Lower Limb Practice Questions

Q: All of the following are contents of the adductor canal, EXCEPT?

Popliteal artery. The **Adductor Canal** (also known as Hunter’s canal or the Subsartorial canal) is an aponeurotic tunnel in the middle third of the thigh. It serves as a passage for structures moving from the femoral triangle to the popliteal fossa. ### **Why Option B is Correct** The **Popliteal artery** is the continuation of the femoral artery, but it only changes its name *after* it exits the adductor canal through the **adductor hiatus** (an opening in the Adductor magnus muscle). Therefore, the popliteal artery is a content of the popliteal fossa, not the adductor canal itself. ### **Why the Other Options are Incorrect** * **Femoral Artery (A):** This is the primary content of the canal. It enters at the apex of the femoral triangle and exits through the adductor hiatus. * **Nerve to Vastus Medialis (C):** This is the thickest muscular branch of the femoral nerve. it travels through the canal to supply the vastus medialis muscle. * **Saphenous Nerve (D):** This is the longest cutaneous branch of the femoral nerve. It travels through the canal but exits by piercing the fascial roof (vastoadductor membrane) to become superficial. ### **High-Yield NEET-PG Pearls** * **Boundaries:** Anterolateral (Vastus medialis), Posterior (Adductor longus and magnus), and Medial/Roof (Sartorius). * **Contents:** Femoral artery, Femoral vein, Saphenous nerve, and Nerve to vastus medialis. Note: The **Femoral nerve** itself is *not* a content; only its branches are. * **Clinical Significance:** The canal is a common site for an **Adductor Canal Block**, used for regional anesthesia in knee surgeries (e.g., TKR) because it provides sensory blockade via the saphenous nerve while sparing the motor function of the quadriceps (unlike a femoral nerve block).

Q: The condyles of the tibia provide attachment to which of the following?

Tibial collateral ligament. The **Tibial Collateral Ligament (TCL)**, also known as the Medial Collateral Ligament (MCL), is a broad, flat band located on the medial aspect of the knee joint. It is the correct answer because its **superior attachment** is to the medial condyle of the femur, while its **inferior attachment** is to the **medial condyle and the medial surface of the shaft of the tibia**. ### Analysis of Options: * **Tibial Collateral Ligament (Correct):** It consists of superficial and deep parts. The superficial part attaches to the medial tibial condyle and the shaft, while the deep part is firmly attached to the **medial meniscus**. * **Fibular Collateral Ligament (Incorrect):** This is a cord-like ligament on the lateral side. It attaches from the lateral femoral condyle to the **head of the fibula**, not the tibia. * **Ligamentum Patellae (Incorrect):** This is the continuation of the quadriceps tendon. It attaches to the **tibial tuberosity**, which is located on the anterior aspect of the tibia, distal to the condyles. * **Popliteus Muscle (Incorrect):** While the popliteus originates from the lateral femoral condyle, it inserts into the **posterior surface of the tibia** (above the soleal line), not specifically the condyles. ### High-Yield NEET-PG Pearls: * **Clinical Correlation:** Because the TCL is attached to the medial meniscus, an injury to the TCL often results in a concomitant tear of the medial meniscus (part of the **O'Donoghue’s Unhappy Triad**: ACL, TCL, and Medial Meniscus). * **Morphology:** The TCL represents the degenerated tendon of the **Adductor Magnus** muscle. * **Stability:** The TCL is the primary stabilizer against **valgus stress** (abduction) of the knee.

Q: An 80-year-old man presents with severe pain at his right hip and thigh, with difficulty in standing and reduced mobility. He reports a fall 2 days prior and a 3-year history of steroid use. An MRI of the right hip was performed. Which artery is most likely injured, leading to this condition?

Ascending branch of medial circumflex femoral artery. ***Ascending branch of medial circumflex femoral artery*** - This artery provides the **dominant blood supply** to the femoral head in adults through **ascending retinacular branches**, making it most susceptible to injury in **avascular necrosis (AVN)**. - **Steroid use** and **trauma** are major risk factors for AVN, causing interruption of this critical blood supply leading to **femoral head necrosis**. *Foveolar artery* - This artery only supplies a **small central portion** of the femoral head and is **not the dominant blood supply** in adults. - It runs through the **ligamentum teres** and contributes minimally to femoral head perfusion, making it unlikely to cause widespread AVN. *Descending branch of lateral circumflex femoral artery* - This vessel primarily supplies the **vastus lateralis muscle** and contributes to the **trochanteric region**, not the femoral head. - It does **not provide significant blood supply** to the femoral head, making it an unlikely cause of AVN. *Deep circumflex iliac artery* - This artery supplies the **iliac crest** and surrounding muscles, having **no involvement** in femoral head blood supply. - It runs along the **iliac crest** and is completely unrelated to the **hip joint** or femoral head perfusion.

Q: A 17-year-old boy was stabbed, resulting in the transection of the obturator nerve. Which of the following muscles is completely paralyzed?

Adductor longus. ### Explanation The **obturator nerve (L2–L4)** is the primary motor nerve of the medial compartment of the thigh. It supplies the adductor group of muscles, which are responsible for adducting the hip. **Why Adductor Longus is the Correct Answer:** The **Adductor longus** is supplied **solely** by the anterior division of the obturator nerve. Therefore, a complete transection of the obturator nerve results in its total paralysis. **Analysis of Incorrect Options:** * **Pectineus:** This is a "hybrid" or "composite" muscle. It is primarily supplied by the **femoral nerve**, though it occasionally receives a small branch from the obturator nerve. It would not be completely paralyzed. * **Adductor magnus:** This is also a hybrid muscle. Its adductor part is supplied by the **obturator nerve**, but its "hamstring part" (ischiocondylar portion) is supplied by the "tibial component of the sciatic nerve". * **Biceps femoris:** This is a muscle of the posterior compartment (hamstrings). The long head is supplied by the tibial part of the sciatic nerve, and the short head by the common peroneal part. It has no innervation from the obturator nerve. **High-Yield NEET-PG Pearls:** 1. **Hybrid Muscles of the Lower Limb:** * **Adductor Magnus:** Obturator + Sciatic (Tibial part) * **Pectineus:** Femoral + Obturator (Variable) * **Biceps Femoris:** Tibial + Common Peroneal (Sciatic nerve) 2. **Obturator Nerve Course:** It enters the thigh through the **obturator canal** and divides into anterior and posterior divisions around the **adductor brevis** muscle. 3. **Clinical Sign:** Injury to the obturator nerve leads to a significant loss of thigh adduction and a characteristic "swinging" gait.

Q: A 22-year-old man presents after a bicycle accident with a tibial fracture above the ankle. Physical examination reveals a severed tibial nerve on the posterior aspect of the tibia. Which of the following signs will most likely be present during physical examination?

Sensory loss on the sole of the foot. The **tibial nerve** is the larger terminal branch of the sciatic nerve (L4–S3). It descends through the popliteal fossa and passes deep to the flexor retinaculum at the ankle (tarsal tunnel). **1. Why the Correct Answer is Right:** The tibial nerve provides sensory innervation to the **entire sole of the foot** via its terminal branches: the medial and lateral plantar nerves. It also gives off the medial calcaneal branches to the heel. A severance of the nerve above the ankle interrupts these pathways, leading to anesthesia of the plantar surface. Additionally, it supplies the intrinsic muscles of the sole; however, sensory loss is a hallmark clinical finding in such injuries. **2. Why the Incorrect Options are Wrong:** * **Option A & D:** The **dorsum of the foot** and the **extensor digitorum brevis** are supplied by the **deep peroneal nerve** (a branch of the common peroneal nerve). Injury to the tibial nerve does not affect the anterior compartment of the leg or the dorsal intrinsic muscles. * **Option C:** **Foot drop** is caused by paralysis of the dorsiflexors (tibialis anterior), which are supplied by the **deep peroneal nerve**. Tibial nerve injury actually results in the inability to plantarflex (loss of "push-off") and a deformity known as **calcaneovalgus**. **3. NEET-PG High-Yield Pearls:** * **Tarsal Tunnel Syndrome:** Compression of the tibial nerve behind the medial malleolus, causing pain/paresthesia in the sole. * **Mnemonic for Tarsal Tunnel (Ant to Post):** **T**ibialis posterior, flexor **D**igitorum longus, posterior tibial **A**rtery, tibial **V**ein, tibial **N**erve, flexor **H**allucis longus (**T**om, **D**ick **A**nd **V**ery **N**ervous **H**arry). * **Reflex:** The tibial nerve mediates the **Achilles (Ankle) jerk (S1, S2)**.

Q: The base of the femoral triangle is formed by which anatomical structure?

Inguinal ligament. The **femoral triangle** is a subfascial space located in the upper one-third of the anterior thigh. To answer this question, one must visualize the triangle as an inverted pyramid where the "base" is superior and the "apex" points inferiorly. ### **Explanation of the Correct Answer** * **A. Inguinal Ligament:** This structure forms the **base** (superior boundary) of the femoral triangle [1]. It stretches from the anterior superior iliac spine (ASIS) to the pubic tubercle. It acts as a functional "retaining band" for structures passing from the pelvis to the lower limb. ### **Analysis of Incorrect Options** * **B. Medial border of sartorius:** This forms the **lateral boundary** of the triangle. * **C. Medial border of adductor longus:** This forms the **medial boundary**. Note: The apex of the triangle is where the medial border of the sartorius crosses the medial border of the adductor longus. * **D. Iliacus muscle:** Along with the psoas major, pectineus, and adductor longus, the iliacus forms the **floor** of the triangle, not its boundaries. ### **High-Yield Clinical Pearls for NEET-PG** 1. **Contents (Lateral to Medial):** Remember the mnemonic **NAVEL** (Femoral **N**erve, **A**rtery, **V**ein, **E**mpty space/Femoral canal, **L**ymphatics). 2. **Femoral Sheath:** This fascial envelope encloses the femoral artery, vein, and canal, but **excludes the femoral nerve**, which lies lateral to the sheath. 3. **Clinical Significance:** The femoral triangle is the site for femoral hernia (specifically the femoral canal) [1], femoral artery catheterization, and palpation of the femoral pulse (mid-inguinal point). 4. **Roof:** Formed by the skin, superficial fascia, and fascia lata (containing the cribriform fascia and the great saphenous vein opening).

Q: A 56-year-old male with advanced bladder carcinoma suffers from difficulty while walking. Muscle testing reveals weakened adductors of the right thigh. Which nerve is most likely being compressed by the tumor to result in walking difficulty?

Obturator. **Explanation:** The patient presents with weakness in the **adductors of the thigh**, which is the hallmark sign of **Obturator nerve** involvement. **1. Why Obturator Nerve is Correct:** The obturator nerve (L2–L4) originates from the lumbar plexus and descends through the pelvis. It passes along the lateral wall of the lesser pelvis, specifically near the **ovaries (in females)** and the **internal iliac lymph nodes**. In this case, advanced bladder carcinoma likely metastasized to the pelvic lymph nodes or directly invaded the lateral pelvic wall, compressing the nerve. The obturator nerve provides motor innervation to the **medial compartment of the thigh** (Adductor longus, brevis, magnus, and Gracilis). Weakness in these muscles leads to difficulty in stabilizing the pelvis and adducting the leg during the gait cycle. **2. Why Other Options are Incorrect:** * **Femoral Nerve (L2–L4):** Innervates the anterior compartment of the thigh (e.g., Quadriceps). Damage would cause loss of knee extension and hip flexion, not isolated adduction weakness. * **Common Fibular Nerve (L4–S2):** A branch of the sciatic nerve. Compression leads to "Foot Drop" due to paralysis of the anterior and lateral leg compartments. * **Tibial Nerve (L4–S3):** Innervates the posterior compartment of the leg. Damage results in an inability to plantarflex the foot. **3. High-Yield Clinical Pearls for NEET-PG:** * **Howship-Romberg Sign:** Pain/paresthesia on the medial aspect of the thigh due to obturator nerve compression (often seen in obturator hernias). * **Referred Pain:** Because the obturator nerve also supplies the hip and knee joints, pelvic pathology can sometimes present as isolated knee pain. * **Anatomy:** It is the only nerve of the lumbar plexus that emerges from the **medial** border of the psoas major muscle.

Question 1

An athlete is sitting on the edge of a table with knees flexed at 90 degrees. When the athlete fully extends their knee, what happens to the tibial tuberosity in relation to the patella?

Accepted Answer

Movement of the tibial tuberosity towards the lateral border of the patella

Answer

No change

Answer

Movement of the tibial tuberosity towards the medial border of the patella

Answer

Movement of the tibial tuberosity towards the center of the patella

Question 2

Identify the structure indicated by the arrow in the provided diagram.

Accepted Answer

Gracilis

Answer

Vastus lateralis

Answer

Rectus femoris

Answer

Vastus medialis

Question 3

All of the following are contents of the adductor canal, EXCEPT?

Accepted Answer

Popliteal artery

Answer

Femoral artery

Answer

Nerve to Vastus medialis

Answer

Saphenous nerve

Question 4

The condyles of the tibia provide attachment to which of the following?

Accepted Answer

Tibial collateral ligament

Answer

Fibular collateral ligament

Answer

Ligamentum patellae

Answer

Popliteus muscle

Question 5

An 80-year-old man presents with severe pain at his right hip and thigh, with difficulty in standing and reduced mobility. He reports a fall 2 days prior and a 3-year history of steroid use. An MRI of the right hip was performed. Which artery is most likely injured, leading to this condition?

Accepted Answer

Ascending branch of medial circumflex femoral artery

Answer

Foveolar artery

Answer

Descending branch of lateral circumflex femoral artery

Answer

Deep circumflex iliac artery

Question 6

A 17-year-old boy was stabbed, resulting in the transection of the obturator nerve. Which of the following muscles is completely paralyzed?

Accepted Answer

Adductor longus

Answer

Pectineus

Answer

Adductor magnus

Answer

Biceps femoris

Question 7

A 22-year-old man presents after a bicycle accident with a tibial fracture above the ankle. Physical examination reveals a severed tibial nerve on the posterior aspect of the tibia. Which of the following signs will most likely be present during physical examination?

Accepted Answer

Sensory loss on the sole of the foot

Answer

Sensory loss of the dorsum of the foot

Answer

Foot drop

Answer

Paralysis of the extensor digitorum brevis

Question 8

A 49-year-old man presents with a cold and pale foot. Physical examination reveals peripheral vascular disease, with duplex ultrasound studies indicating possible occlusion of his popliteal artery and an absent posterior tibial artery pulse. What is the most common location for palpation of the posterior tibial artery pulse?

Accepted Answer

Groove midway between the medial malleolus and the calcaneus

Answer

Lateral to the muscular belly of the abductor hallucis

Answer

Posteroinferior to the medial femoral condyle

Answer

Groove midway between the lateral malleolus and the calcaneus

Question 9

The base of the femoral triangle is formed by which anatomical structure?

Accepted Answer

Inguinal ligament

Answer

Medial border of sartorius muscle

Answer

Medial border of adductor longus muscle

Answer

Iliacus muscle

Question 10

A 56-year-old male with advanced bladder carcinoma suffers from difficulty while walking. Muscle testing reveals weakened adductors of the right thigh. Which nerve is most likely being compressed by the tumor to result in walking difficulty?

Accepted Answer

Obturator

Answer

Femoral

Answer

Common fibular (peroneal)

Answer

Tibial

Lower Limb — MCQs

Lower Limb — MCQs

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