Lower Limb — MCQs

Lower Limb Indian Medical PG Practice Questions and MCQs

Question 491: Primary afferent nerve of the cremasteric reflex is

A. Genitofemoral nerve (Correct Answer)
B. Pudendal nerve
C. Ilioinguinal nerve
D. Iliohypogastric nerve

Explanation: ***Genitofemoral nerve*** - The **genitofemoral nerve** (L1-L2) innervates the cremaster muscle and carries both afferent (sensory) and efferent (motor) fibers for the cremasteric reflex. - The **afferent limb** of the reflex is stimulated when the skin of the upper inner thigh is stroked, and this sensory input travels via the **femoral branch of the genitofemoral nerve** to the spinal cord (L1-L2 segments). - The **efferent limb** travels via the **genital branch of the genitofemoral nerve** to stimulate contraction of the cremaster muscle, elevating the testis. *Pudendal nerve* - The **pudendal nerve** primarily innervates the perineum (external genitalia, anus, and sphincter muscles). - It is involved in micturition, defecation, and sensation from the perineum but not directly in the cremasteric reflex. *Ilioinguinal nerve* - The **ilioinguinal nerve** provides sensation to the skin of the upper medial thigh, root of the penis/mons pubis, and parts of the scrotum/labia majora, and innervates some abdominal muscles. - While it runs in the inguinal region and provides overlapping sensory distribution, it does not form the primary afferent limb of the cremasteric reflex. *Iliohypogastric nerve* - The **iliohypogastric nerve** primarily innervates the skin over the gluteal region and the suprapubic area, as well as providing motor innervation to the internal oblique and transversus abdominis muscles. - It is not involved in the cremasteric reflex pathway.

Question 492: Foot drop is caused due to injury to which nerve?

A. Obturator Nerve
B. Tibial Nerve
C. Common Peroneal Nerve (Correct Answer)
D. Femoral Nerve

Explanation: Common peroneal nerve - Injury to the common peroneal nerve (also known as the common fibular nerve) leads to weakness or paralysis of the muscles responsible for dorsiflexion and eversion of the foot. - This results in a condition called foot drop, where the foot cannot be lifted at the ankle, causing a characteristic high-stepping or steppage gait. Obturator Nerve - The obturator nerve primarily innervates the adductor muscles of the thigh, which are responsible for pulling the legs together. - Injury to this nerve would cause difficulty with leg adduction and sensation over the medial thigh, not foot drop. Tibial Nerve - The tibial nerve innervates the muscles of the posterior compartment of the leg, responsible for plantarflexion and inversion of the foot. - Damage to the tibial nerve would result in an inability to stand on tiptoes or reduced sensation in the sole of the foot, not foot drop. Femoral Nerve - The femoral nerve innervates the quadriceps femoris muscle, essential for knee extension, and also provides sensation to the anterior thigh and medial leg. - Injury to this nerve would primarily lead to weakness in knee extension and difficulty climbing stairs, not foot drop.

Question 493: Housemaid's knee is inflammation of:

A. Anserine bursa
B. Infrapatellar bursa
C. Prepatellar bursa (Correct Answer)
D. Suprapatellar bursa

Explanation: ***Prepatellar bursa*** - **Housemaid's knee** refers to **prepatellar bursitis**, an inflammation of the bursa located anterior to the patella. - This condition is often caused by **prolonged kneeling**, leading to frictional irritation and inflammation of the prepatellar bursa. *Anserine bursa* - Inflammation of the anserine bursa is known as **pes anserine bursitis**, typically causing pain on the medial aspect of the knee below the joint line. - It is not commonly referred to as "housemaid's knee" and is associated with conditions like **osteoarthritis** or overuse in runners. *Infrapatellar bursa* - Inflammation of the infrapatellar bursa is known as **clergyman's knee**, causing pain below the patella, either superficial or deep. - It is typically caused by repetitive kneeling or direct trauma to the area just below the kneecap. - Note: **Jumper's knee** refers to patellar tendinitis, not bursitis. *Suprapatellar bursa* - The suprapatellar bursa is located superior to the patella, communicating with the knee joint. - Inflammation of this bursa is less common in isolation and usually associated with **effusion within the knee joint itself**.

Question 494: Which of the following muscles do NOT work for inversion of foot?

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

Explanation: ***Peroneus longus*** - The **peroneus longus** (also known as the fibularis longus) is a primary **evertor** of the foot and also contributes to plantarflexion. - Its insertion on the **medial cuneiform** and base of the first metatarsal provides a pull that turns the sole of the foot outwards, opposing inversion. *Tibialis posterior* - The **tibialis posterior** is a primary and powerful **inverter** of the foot, inserting on multiple tarsal bones and metatarsals. - It also aids in **plantarflexion** and helps maintain the medial longitudinal arch of the foot. *Tibialis anterior* - The **tibialis anterior** is a strong **inverter** of the foot, inserting on the medial cuneiform and base of the first metatarsal. - It works synergistically with the tibialis posterior for inversion and is also a primary **dorsiflexor** of the ankle. *Extensor hallucis longus* - The **extensor hallucis longus** contributes to **inversion** of the foot, though its primary action is to **extend the great toe**. - Its partial line of pull contributes to turning the sole of the foot inward during its action.

Question 495: Which ligament prevents hyperextension of the knee joint?

A. Lateral collateral
B. Anterior cruciate (Correct Answer)
C. Posterior cruciate
D. Medial collateral

Explanation: ***Anterior cruciate*** - The **anterior cruciate ligament (ACL)** is the **primary restraint against hyperextension** of the knee joint - It prevents **anterior translation of the tibia** relative to the femur and tightens during terminal extension to limit hyperextension - The ACL is crucial for maintaining knee stability during activities that involve sudden stops or changes in direction *Posterior cruciate* - The **posterior cruciate ligament (PCL)** prevents **posterior translation of the tibia** relative to the femur - It is the primary restraint during **knee flexion** and prevents excessive flexion, NOT hyperextension - The PCL is stronger than the ACL and is less commonly injured *Lateral collateral* - The **lateral collateral ligament (LCL)** is located on the outer side of the knee and primarily resists **varus stress** (forces that would create a bow-legged deformity) - It does not play a significant role in preventing hyperextension *Medial collateral* - The **medial collateral ligament (MCL)** is located on the inner side of the knee and primarily resists **valgus stress** (forces that would create a knock-kneed deformity) - It does not play a significant role in preventing hyperextension

Question 496: Which spinal nerve roots contribute to the formation of the sciatic nerve?

A. L1-L3
B. L4-S3 (Correct Answer)
C. L2-L4
D. S1-S4

Explanation: ***L4-S3*** - The **sciatic nerve** is the largest nerve in the body, formed from the confluence of nerve roots from the **lumbar (L4, L5)** and **sacral (S1, S2, S3)** plexuses. - These nerve roots combine to form the sciatic nerve, which then travels down the posterior thigh. *L1-L3* - These nerve roots primarily contribute to the formation of the **femoral nerve** (L2-L4) and obturator nerve (L2-L4), which innervate the anterior and medial compartments of the thigh, respectively. - They do not directly contribute to the formation of the sciatic nerve. *L2-L4* - Nerve roots from **L2, L3, and L4** primarily form the **femoral nerve** and the **obturator nerve**. - While L4 is a component of the sciatic nerve, L2 and L3 are not. *S1-S4* - While **S1, S2, and S3** contribute to the sciatic nerve, the inclusion of S4 is incorrect for its primary formation. - The S4 nerve root has other significant roles, including contributions to the **pudendal nerve**.

Question 497: What are the actions of the sartorius muscle?

A. Hip flexion and knee extension
B. Hip extension and knee flexion
C. Hip abduction and knee extension
D. Hip flexion and knee flexion (Correct Answer)

Explanation: Hip flexion and knee flexion - The sartorius muscle is the longest muscle in the body, originating from the anterior superior iliac spine (ASIS) and inserting into the medial tibial condyle. - Its diagonal path allows it to perform hip flexion (pulling the thigh upwards) and knee flexion (bending the knee). - These are the two primary actions of the sartorius muscle. Hip flexion and knee extension - While the sartorius performs hip flexion, it does not perform knee extension. - Knee extension is primarily carried out by the quadriceps femoris muscle. Hip extension and knee flexion - The sartorius does not contribute to hip extension; this action is primarily performed by the gluteus maximus and hamstrings. - While it does perform knee flexion, its role in hip movement is flexion, not extension. Hip abduction and knee extension - Although the sartorius does contribute to hip abduction (as a secondary action), it does not perform knee extension. - The combination stated in this option is incorrect because sartorius flexes the knee rather than extending it.

Question 498: A 60-year-old female presents with weakness in dorsiflexion of the foot and sensory loss in the web space between the first and second toes. Which nerve is likely to be involved?

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

Explanation: ***Deep peroneal nerve*** - This nerve innervates **anterior compartment muscles** responsible for **dorsiflexion** of the foot. - It also provides sensory innervation to the **web space between the first and second toes**, matching the patient's symptoms. *Sural nerve* - The sural nerve provides **sensory innervation** to the lateral aspect of the foot and ankle and has no motor function related to foot dorsiflexion. - Damage to this nerve typically presents as numbness or paresthesia along the **lateral calf and foot**. *Superficial peroneal nerve* - This nerve primarily innervates the **lateral compartment muscles**, responsible for **eversion of the foot**. - Its sensory distribution includes the dorsum of the foot, but **excludes the first web space**. *Tibial nerve* - The tibial nerve innervates the **posterior compartment muscles** of the leg, controlling **plantarflexion** and toe flexion. - Sensory loss associated with tibial nerve injury typically affects the **sole of the foot**.

Question 499: During a physical examination, a 60-year-old man is found to have a pulsatile mass in his left popliteal fossa. Which artery is most likely involved?

A. Popliteal artery (Correct Answer)
B. Femoral artery
C. Tibial artery
D. Peroneal artery

Explanation: Popliteal artery - The **popliteal artery** is located in the **popliteal fossa**, the anatomical space behind the knee [1], [2]. A pulsatile mass in this location is a classic presentation of a **popliteal artery aneurysm** [2]. - **Popliteal artery aneurysms** are the most common peripheral aneurysms and are frequently associated with **abdominal aortic aneurysms** [1]. *Femoral artery* - The **femoral artery** is located in the **groin region** and passes down the thigh, not in the popliteal fossa [1]. - A pulsatile mass involving the femoral artery would be found in the **thigh** or **groin**, not behind the knee. *Tibial artery* - The **tibial arteries** (anterior and posterior) are located in the **lower leg** below the knee, supplying the foot [3]. - While they are palpable, a pulsatile mass in the popliteal fossa would not typically be attributed to these vessels, as they are distal to this region. *Peroneal artery* - The **peroneal artery** is also located in the **lower leg**, deep within the posterior compartment [1]. - Similar to the tibial arteries, an aneurysm of the peroneal artery would present in the lower leg and not in the popliteal fossa.

Question 500: A patient presents with difficulty extending the knee following a traumatic injury. Which nerve is most likely to be injured?

A. Sciatic nerve
B. Tibial nerve
C. Femoral nerve (Correct Answer)
D. Obturator nerve

Explanation: ***Femoral nerve*** - The **femoral nerve** innervates the **quadriceps femoris muscles**, which are the primary extensors of the knee. - Injury to this nerve would directly impair the ability to **extend the knee**, as described in the patient's presentation. *Sciatic nerve* - The **sciatic nerve** primarily innervates the muscles of the posterior thigh (hamstrings) for **knee flexion** and muscles of the leg and foot. - Injury would result in difficulty with hip extension and knee flexion, as well as foot drop, not knee extension deficits. *Tibial nerve* - The **tibial nerve** is a branch of the sciatic nerve, innervating muscles in the posterior compartment of the leg and plantar foot muscles. - Its primary actions are **plantarflexion of the foot and flexion of the toes**, with no direct role in knee extension. *Obturator nerve* - The **obturator nerve** innervates the **adductor muscles of the thigh**, which are responsible for adducting the hip. - Injury to this nerve would primarily affect hip adduction and sensation in the medial thigh, not knee extension.

Practice by Chapter

Gluteal Region and Hip

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Thigh and Popliteal Fossa

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Leg and Foot

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Joints of Lower Limb

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Nerves of Lower Limb

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Arterial Supply and Venous Drainage

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Lymphatic Drainage

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Muscles and Their Actions

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Gait Analysis and Biomechanics

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Applied Anatomy and Clinical Correlations

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Lower Limb — MCQs

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