ligaments and allows flexion to proceed. --- ### Why the other options are incorrect: * **A. Biceps femoris:** This is a lateral hamstring muscle. While it is a flexor of the knee and a lateral rotator of the leg when the knee is flexed, it does not perform the initial "unlocking" required to start flexion from full extension. * **B. Gastrocnemius:** This muscle acts as a weak flexor of the knee and a strong plantarflexor of the ankle. It helps maintain the stability of the knee but does not have a rotatory component to unlock the joint. * **D. Semimembranosus:** This is a medial hamstring muscle. It assists in knee flexion and medial rotation of the leg when the knee is already flexed, but it is not the primary initiator of the unlocking mechanism. --- ### High-Yield Clinical Pearls for NEET-PG: * **Origin:** Lateral condyle of the femur (intracapsular but extrasynovial). * **Insertion:** Posterior surface of the tibia, above the soleal line. * **Innervation:** Tibial nerve (L4, L5, S1). * **The "Locking" Mechanism:** Occurs during the last 30° of extension; it is a passive movement (medial rotation of femur) that requires no muscle power. * **The "Unlocking" Mechanism:** An active process initiated by the **Popliteus**.

Q: Which structure passes deep to the medial malleolus?

Posterior tibial artery. The structures passing deep to the flexor retinaculum (behind the medial malleolus) are organized in a specific anteroposterior sequence. This is a classic high-yield topic for NEET-PG, often remembered by the mnemonic: **"Tom, Dick, And Very Nervous Harry."** 1. **T**ibialis posterior tendon (Most anterior) 2. **D**igitorum longus (Flexor digitorum longus tendon) 3. **A**rtery (Posterior tibial artery) 4. **V**ein (Posterior tibial vein) 5. **N**erve (Tibial nerve) 6. **H**arry (Flexor hallucis longus tendon - Most posterior/deep) **Explanation of Options:** * **A. Posterior tibial artery (Correct):** As per the mnemonic, the artery lies between the flexor digitorum longus and the tibial nerve behind the medial malleolus. * **B. Great saphenous vein:** This structure passes **anterior** to the medial malleolus, accompanied by the saphenous nerve. It is a superficial structure, not deep to the retinaculum. * **C. Tibialis anterior tendon:** This is a structure of the anterior compartment of the leg and passes anterior to the **ankle joint**, medial to the extensor hallucis longus. * **D. Peroneus tertius tendon:** This is also an anterior compartment muscle that inserts onto the base of the 5th metatarsal; it passes anterior to the **lateral malleolus**. **Clinical Pearls for NEET-PG:** * **Tarsal Tunnel Syndrome:** Compression of the tibial nerve as it passes deep to the flexor retinaculum. * **Pulsations:** The posterior tibial artery pulse is best felt midway between the medial malleolus and the medial tubercle of the calcaneus. * **Order:** Tibialis posterior is the first structure encountered immediately behind the medial malleolus and is the most commonly injured tendon in this region.

Q: Which is the most commonly injured nerve in the leg?

Common peroneal nerve. **Explanation:** The **Common Peroneal Nerve (CPN)**, also known as the common fibular nerve, is the most commonly injured nerve in the lower limb. The primary reason for its vulnerability is its **superficial anatomical course**. As it winds around the **neck of the fibula**, it lies directly against the bone, covered only by skin and fascia. This makes it highly susceptible to compression (e.g., tight casts, prolonged leg crossing) and direct trauma (e.g., fibular neck fractures). **Analysis of Options:** * **Common Peroneal Nerve (Correct):** Its exposed position at the fibular neck makes it the most frequent site of peripheral nerve entrapment in the leg, typically presenting as **foot drop** due to paralysis of the anterior and lateral compartment muscles. * **Femoral Nerve:** Located deep within the femoral triangle and protected by the inguinal ligament, it is rarely injured except during pelvic fractures or iatrogenic surgical trauma. * **Sciatic Nerve:** While it is the largest nerve, it is well-protected by the gluteus maximus and posterior thigh muscles. It is most commonly injured by posterior hip dislocations or misplaced intramuscular injections, but less frequently than the CPN. * **Tibial Nerve:** This nerve is deeply situated in the popliteal fossa and the posterior compartment of the leg. It is generally protected from external trauma, though it can be compressed in the tarsal tunnel. **Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Injury leads to **Foot Drop** (loss of dorsiflexion) and **Equinovarus** deformity. * **Sensory Loss:** Occurs on the dorsum of the foot and the lateral aspect of the leg. * **High-Yield Association:** Often associated with **Stryker's position** (lithotomy) or "Strawberry picker’s palsy" due to prolonged squatting.

Q: In preparing to isolate the proximal portion of the Femoral Artery, the vascular surgeon gently separated it from surrounding tissues. Posterior to the Femoral Sheath, what muscle forms the lateral portion of the floor of the Femoral Triangle?

Iliopsoas. ### Explanation The **Femoral Triangle** is a subfascial space in the upper third of the thigh. Understanding its boundaries and floor is high-yield for surgical anatomy and NEET-PG. **1. Why Iliopsoas is Correct:** The floor of the femoral triangle is gutter-shaped and formed by four muscles. From **lateral to medial**, these are: * **Iliopsoas:** Forms the lateral part of the floor. * **Pectineus:** Forms the medial part of the floor. * (In some texts, the Adductor Longus and Psoas Major are also listed as the most medial and lateral components respectively). Since the question asks for the muscle forming the **lateral portion** of the floor posterior to the femoral sheath, **Iliopsoas** is the correct anatomical landmark. [1] **2. Analysis of Incorrect Options:** * **Adductor Longus (A):** Forms the **medial boundary** of the femoral triangle and the most medial part of the floor. * **Sartorius (C):** Forms the **lateral boundary** of the femoral triangle. It does not form the floor. * **Pectineus (D):** Forms the **medial portion** of the floor. It lies medial to the iliopsoas. **3. Clinical Pearls & High-Yield Facts:** * **Mnemonic for Floor (Lateral to Medial):** "**I** **P**eat **A** lot" (**I**liopsoas, **P**ectineus, **A**dductor longus). * **Femoral Sheath Contents:** The sheath contains the femoral artery (lateral), femoral vein (intermediate), and femoral canal (medial). Note: The **Femoral Nerve** is NOT inside the femoral sheath; it lies lateral to it, resting on the iliopsoas muscle. [1] * **Boundaries:** Superior (Inguinal ligament), Lateral (Sartorius), Medial (Adductor longus). * **Apex:** Formed where the Sartorius crosses the Adductor Longus; it leads into the Adductor (Hunter’s) Canal.

Q: The obturator nerve enters the thigh by passing through which anatomical structure?

Obturator canal. **Explanation:** The **obturator nerve** (L2–L4) is a branch of the lumbar plexus that descends through the psoas major muscle and enters the pelvis. It exits the pelvis to enter the medial compartment of the thigh via the **obturator canal**. This canal is a small opening in the superior part of the obturator membrane, which covers the obturator foramen. Upon entering the thigh, the nerve divides into anterior and posterior divisions, providing motor supply to the adductor muscles and sensory innervation to the medial thigh. **Analysis of Incorrect Options:** * **Adductor canal (Hunter’s canal):** This is a fascial tunnel in the middle third of the thigh. It contains the femoral artery, femoral vein, and the saphenous nerve, but not the obturator nerve. * **Superficial inguinal ring:** This is an opening in the external oblique aponeurosis. It serves as the exit for the spermatic cord (in males) or the round ligament (in females) and the ilioinguinal nerve. * **Femoral canal:** This is the most medial compartment of the femoral sheath. It contains lymphatic vessels and Cloquet’s node; it is a common site for femoral hernias but does not transmit the obturator nerve. **High-Yield Clinical Pearls for NEET-PG:** * **Howship-Romberg Sign:** Pain or paresthesia on the medial aspect of the thigh due to compression of the obturator nerve (often by an obturator hernia). * **Referred Pain:** Pathology in the hip joint can cause referred pain to the knee because the obturator nerve supplies both joints. * **Adductor reflex:** The obturator nerve is the efferent and afferent limb for the adductor reflex (L2-L4).

Q: What is the main action of the Gemellus muscle?

Lateral rotation of the thigh. **Explanation:** The **Gemellus muscles** (Superior and Inferior) belong to the group of **short lateral rotators** of the hip. They are located in the gluteal region, situated superior and inferior to the tendon of the Obturator internus. **1. Why Option B is Correct:** The Gemelli muscles originate from the ischial spine (Superior) and ischial tuberosity (Inferior) and insert into the medial surface of the greater trochanter of the femur. Due to their posterior position relative to the hip joint axis, their contraction pulls the greater trochanter posteriorly, resulting in the **lateral (external) rotation** of the extended thigh. They also help stabilize the femoral head in the acetabulum. **2. Why Other Options are Incorrect:** * **Option A (Medial rotation):** This is primarily performed by the Gluteus medius, Gluteus minimus, and Tensor fasciae latae. * **Option C (Flexion):** The primary hip flexors are the Iliopsoas, Pectineus, and Rectus femoris. * **Option D (Extension):** Hip extension is the main action of the Gluteus maximus and the Hamstring muscles. **3. High-Yield NEET-PG Clinical Pearls:** * **Innervation:** The Superior Gemellus is supplied by the **nerve to obturator internus** (L5, S1), while the Inferior Gemellus is supplied by the **nerve to quadratus femoris** (L4, L5, S1). * **The "Triceps Coxae":** The Superior Gemellus, Obturator Internus, and Inferior Gemellus are often referred to as the *Triceps Coxae* because they share a common insertion. * **Surgical Landmark:** These muscles are vital landmarks during the posterior approach to the hip joint; the sciatic nerve lies superficial to them.

Q: The dorsalis pedis artery is the continuation of which artery?

Anterior tibial artery. ### Explanation **Correct Option: A. Anterior Tibial Artery** The **dorsalis pedis artery** is the direct continuation of the **anterior tibial artery**. This transition occurs at the level of the **ankle joint**, specifically midway between the two malleoli. It runs along the dorsum of the foot to the proximal end of the first intermetatarsal space, where it terminates by dividing into the first dorsal metatarsal artery and the deep plantar artery (which completes the plantar arch). **Analysis of Incorrect Options:** * **B. Posterior Tibial Artery:** This artery passes behind the medial malleolus and terminates by dividing into the medial and lateral plantar arteries on the sole of the foot. * **C. Popliteal Artery:** This is the parent vessel located in the popliteal fossa. It terminates at the lower border of the popliteus muscle by dividing into the anterior and posterior tibial arteries. * **D. Lateral Tarsal Artery:** This is a **branch** of the dorsalis pedis artery, not its origin. It helps supply the tarsal bones and joints. **Clinical Pearls for NEET-PG:** * **Palpation:** The dorsalis pedis pulse is clinically palpated on the dorsum of the foot, just lateral to the tendon of the **Extensor Hallucis Longus (EHL)**. * **Surface Marking:** It is represented by a line joining the midpoint between the malleoli to the proximal end of the first intermetatarsal space. * **Vascular Significance:** Absence of this pulse may indicate peripheral arterial disease (PAD) or Buerger’s disease. However, note that the pulse is congenitally absent in approximately 10% of the population. * **Anastomosis:** The deep plantar branch of the dorsalis pedis joins the lateral plantar artery to form the **Deep Plantar Arch**.

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

The first web space. **Explanation:** The **deep peroneal nerve (DPN)**, a terminal branch of the common peroneal nerve, primarily serves the anterior compartment of the leg. While its function is predominantly motor (innervating the dorsiflexors of the foot and extensors of the toes), its **sensory distribution is highly localized and specific.** 1. **Why Option C is Correct:** After passing deep to the extensor retinaculum, the DPN terminates by supplying the skin of the **first interdigital cleft (the first web space)** and the adjacent sides of the great toe and second toe. This is a high-yield anatomical landmark frequently tested in exams. 2. **Analysis of Incorrect Options:** * **Option A (Anterolateral dorsum of the foot):** This area is primarily supplied by the **superficial peroneal nerve**, which provides sensory innervation to the majority of the dorsal surface of the foot (except the first web space and the lateral edge). * **Option B (Lateral aspect of the leg):** This is supplied by the **lateral sural cutaneous nerve** (a branch of the common peroneal nerve). * **Option D (The fifth web space):** The lateral border of the foot and the fifth digit area are supplied by the **sural nerve**. **Clinical Pearls for NEET-PG:** * **Anterior Compartment Syndrome:** Increased pressure in the anterior compartment can compress the DPN, leading to "foot drop" (motor loss) and sensory loss specifically in the **first web space**. * **Ski Boot Neuropathy:** Compression of the DPN under the extensor retinaculum causes pain and paresthesia in the first web space. * **Mnemonic:** Remember **"Deep = Digits"** (specifically the first two) and **"Superficial = Surface"** (most of the dorsal surface).

Question 1

Which of the following is NOT an action of the sartorius muscle?

Accepted Answer

Extension of the leg

Answer

Flexion of the thigh

Answer

Flexion of the leg

Answer

Lateral rotation of the thigh

Question 2

A 34-year-old power lifter has difficulty walking and a problem unlocking the knee joint to permit leg flexion. Which of the following muscles is most likely damaged?

Accepted Answer

Popliteus

Answer

Biceps femoris

Answer

Gastrocnemius

Answer

Semimembranosus

Question 3

Which structure passes deep to the medial malleolus?

Accepted Answer

Posterior tibial artery

Answer

Great saphenous vein

Answer

Tibialis anterior tendon

Answer

Peroneus tertius tendon

Question 4

Which is the most commonly injured nerve in the leg?

Accepted Answer

Common peroneal nerve

Answer

Femoral nerve

Answer

Sciatic nerve

Answer

Tibial nerve

Question 5

In preparing to isolate the proximal portion of the Femoral Artery, the vascular surgeon gently separated it from surrounding tissues. Posterior to the Femoral Sheath, what muscle forms the lateral portion of the floor of the Femoral Triangle?

Accepted Answer

Iliopsoas

Answer

Adductor Longus

Answer

Sartorius

Answer

Pectineus

Question 6

The obturator nerve enters the thigh by passing through which anatomical structure?

Accepted Answer

Obturator canal

Answer

Adductor canal

Answer

Superficial inguinal ring

Answer

Femoral canal

Question 7

What is the main action of the Gemellus muscle?

Accepted Answer

Lateral rotation of the thigh

Answer

Medial rotation of the thigh

Answer

Flexion of the hip

Answer

Extension of the hip

Question 8

The dorsalis pedis artery is the continuation of which artery?

Accepted Answer

Anterior tibial artery

Answer

Posterior tibial artery

Answer

Popliteal artery

Answer

Lateral tarsal artery

Question 9

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

Accepted Answer

The first web space

Answer

Anterolateral dorsum of the foot

Answer

Lateral aspect of the leg

Answer

The fifth web space

Question 10

Which of the following statements about the menisci is not true?

Accepted Answer

The menisci are made up of Collagen Type I.

Answer

The lateral meniscus is more mobile than the medial meniscus.

Answer

The lateral meniscus covers more area of the tibial articular surface than the medial meniscus.

Answer

The menisci are composed of around 75% water.

Lower Limb — MCQs

Lower Limb — MCQs

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