Leg and Foot — MCQs

10 questions

Tibialis posterior is inserted in all of the following bones distally, except for which of the following?

A policeman found a person lying unconscious in the lateral position on the road with superficial injury to the face, bruises on the right arm, and injury to the lateral aspect of the right knee. Given the mechanism of injury and positioning, which nerve is most probably injured?

A patient underwent a coronary artery bypass graft (CABG) using the great saphenous vein. Post-surgery, the patient experiences neuralgia on the medial aspect of the leg and foot. Which nerve is most likely injured?

Foot drop occurs due to the involvement of:

Which nerve is commonly damaged in fracture of neck of fibula?

What is the consequence of tibial nerve injury/palsy?

Foot eversion is caused by

Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.

The rephrased question is:What is the most common complication of a fractured talus?

Q10

Injury at which of the following marked sites on the leg causes failure of dorsiflexion?

Leg and Foot Indian Medical PG Practice Questions and MCQs

Question 1: Tibialis posterior is inserted in all of the following bones distally, except for which of the following?

A. Metatarsal 2
B. Talus (Correct Answer)
C. Navicular bone
D. Intermediate cuneiform

Explanation: ***Talus*** - The **tibialis posterior muscle inserts** primarily into the **navicular, cuneiforms (medial, intermediate, lateral), cuboid**, and the bases of the **2nd, 3rd, and 4th metatarsals**. - The **talus** is a crucial bone in the ankle joint but does not serve as an insertion point for the tibialis posterior. *Metatarsal 2* - The tibialis posterior has **tendinous slips** that insert onto the **bases of the 2nd, 3rd, and 4th metatarsals**, contributing to the support of the medial longitudinal arch. - This insertion point helps in the muscle's function of **plantarflexion and inversion** of the foot. *Navicular bone* - The **navicular tuberosity** is a major insertion site for the tibialis posterior tendon, making it a key anatomical landmark for palpation. - Its strong attachment here is crucial for the muscle's role in **inverting the foot** and supporting the **medial longitudinal arch. *Intermediate cuneiform* - One of the **three cuneiform bones**, the intermediate cuneiform, receives an insertion from the tibialis posterior tendon. - This attachment point, along with others, allows the tibialis posterior to **control foot mechanics** and provide stability.

Question 2: A policeman found a person lying unconscious in the lateral position on the road with superficial injury to the face, bruises on the right arm, and injury to the lateral aspect of the right knee. Given the mechanism of injury and positioning, which nerve is most probably injured?

A. Femoral nerve
B. Common peroneal nerve (Correct Answer)
C. Radial nerve
D. Trigeminal nerve

Explanation: **Correct: Common peroneal nerve** - The **lateral aspect of the right knee** is particularly vulnerable to direct trauma to the **common peroneal nerve** due to its superficial course around the neck of the fibula. - The unconscious state and lateral position suggest a prolonged compression or direct impact mechanism, making this nerve highly susceptible to injury. - The common peroneal nerve is the **most commonly injured nerve in the lower limb** due to its superficial location. *Incorrect: Femoral nerve* - The **femoral nerve** runs deep within the groin region and anterior thigh, making direct injury at the knee unlikely from an isolated lateral knee trauma. - Injuries to the femoral nerve typically result from pelvic fractures, abdominal surgery, or deep penetrating wounds to the groin. *Incorrect: Radial nerve* - The **radial nerve** is located in the upper limb and primarily affects the extensor muscles of the arm, forearm, and hand. - While bruises on the right arm are noted, an injury to the radial nerve would not explain the specific trauma to the lateral aspect of the knee. *Incorrect: Trigeminal nerve* - The **trigeminal nerve** is a cranial nerve responsible for sensation in the face and motor functions such as biting and chewing. - Superficial injury to the face might affect sensory branches, but it is entirely unrelated to an injury to the lateral aspect of the knee.

Question 3: A patient underwent a coronary artery bypass graft (CABG) using the great saphenous vein. Post-surgery, the patient experiences neuralgia on the medial aspect of the leg and foot. Which nerve is most likely injured?

A. Common peroneal nerve
B. Sural nerve
C. Tibial nerve
D. Saphenous nerve (Correct Answer)
E. Superficial peroneal nerve

Explanation: ***Saphenous nerve*** - The **saphenous nerve** is a cutaneous branch of the femoral nerve that runs closely with the **great saphenous vein** along the medial aspect of the leg and foot. - Due to its proximity to the vein, it is highly susceptible to **injury** during the harvesting of the great saphenous vein for CABG, leading to **neuralgia** in its sensory distribution. *Common peroneal nerve* - The **common peroneal nerve** innervates the lateral and anterior compartments of the leg, affecting dorsiflexion and eversion of the foot. - Damage to this nerve typically results in **foot drop** and sensory loss over the dorsum of the foot, which is inconsistent with the patient's symptoms. *Tibial nerve* - The **tibial nerve** supplies the posterior compartment of the leg and the plantar aspect of the foot. - Injury would cause loss of plantarflexion and sensation on the sole of the foot, which is not described. *Sural nerve* - The **sural nerve** provides sensation to the posterolateral aspect of the leg and the lateral side of the foot and ankle. - While it runs near superficial veins, its sensory distribution does not match the described **medial leg and foot neuralgia**. *Superficial peroneal nerve* - The **superficial peroneal nerve** (superficial fibular nerve) provides sensation to the dorsum of the foot and anterolateral leg. - Injury would cause sensory loss over the dorsal foot, not the medial aspect of the leg and foot.

Question 4: Foot drop occurs due to the involvement of:

A. Obturator nerve
B. Sciatic nerve
C. Direct injury to the dorsiflexors
D. Common peroneal nerve palsy (Correct Answer)

Explanation: ***Common peroneal nerve palsy*** - The **common peroneal nerve** (also known as the common fibular nerve) innervates the muscles responsible for **dorsiflexion** and eversion of the foot (tibialis anterior, extensor hallucis longus, extensor digitorum longus, peroneus longus and brevis). - Damage to this nerve leads to weakness or paralysis of these muscles, resulting in **foot drop**, which is the most common neurological cause. - The nerve is vulnerable at the **neck of the fibula** where it is superficial and can be compressed or injured. *Sciatic nerve* - The **sciatic nerve** divides into the tibial and common peroneal nerves. - Proximal sciatic nerve injury can cause foot drop, but it would also cause additional deficits including hamstring weakness, loss of ankle plantarflexion, and sensory loss over a wider distribution. - Isolated foot drop typically indicates **common peroneal nerve** injury, not sciatic nerve injury. *Direct injury to the dorsiflexors* - Direct trauma to the **dorsiflexor muscles** (tibialis anterior, extensor hallucis longus, extensor digitorum longus) can mechanically impair dorsiflexion. - However, the term "foot drop" typically refers to **neurological causes** rather than direct muscle injury, making common peroneal nerve palsy the more specific answer. *Obturator nerve* - The **obturator nerve** innervates the **adductor muscles of the thigh** (adductor longus, adductor brevis, adductor magnus, gracilis). - It does not innervate any muscles responsible for dorsiflexion of the foot and therefore **cannot cause foot drop**.

Question 5: Which nerve is commonly damaged in fracture of neck of fibula?

A. Tibial
B. Common peroneal (Correct Answer)
C. Superficial peroneal
D. Deep peroneal

Explanation: ***Common peroneal*** - The **common peroneal nerve** (also known as the **common fibular nerve**) wraps superficially around the **neck of the fibula**, making it highly vulnerable to injury in fractures of this region. - Damage to this nerve typically results in **foot drop** and sensory loss over the dorsum of the foot and lateral leg, due to impaired dorsiflexion and eversion. *Tibial* - The **tibial nerve** lies in the posterior compartment of the leg and is generally well-protected, making it less susceptible to injury from a fibular neck fracture. - Injury to the tibial nerve would primarily affect plantarflexion of the foot and sensation to the sole. *Superficial peroneal* - The **superficial peroneal nerve** is a branch of the common peroneal nerve that descends along the lateral compartment of the leg. - While it originates from the common peroneal, a direct fracture of the fibular neck is more likely to injure the main common peroneal trunk rather than just this specific branch, leading to a broader deficit. *Deep peroneal* - The **deep peroneal nerve** is another branch of the common peroneal nerve that runs through the anterior compartment of the leg. - Similar to the superficial peroneal nerve, a fracture at the fibular neck is more likely to affect the main **common peroneal nerve** directly.

Question 6: What is the consequence of tibial nerve injury/palsy?

A. Loss of plantar flexion (Correct Answer)
B. Dorsiflexion of foot at ankle joint
C. Loss of sensation of dorsum of foot
D. Paralysis of muscles of anterior compartment of leg

Explanation: **Loss of plantar flexion** - The **tibial nerve** innervates the muscles of the **posterior compartment of the leg**, which are primarily responsible for **plantar flexion** of the foot. - Injury to this nerve directly impairs the function of muscles like the gastrocnemius, soleus, and tibialis posterior, leading to a significant loss of the ability to point the foot downwards. *Dorsiflexion of foot at ankle joint* - **Dorsiflexion** is primarily mediated by muscles in the **anterior compartment of the leg**, such as the tibialis anterior, which are innervated by the **deep fibular nerve**. - Tibial nerve injury would not directly affect these muscles or their function; rather, it leads to issues with the opposing action. *Loss of sensation of dorsum of foot* - Sensation to the **dorsum of the foot** is primarily supplied by the **superficial fibular nerve** (for most of the dorsum) and the **deep fibular nerve** (for the first web space). - While the tibial nerve provides sensation to the sole of the foot, it does not typically innervate the dorsum. *Paralysis of muscles of anterior compartment of leg* - The muscles of the **anterior compartment of the leg** (e.g., tibialis anterior, extensor digitorum longus, extensor hallucis longus) are innervated by the **deep fibular nerve**. - A tibial nerve injury would paralyze muscles in the posterior compartment, not the anterior compartment.

Question 7: Foot eversion is caused by

A. Tibialis anterior
B. Tibialis posterior
C. Peroneus longus (Correct Answer)
D. Extensor digitorum

Explanation: ***Peroneus longus*** - The **peroneus longus** muscle (fibularis longus) is a primary evertor of the foot. - It originates from the head and upper lateral surface of the fibula, inserts into the medial cuneiform and first metatarsal, and its contraction pulls the foot outwards and downwards. *Tibialis anterior* - The **tibialis anterior** is the primary dorsiflexor and invertor of the foot. - It pulls the foot upwards and inwards, which is the opposite action of eversion. *Tibialis posterior* - The **tibialis posterior** is a strong invertor and plantar flexor of the foot. - It contributes to maintaining the arch of the foot and does not cause eversion. *Extensor digitorum* - The **extensor digitorum longus** primarily extends the toes and assists in dorsiflexion of the ankle. - While it may have a slight eversion component, it is not the primary muscle responsible for foot eversion.

Question 8: Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.

A. Statements 1 & 2 are correct, 2 is not explaining 1 (Correct Answer)
B. Statements 1 and 2 are correct and 2 is the correct explanation for 1
C. Statements 1 and 2 are incorrect
D. Statement 1 is incorrect

Explanation: ***Correct: Statements 1 & 2 are correct, 2 is not explaining 1*** **Analysis of Statement 1:** - A 59-year-old patient with **flaccid bullae** and **suprabasal acantholytic split** on histopathology is the classic presentation of **Pemphigus vulgaris** - The flaccid (easily ruptured) nature of bullae distinguishes it from tense bullae seen in bullous pemphigoid - The suprabasal location of the split (just above the basal layer) with acantholysis (loss of cell-to-cell adhesion) is pathognomonic - **Statement 1 is CORRECT** ✓ **Analysis of Statement 2:** - The **"row of tombstones" or "tombstone appearance"** is indeed a diagnostic histopathological feature of Pemphigus vulgaris - This appearance results from basal keratinocytes remaining attached to the basement membrane while suprabasal cells separate due to acantholysis - The intact basal cells standing upright resemble a row of tombstones - **Statement 2 is CORRECT** ✓ **Does Statement 2 explain Statement 1?** - Statement 2 describes a **histopathological appearance** (tombstone pattern) that is a **consequence** of the suprabasal split - However, it does NOT explain the **underlying cause** of the flaccid bullae or the suprabasal split - The true explanation involves **IgG autoantibodies against desmoglein 3 (and desmoglein 1)**, which attack intercellular adhesion structures (desmosomes), causing **acantholysis** - Therefore, **Statement 2 does NOT explain Statement 1** ✗ *Incorrect: Statement 2 is the correct explanation for Statement 1* - While both statements describe features of Pemphigus vulgaris, the tombstone appearance is a descriptive finding, not an explanatory mechanism *Incorrect: Statements 1 and 2 are incorrect* - Both statements are medically accurate descriptions of Pemphigus vulgaris features *Incorrect: Statement 1 is incorrect* - Statement 1 correctly describes the cardinal clinical and histopathological features of Pemphigus vulgaris

Question 9: The rephrased question is:What is the most common complication of a fractured talus?

A. Avascular necrosis (AVN) (Correct Answer)
B. Osteoarthritis of the subtalar joint
C. Nonunion of the talus
D. Osteoarthritis of the ankle joint

Explanation: ***Avascular necrosis (AVN)*** - The talus has a **precarious blood supply**, with arterial branches entering at multiple points but often centrally, making it vulnerable to **ischemia** after fracture. - Fractures, especially neck fractures, can disrupt these delicate vessels, leading to **osteonecrosis** and collapse of the bone. *Nonunion of the talus* - While possible, talar nonunion is **less common** than AVN due to the talus's dense cortical bone and limited muscle attachments. - Nonunion is more frequently seen with fractures of other bones, such as the **scaphoid**. *Osteoarthritis of the subtalar joint* - **Subtalar osteoarthritis** can occur post-talar fracture, often as a **secondary complication** of disrupted articular surfaces or AVN. - However, the **initial and most common direct complication** stemming from the blood supply disruption is AVN. *Osteoarthritis of the ankle joint* - **Ankle osteoarthritis** can also develop after certain talar fractures, particularly those involving the talar dome or leading to incongruity of the ankle joint. - Similar to subtalar arthritis, it is often a **later or secondary sequela**, rather than the immediate and most frequent direct complication like AVN.

Question 10: Injury at which of the following marked sites on the leg causes failure of dorsiflexion?

A. Anterior aspect of the thigh (site 1)
B. Medial aspect of the leg (site 4)
C. Lateral aspect of the leg (site 3) (Correct Answer)
D. Posterior aspect of the thigh (site 2)

Explanation: ***Lateral aspect of the leg (site 3)*** - Site 3 points to the **fibula head** and the adjacent region on the lateral aspect of the leg. This is the anatomical location where the **common fibular nerve (peroneal nerve)** wraps around. - The common fibular nerve innervates the muscles responsible for **dorsiflexion** and eversion of the foot. Damage to this nerve, often due to trauma at the fibular neck, leads to **foot drop** and an inability to dorsiflex the foot. *Anterior aspect of the thigh (site 1)* - Site 1 points to the distal femur, which is part of the thigh. Nerves in the anterior thigh (e.g., **femoral nerve**) primarily control hip flexion and knee extension. - Damage here would affect movements of the hip and knee, not directly causing failure of dorsiflexion of the foot. *Medial aspect of the leg (site 4)* - Site 4 points to the medial tibia. This area is associated with the **tibial nerve** and saphenous nerve, which primarily innervate muscles for plantarflexion and inversion of the foot, or provide sensory innervation. - Injury to the tibial nerve would result in an inability to plantarflex and invert the foot, not dorsiflexion. *Posterior aspect of the thigh (site 2)* - Site 2 points to the posterior aspect of the thigh, which is the region for the hamstrings. The **sciatic nerve** and its branches (tibial and common fibular) pass through this region. - While the common fibular nerve originates from the sciatic nerve in the posterior thigh, an injury at this level would likely cause more widespread motor and sensory deficits than isolated dorsiflexion failure, and site 3 is a more common and specific site for common fibular nerve injury isolated to foot drop.

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