Lower Limb Practice Questions

Q: Locking of the knee joint occurs with all except?

Popliteus. **Explanation:** The mechanism of the knee joint involves two distinct processes: **Locking** and **Unlocking**. **1. Why Popliteus is the correct answer:** Locking is the final stage of knee extension where the femur undergoes **medial rotation** (on a fixed tibia) to tighten the ligaments, making the joint stable and rigid. This process is driven by the **Quadriceps femoris** group. In contrast, **Popliteus** is the "Key to the knee." Its primary function is **Unlocking** the knee by initiating **lateral rotation** of the femur on the tibia (or medial rotation of the tibia if the foot is free) at the start of flexion. Therefore, it is not involved in locking; it is the essential muscle for reversing it. **2. Why the other options are incorrect:** * **Vastus medialis (specifically the VM Obliquus):** This is the most crucial muscle for the final 10–15 degrees of extension and the terminal locking of the knee. * **Vastus intermedius & Rectus femoris:** As components of the Quadriceps femoris, these muscles are powerful extensors of the knee. Since locking is a phenomenon of terminal extension, all components of the quadriceps contribute to the force required to achieve a locked position. **Clinical Pearls for NEET-PG:** * **Locking:** Occurs in full extension; involves **Medial rotation** of the femur. * **Unlocking:** Occurs at the start of flexion; involves **Lateral rotation** of the femur, performed by the **Popliteus**. * **Popliteus Origin/Insertion:** It is unique because it is an **intracapsular but extrasynovial** muscle, originating from the lateral condyle of the femur. * **Nerve Supply:** Tibial Nerve (L4, L5, S1).

Q: Which of the following ligaments prevents hyperextension of the hip?

Iliofemoral ligament. **Explanation:** The hip joint is stabilized by three main extracapsular ligaments. The **Iliofemoral ligament** (also known as the **Y-shaped ligament of Bigelow**) is the strongest ligament in the body. It is located anteriorly and becomes taut during extension. Its primary function is to **prevent hyperextension** of the hip joint during standing, maintaining posture without requiring constant muscular activity. **Analysis of Options:** * **A. Iliofemoral ligament (Correct):** Attached to the anterior inferior iliac spine and the intertrochanteric line. It resists hyperextension and is the most significant stabilizer of the joint. * **B. Pubofemoral ligament:** Located anteroinferiorly, it primarily limits **excessive abduction** and extension. * **C. Ischiofemoral ligament:** Located posteriorly, it is the weakest of the three. It limits **internal rotation** and extension. * **D. Ligamentum teres:** An intracapsular ligament that carries the artery to the head of the femur (branch of the obturator artery). It plays a minimal role in joint stability but is crucial for vascularity in early childhood. **High-Yield NEET-PG Pearls:** * **Screw-home mechanism of the hip:** During extension, all three ligaments (iliofemoral, pubofemoral, and ischiofemoral) twist and tighten, pulling the femoral head into the acetabulum to lock the joint. * **Strength:** The Iliofemoral ligament can withstand a tensile force of up to 350 kg. * **Clinical Correlation:** In cases of hip dislocation, the iliofemoral ligament often remains intact and is used as a fulcrum for reduction maneuvers.

Q: A 75-year-old man is transported to the emergency department with severe pain of his right hip and thigh. A radiographic examination reveals avascular necrosis of the femoral head. Which of the following conditions most likely occurred to produce avascular necrosis in this patient?

Intracapsular femoral neck fracture. **Explanation:** The blood supply to the head of the femur is primarily derived from the **medial circumflex femoral artery (MCFA)** via its retinacular branches. These vessels run along the femoral neck and pierce the joint capsule to reach the head. **1. Why Intracapsular Femoral Neck Fracture is Correct:** The femoral head is an **intracapsular** structure. A fracture of the femoral neck (intracapsular) frequently tears the retinacular vessels. Because the femoral head has a precarious blood supply with limited collateral circulation in adults, this disruption leads to **Avascular Necrosis (AVN)** [1]. **2. Analysis of Incorrect Options:** * **Thrombosis of the obturator artery:** The obturator artery gives off the *artery of the ligamentum teres*. While crucial in children, this artery is often obliterated or insufficient to maintain viability of the femoral head in elderly adults. * **Intertrochanteric fracture:** These are **extracapsular** fractures. The blood supply to the head (retinacular vessels) enters proximal to the trochanteric line, meaning it usually remains intact in these injuries. * **Comminuted extracapsular fracture:** Similar to intertrochanteric fractures, being extracapsular means the main retinacular blood supply is distal to the fracture line and typically preserved. **NEET-PG High-Yield Pearls:** * **Primary Source:** Medial Circumflex Femoral Artery (MCFA) is the most important contributor to the femoral head. * **Cruciate Anastomosis:** Provides collateral circulation around the hip (formed by Medial/Lateral Circumflex Femoral, Inferior Gluteal, and First Perforating arteries). * **Garden Classification:** Used to grade femoral neck fractures; higher grades (III & IV) have a significantly higher risk of AVN. * **Clinical Sign:** A patient with a femoral neck fracture typically presents with a shortened and **externally rotated** limb [1].

Q: Which of the following muscles has an intracapsular origin?

Popliteus. The Popliteus muscle is unique in the lower limb due to its intracapsular but extrasynovial origin. It arises from the popliteal groove on the lateral condyle of the femur via a strong tendon. This tendon pierces the posterior part of the capsule of the knee joint and runs between the fibrous capsule and the synovial membrane to reach its insertion on the posterior surface of the tibia. Why the other options are incorrect: * Plantaris: Originates from the lower part of the lateral supracondylar line of the femur and the oblique popliteal ligament. Its origin is entirely extracapsular. * Gastrocnemius: The lateral head originates from the lateral surface of the lateral condyle, and the medial head from the popliteal surface of the femur above the medial condyle. Both origins are extracapsular. * Soleus: Originates from the posterior aspect of the head and upper shaft of the fibula and the soleal line of the tibia. It is located deep in the calf, far below the knee joint capsule. High-Yield Clinical Pearls for NEET-PG: * "Key to the Knee": The Popliteus is responsible for unlocking the knee joint by laterally rotating the femur on the fixed tibia (in closed chain) or medially rotating the tibia (in open chain) to initiate flexion. * Morphology: It is considered the "remnant of the second head of the internal obturator muscle" in some evolutionary contexts, but clinically, its tendon is a landmark that separates the lateral meniscus from the fibular collateral ligament. * Bursa: The popliteus bursa usually communicates with the synovial cavity of the knee joint.

Q: A 58-year-old female employee of a housecleaning business visits the outpatient clinic with a complaint of constant, burning pain in her knees. Clinical examinations reveal a "housemaid's knee" condition. Which of the following structures is most likely affected?

Prepatellar bursa. **Explanation:** The patient is presenting with **Housemaid’s Knee**, clinically known as **Prepatellar Bursitis**. **Why the Prepatellar Bursa is correct:** The prepatellar bursa is a synovial sac located subcutaneously between the skin and the anterior surface of the patella. Its primary function is to allow the skin to glide freely over the bone. Chronic friction or repetitive pressure—classically seen in occupations requiring frequent kneeling (like housecleaning or carpet laying)—leads to inflammation and fluid accumulation within this bursa. This results in localized swelling and "burning" pain over the front of the knee. **Analysis of Incorrect Options:** * **Infrapatellar bursa:** Inflammation here is known as **Clergyman’s Knee**. It is located deep or superficial to the patellar ligament. It occurs in those who kneel more upright (putting pressure on the tibial tuberosity), whereas housemaids lean forward, placing pressure directly on the patella. * **Posterior cruciate ligament (PCL):** This is an intra-articular ligament preventing posterior displacement of the tibia. Injury typically involves significant trauma (e.g., dashboard injury), not chronic kneeling. * **Patellar retinacula:** These are fibrous expansions of the vastus medialis and lateralis tendons. While they support the knee joint, they are not fluid-filled sacs prone to the "bursitis" described in the clinical vignette. **NEET-PG High-Yield Pearls:** * **Prepatellar Bursitis:** Housemaid’s Knee (Pressure on Patella). * **Infrapatellar Bursitis:** Clergyman’s Knee (Pressure on Tibial Tuberosity). * **Anserine Bursitis:** Pain on the medial aspect of the knee (Sartorius, Gracilis, Semitendinosus insertion); common in obese females with osteoarthritis. * **Baker’s Cyst:** Distension of the semimembranosus bursa in the popliteal fossa.

Q: The sustentaculum tali is present on which bone?

Calcaneus. The **sustentaculum tali** is a shelf-like bony projection located on the **medial surface** of the **calcaneus** (the heel bone). Its primary function is to support the head of the talus, which sits directly above it. ### Why Calcaneus is Correct: The sustentaculum tali acts as a structural pedestal. Its superior surface has an articular facet for the middle calcaneal facet of the talus. Crucially, its inferior surface features a groove for the **Flexor Hallucis Longus (FHL)** tendon, which uses the projection as a pulley. ### Why Other Options are Incorrect: * **Talus:** While the sustentaculum tali supports the talus, it is not part of it. The talus is the only tarsal bone with no muscular attachments. * **Navicular:** This bone lies anterior to the talus. It features a prominent **tuberosity** (insertion for Tibialis Posterior), not the sustentaculum. * **Cuneiform:** These are three small bones (medial, intermediate, lateral) in the midfoot that articulate with the metatarsals; they lack major shelf-like projections. ### High-Yield Clinical Pearls for NEET-PG: * **Spring Ligament:** The plantar calcaneonavicular (spring) ligament attaches to the sustentaculum tali. It supports the medial longitudinal arch; its failure leads to **flat foot (pes planus)**. * **Tarsal Tunnel:** The sustentaculum tali forms part of the floor of the tarsal tunnel. * **Mnemonic for Medial Malleolus structures (Front to Back):** **T**ibialis posterior, flexor **D**igitorum longus, posterior tibial **A**rtery, tibial **N**erve, flexor **H**allucis longus (**T**om, **D**ick **A**nd **N**ervous **H**arry). Remember: FHL is the deepest and passes under the sustentaculum tali.

Q: Which of the following forms the medial boundary of the lacunar ligament?

Lacunar ligament. The question focuses on the boundaries of the **femoral ring**, which is the upper opening of the femoral canal. Understanding these boundaries is high-yield for NEET-PG, particularly in the context of femoral hernias. ### **Explanation of the Correct Answer** The **lacunar ligament** (Gimbernat’s ligament) is a triangular extension of the medial end of the inguinal ligament. It attaches to the pectineal line of the pubis. In the context of the femoral ring: * **Medial Boundary:** Formed by the sharp, crescentic edge of the **lacunar ligament**. * **Lateral Boundary:** Formed by the **femoral vein** (separated by a septum). * **Anterior Boundary:** Formed by the **inguinal ligament** [1]. * **Posterior Boundary:** Formed by the **pectineal ligament** (Cooper’s ligament) and the **pectineus muscle** covering the superior ramus of the pubis [1]. ### **Analysis of Incorrect Options** * **B. Inguinal Ligament:** This forms the **anterior** boundary of the femoral ring. * **C. Femoral Vein:** This forms the **lateral** boundary of the femoral ring. * **D. Pectineus Muscle:** This (along with its fascia and the pectineal ligament) forms the **posterior** boundary. ### **Clinical Pearls for NEET-PG** 1. **Femoral Hernia:** Because the lacunar ligament is rigid and unyielding, it is the structure responsible for the **strangulation** of femoral hernias [1]. To release a strangulated hernia, the lacunar ligament is often incised. 2. **Corona Mortis:** An accessory obturator artery may run along the superior surface of the lacunar ligament. Surgeons must be cautious during hernia repair to avoid life-threatening hemorrhage. 3. **Femoral Canal Contents:** It contains lymph nodes (Node of Cloquet or Rosenmüller), lymphatics, and areolar tissue.

Q: Which of the following is NOT a flexor of the hip joint?

Gluteus maximus. **Explanation:** The hip joint is a multiaxial ball-and-socket joint where movement is determined by the muscle's position relative to the joint's axis. **Why Gluteus Maximus is the correct answer:** The **Gluteus maximus** is the chief **extensor** of the hip joint, not a flexor. It is located posterior to the joint axis and is particularly active during powerful movements like climbing stairs, running, or rising from a sitting position. It also acts as a lateral rotator of the thigh. **Analysis of incorrect options (Flexors of the Hip):** * **Psoas major:** This is the **primary and most powerful flexor** of the hip. Along with the Iliacus (forming the Iliopsoas), it is essential for lifting the limb during walking. * **Sartorius:** Known as the "tailor's muscle," it is a multi-joint muscle that acts as a flexor, abductor, and lateral rotator of the hip, as well as a flexor of the knee. * **Rectus femoris:** As part of the Quadriceps femoris, it is the only head that crosses the hip joint (originating from the AIIS), making it a potent hip flexor and knee extensor. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Hip Flexor:** Iliopsoas (Psoas major + Iliacus). * **Primary Hip Extensor:** Gluteus maximus. * **Primary Hip Abductor:** Gluteus medius (Trendelenburg sign occurs if paralyzed). * **Nerve Supply:** Gluteus maximus is supplied by the **Inferior Gluteal Nerve (L5, S1, S2)**, while the Gluteus medius and minimus are supplied by the Superior Gluteal Nerve. * **Thomas Test:** Used clinically to assess fixed flexion deformity of the hip.

Q: Which muscle is supplied by the inferior gluteal nerve?

Gluteus maximus. The **inferior gluteal nerve (L5, S1, S2)** is a branch of the sacral plexus that provides motor innervation to only one muscle: the **Gluteus maximus**. This muscle is the largest and most superficial of the gluteal group, acting as the primary extensor of the hip joint. ### Analysis of Options: * **Gluteus maximus (Correct):** It is the sole muscle supplied by the inferior gluteal nerve. It is essential for powerful movements like climbing stairs or rising from a sitting position. * **Obturator externus (Incorrect):** This muscle belongs to the medial compartment of the thigh and is supplied by the **posterior division of the obturator nerve (L3, L4)**. * **Gluteus medius (Incorrect):** Along with the gluteus minimus and tensor fasciae latae, it is supplied by the **superior gluteal nerve (L4, L5, S1)**. * **Quadratus femoris (Incorrect):** This is supplied by its own dedicated nerve, the **nerve to quadratus femoris (L4, L5, S1)**, which also supplies the inferior gemellus. ### High-Yield Clinical Pearls for NEET-PG: * **Trendelenburg Sign:** Damage to the **superior gluteal nerve** leads to paralysis of the gluteus medius and minimus, causing the pelvis to drop on the unsupported (opposite) side during walking. * **Gluteus Maximus Gait:** Damage to the **inferior gluteal nerve** results in difficulty extending the hip. Patients compensate by leaning their trunk backward during the heel-strike phase to maintain balance. * **Nerve Roots:** Remember the "Superior is Higher" rule: Superior gluteal (L4-S1) vs. Inferior gluteal (L5-S2).

Question 1

Locking of the knee joint occurs with all except?

Accepted Answer

Popliteus

Answer

Vastus intermedius

Answer

Vastus medialis

Answer

Rectus femoris

Question 2

Which of the following ligaments prevents hyperextension of the hip?

Accepted Answer

Iliofemoral ligament

Answer

Pubofemoral ligament

Answer

Ischiofemoral ligament

Answer

Ligamentum teres

Question 3

A 75-year-old man is transported to the emergency department with severe pain of his right hip and thigh. A radiographic examination reveals avascular necrosis of the femoral head. Which of the following conditions most likely occurred to produce avascular necrosis in this patient?

Accepted Answer

Intracapsular femoral neck fracture

Answer

Thrombosis of the obturator artery

Answer

Intertrochanteric fracture of the femur

Answer

Comminuted fracture of the extracapsular femoral neck

Question 4

All of the following are true about the popliteal fossa except:

Accepted Answer

The common peroneal nerve passes superficially through the central portion of the popliteal fossa.

Answer

The popliteal fossa is bounded superiorly by the tendons of the hamstring muscles and inferiorly by the two heads of the gastrocnemius muscle.

Answer

The deepest structure in the popliteal fossa is the popliteal artery.

Answer

The popliteal and femoral vessels are continuous through the adductor hiatus.

Question 5

Which of the following muscles has an intracapsular origin?

Accepted Answer

Popliteus

Answer

Plantaris

Answer

Soleus

Answer

Gastrocnemius

Question 6

A 58-year-old female employee of a housecleaning business visits the outpatient clinic with a complaint of constant, burning pain in her knees. Clinical examinations reveal a "housemaid's knee" condition. Which of the following structures is most likely affected?

Accepted Answer

Prepatellar bursa

Answer

Infrapatellar bursa

Answer

Posterior cruciate ligament

Answer

Patellar retinacula

Question 7

The sustentaculum tali is present on which bone?

Accepted Answer

Calcaneus

Answer

Talus

Answer

Navicular

Answer

Cuneiform

Question 8

Which of the following forms the medial boundary of the lacunar ligament?

Accepted Answer

Lacunar ligament

Answer

Inguinal ligament

Answer

Femoral vein

Answer

Pectineus muscle

Question 9

Which of the following is NOT a flexor of the hip joint?

Accepted Answer

Gluteus maximus

Answer

Psoas major

Answer

Sartorius

Answer

Rectus femoris

Question 10

Which muscle is supplied by the inferior gluteal nerve?

Accepted Answer

Gluteus maximus

Answer

Obturator externus

Answer

Gluteus medius

Answer

Quadratus femoris

Lower Limb — MCQs

Lower Limb — MCQs

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