Lower Limb Practice Questions

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].

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 Popliteal Artery is the Correct Answer: The **Femoral artery** enters the adductor canal at its apex. However, it only becomes the **Popliteal artery** after it exits the 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. ### Analysis of Incorrect Options: * **Femoral artery (A):** This is the primary arterial content of the canal. It enters superiorly and traverses the entire length of the canal. * **Nerve to Vastus medialis (C):** This is a branch of the posterior division of the femoral nerve. it enters the canal and terminates by supplying the vastus medialis muscle. * **Saphenous nerve (D):** This is the longest cutaneous branch of the femoral nerve. It accompanies the femoral artery within the canal but exits by piercing the roof (vastoadductor fascia) to become superficial. ### High-Yield NEET-PG Pearls: * **Boundaries:** Anterolateral (Vastus medialis), Posterior (Adductor longus and magnus), and Medial/Roof (Sartorius). * **Contents mnemonic:** **"S-A-V-E"** — **S**aphenous nerve, **A**rtery (Femoral), **V**ein (Femoral), and **E**xtra nerve (Nerve to vastus medialis). * **Clinical Significance:** The adductor canal is the site for an **Adductor Canal Block**, commonly used for regional anesthesia in knee surgeries (e.g., TKR) because it provides sensory blockade (via the saphenous nerve) while sparing the motor power of the quadriceps.

Q: The Iliofemoral Ligament arises from which of the following structures?

Anterior Inferior Iliac Spine. **Explanation:** The **Iliofemoral ligament** (also known as the **Ligament of Bigelow**) is the strongest ligament in the human body. It is located on the anterior aspect of the hip joint capsule and plays a critical role in maintaining erect posture by preventing hyperextension of the hip. **Why the correct answer is right:** The ligament has a characteristic inverted **'Y' shape**. Its apex (proximal attachment) arises from the **Anterior Inferior Iliac Spine (AIIS)** and the adjoining part of the acetabular rim. Distally, it divides into two bands that attach to the upper and lower parts of the **intertrochanteric line** of the femur. **Analysis of Incorrect Options:** * **A. Ischial tuberosity:** This is the origin for the hamstring muscles and the sacrotuberous ligament. The ligament associated with the ischium is the *Ischiofemoral ligament*, which reinforces the posterior aspect of the hip. * **B. Anterior Superior Iliac Spine (ASIS):** This is the origin for the Sartorius muscle and the lateral end of the Inguinal ligament. * **C. Iliopubic Rami:** The *Pubofemoral ligament* arises from the iliopubic eminence and the obturator crest, reinforcing the inferior and anterior aspects of the joint. **High-Yield Clinical Pearls for NEET-PG:** * **Function:** It is most taut during **extension** and helps maintain balance without muscular effort while standing. * **Strength:** It can withstand a tensile force of up to 350 kg. * **Surgical Significance:** During a posterior dislocation of the hip, this ligament usually remains intact, acting as a fulcrum during reduction maneuvers (e.g., Bigelow's maneuver). * **Mnemonic:** Remember **"AIIS to Intertrochanteric line"** for the Iliofemoral ligament.

Q: The spring ligament complex consists of all of the following except?

Plantar calcaneocuboid ligament. The **Spring Ligament Complex** (also known as the Plantar Calcaneonavicular Ligament complex) is a vital structure that supports the head of the talus and maintains the medial longitudinal arch of the foot. ### **Why Option A is Correct** The **Plantar calcaneocuboid ligament** (also known as the **Short Plantar Ligament**) is located on the lateral side of the foot, connecting the calcaneus to the cuboid. It is anatomically distinct from the spring ligament complex, which specifically connects the calcaneus to the navicular bone. ### **Analysis of Other Options** The spring ligament is not a single band but a complex consisting of three distinct components: * **Option B (Plantar calcaneonavicular ligament):** Also called the *inferior* component, it is the widest and strongest part of the complex. * **Option C (Medial calcaneonavicular ligament):** Also called the *superomedial* component, it is the most clinically significant portion as it supports the talar head medially. * **Option D (Lateral calcaneonavicular ligament):** Also called the *medioplantar* component, it lies between the superomedial and inferior bands. ### **Clinical Pearls for NEET-PG** * **The "Spring" Function:** Despite its name, the ligament contains very little elastic tissue; its primary role is to act as a "hammock" for the head of the talus. * **Flat Foot (Pes Planus):** Chronic attenuation or rupture of the spring ligament (often associated with **Tibialis Posterior tendon** dysfunction) leads to the collapse of the medial longitudinal arch. * **Attachments:** It spans the gap between the **Sustentaculum tali** of the calcaneus and the **Navicular bone**. * **High-Yield Association:** The superior surface of the ligament is lined with fibrocartilage and forms part of the articular cavity for the talocalcaneonavicular joint.

Q: Which of the following tendons has attachments on the sustentaculum tali?

Tibialis Posterior. ### Explanation The **sustentaculum tali** is a shelf-like bony projection on the medial aspect of the calcaneus. It serves as a critical landmark for the passage of tendons from the posterior compartment of the leg into the sole of the foot. **Why Tibialis Posterior is Correct:** The **Tibialis Posterior** is the "master of the foot's arch." While its primary insertion is on the navicular tuberosity, it has extensive slip-like attachments to almost all tarsal bones (except the talus), including the **sustentaculum tali**, and the bases of the 2nd, 3rd, and 4th metatarsals. These multiple attachments allow it to provide significant dynamic support to the medial longitudinal arch. **Analysis of Incorrect Options:** * **Flexor Digitorum Longus (FDL):** This tendon passes **over** the medial surface of the sustentaculum tali but does not attach to it. * **Flexor Hallucis Longus (FHL):** This tendon passes through a distinct **groove on the inferior surface** of the sustentaculum tali. It uses the projection as a pulley but has no bony attachment there. * **Tibialis Anterior:** This muscle belongs to the anterior compartment of the leg. It inserts into the medial cuneiform and the base of the 1st metatarsal, far anterior to the calcaneus. **High-Yield NEET-PG Pearls:** 1. **Structures passing deep to Flexor Retinaculum (Medial to Lateral):** **T**ibialis posterior, flexor **D**igitorum longus, posterior tibial **A**rtery, tibial **N**erve, flexor **H**allucis longus (Mnemonic: **T**om **D**ick **A**nd **N**ervous **H**arry). 2. **Spring Ligament:** The sustentaculum tali provides the posterior attachment for the plantar calcaneonavicular (spring) ligament, which supports the head of the talus. 3. **FHL Landmark:** The FHL is the deepest tendon and is often identified in imaging by its position directly beneath the sustentaculum tali.

Question 1

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 2

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 3

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 4

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 5

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 6

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 7

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

Question 8

The Iliofemoral Ligament arises from which of the following structures?

Accepted Answer

Anterior Inferior Iliac Spine

Answer

Ischial tuberosity

Answer

Anterior Superior Iliac Spine

Answer

Iliopubic Rami

Question 9

The spring ligament complex consists of all of the following except?

Accepted Answer

Plantar calcaneocuboid ligament

Answer

Plantar calcaneonavicular ligament

Answer

Medial calcaneonavicular ligament

Answer

Lateral calcaneonavicular ligament

Question 10

Which of the following tendons has attachments on the sustentaculum tali?

Accepted Answer

Tibialis Posterior

Answer

Tibialis Anterior

Answer

Flexor digitorum longus

Answer

Flexor hallucis longus

Lower Limb — MCQs

Lower Limb — MCQs

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