Lower Limb Practice Questions

Q: All of the following muscles are supplied by the tibial component of the sciatic nerve except?

Short head of Biceps femoris. The sciatic nerve (L4-S3) is the largest nerve in the body and consists of two distinct components wrapped in a single connective tissue sheath: the **Tibial nerve** and the **Common Peroneal (Fibular) nerve**. **1. Why the Correct Answer is Right:** The **Short head of Biceps femoris** is the only muscle in the posterior compartment of the thigh that is **not** supplied by the tibial component. Instead, it is supplied by the **Common Peroneal component** of the sciatic nerve. This is a classic anatomical "exception" often tested in exams. **2. Why the Other Options are Incorrect:** The tibial component of the sciatic nerve supplies the "true" hamstring muscles and the hamstring part of the adductor magnus. * **Semitendinosus & Semimembranosus:** These are true hamstring muscles (originating from the ischial tuberosity) and are supplied by the tibial nerve. * **Adductor Magnus:** This is a "hybrid" or "composite" muscle. Its **hamstring part** (ischial part) is supplied by the tibial nerve, while its adductor part is supplied by the obturator nerve. **3. High-Yield Clinical Pearls for NEET-PG:** * **Hybrid Muscles of Lower Limb:** Always remember Adductor Magnus (Obturator + Tibial n.), Pectineus (Femoral + Obturator n.), and Biceps Femoris (Tibial + Common Peroneal n.). * **The "Hamstring" Definition:** To be a true hamstring, a muscle must originate from the ischial tuberosity, insert into a bone of the leg, and be supplied by the tibial nerve. The **short head of biceps femoris fails all three criteria** (originates from linea aspera, supplied by common peroneal n.). * **Sciatic Nerve Bifurcation:** The sciatic nerve typically divides into its two terminal branches at the superior angle of the popliteal fossa.

Q: What is the primary blood supply to the great toe?

Dorsalis pedis artery. The **Dorsalis pedis artery (DPA)** is the primary source of blood supply to the dorsal aspect of the foot and the great toe. It is the direct continuation of the **anterior tibial artery** distal to the level of the malleoli. ### Why Dorsalis Pedis Artery is Correct: The DPA gives off several branches, but its terminal distribution is crucial for the great toe. It provides the **First Dorsal Metatarsal Artery**, which further divides to supply the medial and lateral sides of the great toe (hallux) and the medial side of the second toe. This makes it the dominant arterial supply for the hallux. ### Analysis of Incorrect Options: * **Metatarsal Artery:** While the first dorsal metatarsal artery specifically supplies the great toe, "metatarsal artery" is a general term. The DPA is the parent trunk and the standard answer in clinical anatomy for the primary source. * **Posterior Tibial Artery:** This artery supplies the sole of the foot via the medial and lateral plantar arteries. While it contributes to the plantar digital arteries, the primary landmark for the great toe's supply in standard anatomical teaching (and pulse palpation) is the DPA. ### High-Yield Clinical Pearls for NEET-PG: * **Palpation Point:** The DPA pulse is best felt on the dorsum of the foot, lateral to the tendon of **Extensor Hallucis Longus (EHL)**. * **Clinical Significance:** In Buerger’s disease or Peripheral Arterial Disease (PAD), the DPA pulse is often absent, leading to ischemia of the great toe. * **Arcuate Artery:** This is a branch of the DPA that gives rise to the 2nd, 3rd, and 4th dorsal metatarsal arteries. * **Deep Plantar Artery:** A branch of the DPA that enters the sole between the two heads of the first dorsal interosseous muscle to complete the **plantar arch**.

Q: Third tubercle of the femur provides attachment to which muscle?

Gluteus maximus. ### Explanation The **third tubercle of the femur** (also known as the **gluteal tuberosity**) is a rough, elongated ridge located on the posterior aspect of the proximal femoral shaft, lateral to the pectineal line. It serves as the primary site for the distal insertion of the superficial and inferior fibers of the **Gluteus maximus**. #### Why Option A is Correct: The Gluteus maximus has two main insertions: 1. **Superficial/Superior fibers:** Insert into the **iliotibial tract** (IT band). 2. **Deep/Inferior fibers:** Insert into the **gluteal tuberosity** (third tubercle) of the femur. In some individuals, this tuberosity is significantly enlarged, resembling the third trochanter found in other mammals (like horses). #### Why Other Options are Incorrect: * **B. Gluteus medius:** Inserts onto the lateral surface of the **Greater Trochanter**. * **C. Gluteus minimus:** Inserts onto the anterior surface of the **Greater Trochanter**. * **D. Piriformis:** Inserts onto the apex (superior border) of the **Greater Trochanter**. #### NEET-PG High-Yield Pearls: * **The "Trochanteric" Rule:** Most gluteal muscles and short lateral rotators (Piriformis, Obturators, Gemelli) insert on the **Greater Trochanter**. The Gluteus maximus is the notable exception, inserting lower down on the shaft (gluteal tuberosity). * **Nerve Supply:** Gluteus maximus is the only muscle supplied by the **Inferior Gluteal Nerve (L5, S1, S2)**. * **Clinical Significance:** The Gluteus maximus is the chief extensor of the hip when rising from a sitting position or climbing stairs. Its paralysis results in a "Gluteus Maximus Lurch."

Q: Injury of the common peroneal nerve at the lateral aspect of the head of the fibula results in all of the following except?

Loss of ankle reflex. The **Common Peroneal Nerve (CPN)** is the most frequently injured nerve in the lower limb due to its superficial course as it winds around the **neck of the fibula**. **1. Why "Loss of ankle reflex" is the correct answer:** The ankle reflex (Achilles tendon reflex) tests the **S1 nerve root**. The motor component of this reflex is mediated by the **Tibial nerve**, which innervates the gastrocnemius and soleus muscles (plantarflexors). Since the CPN is a branch of the sciatic nerve distinct from the tibial nerve, an injury at the fibular head will **not** affect the ankle reflex. **2. Analysis of incorrect options:** * **Weakness of ankle dorsiflexion & Foot drop:** The CPN divides into the Deep and Superficial Peroneal nerves. The **Deep Peroneal nerve** supplies the anterior compartment of the leg (tibialis anterior, etc.). Paralysis of these muscles leads to a loss of dorsiflexion, clinically manifesting as **foot drop**. * **Sensory impairment:** The CPN gives off the lateral sural cutaneous nerve, and its branches (Superficial Peroneal nerve) supply the skin of the **lower lateral leg and the dorsum of the foot** (except the first web space, which is deep peroneal, and the lateral border, which is sural). **Clinical Pearls for NEET-PG:** * **Gait:** Patients with CPN injury exhibit a **"High-steppage gait"** to prevent toes from dragging. * **First Web Space:** Sensory loss specifically in the first interdigital cleft indicates isolated **Deep Peroneal Nerve** injury. * **Inversion vs. Eversion:** In CPN injury, **eversion** is lost (Superficial Peroneal), but **inversion** is preserved (Tibial nerve/Tibialis posterior). * **Common Causes:** Tight plaster casts, leg crossing, or fibular neck fractures.

Q: All the following muscles are supplied by the anterior division of the obturator nerve except?

Adductor magnus. **Explanation:** The **obturator nerve (L2–L4)** is the primary nerve of the medial compartment of the thigh. After passing through the obturator canal, it divides into **anterior and posterior divisions**, separated by the adductor brevis muscle. **1. Why Adductor Magnus is the correct answer:** The **Adductor magnus** is a "hybrid" or "composite" muscle with a dual nerve supply. Its **adductor part** is supplied by the **posterior division** of the obturator nerve, while its **hamstring part** is supplied by the **tibial component of the sciatic nerve**. It is never supplied by the anterior division. **2. Analysis of incorrect options (Supplied by the Anterior Division):** * **Adductor longus:** A superficial muscle of the medial compartment, consistently supplied by the anterior division. * **Gracilis:** The most medial muscle of the thigh, supplied by the anterior division. * **Pectineus:** While primarily supplied by the femoral nerve, it frequently receives a branch from the **anterior division** of the obturator nerve (accessory obturator nerve when present). In the context of standard NEET-PG patterns, it is grouped with the anterior division's distribution. **High-Yield Clinical Pearls for NEET-PG:** * **Adductor Brevis:** This muscle acts as the "sandwich filling"; the anterior division runs anterior to it, and the posterior division runs posterior to it. It can be supplied by either or both divisions. * **Obturator Externus:** This is the only muscle supplied by the **trunk** of the obturator nerve (or the posterior division) before it splits significantly. * **Hilton’s Law:** The obturator nerve supplies the hip and knee joints, explaining why hip pathology often presents as referred pain to the medial knee.

Q: During a football game, a 21-year-old wide receiver was illegally blocked by a linebacker, who threw himself against the posterolateral aspect of the runner's left knee. As he lay on the ground, the wide receiver grasped his knee in obvious pain. Which of the following structures is frequently subject to injury from this type of force against the knee?

Anterior cruciate ligament. ### Explanation The clinical scenario describes a classic **"Clipping Injury"** or a blow to the **posterolateral aspect** of the knee. This mechanism of injury results in a force that pushes the femur posteriorly relative to the tibia, or more commonly, creates a **valgus stress** combined with internal rotation. **1. Why the Anterior Cruciate Ligament (ACL) is correct:** The ACL is the primary stabilizer preventing anterior translation of the tibia on the femur. When a force is applied to the posterolateral aspect of the knee, it often results in a **valgus strain**. This puts immense tension on the "Unhappy Triad" (O'Donoghue's Triad), which consists of the **Anterior Cruciate Ligament**, **Medial Collateral Ligament (MCL)**, and the **Medial Meniscus** (though recent studies suggest the lateral meniscus is more commonly injured in acute ACL tears). The ACL is the most frequently ruptured of these structures in contact sports involving sudden deceleration or lateral impact. **2. Why the other options are incorrect:** * **Option A (Fibular collateral ligament):** The FCL (Lateral Collateral Ligament) is injured by a **varus force** (impact to the medial side of the knee), not a lateral/valgus force. * **Option C & D (Posterior Cruciate Ligament):** The PCL is typically injured by a direct blow to the **anterior** aspect of the proximal tibia (e.g., "Dashboard injury") or extreme hyperextension. It is much stronger than the ACL and less likely to be injured by a posterolateral blow. ### NEET-PG High-Yield Pearls: * **Unhappy Triad (O'Donoghue):** ACL + MCL + Medial Meniscus (Classic teaching) or Lateral Meniscus (Modern clinical finding). * **Lachman Test:** The most sensitive clinical test for an acute ACL tear. * **Pivot Shift Test:** Most specific test for ACL deficiency. * **Segond Fracture:** An avulsion fracture of the lateral tibial condyle; it is pathognomonic for an ACL tear.

Q: The deltoid ligament is attached to all of the following except?

Lateral malleolus. **Explanation:** The **Deltoid ligament** (Medial ligament of the ankle) is a strong, triangular-shaped fibrous band located on the **medial side** of the ankle joint. Its primary function is to resist over-eversion of the foot. **1. Why "Lateral Malleolus" is the correct answer:** The lateral malleolus is a feature of the **fibula** on the lateral aspect of the ankle. It serves as the attachment point for the **Lateral Ligament complex** (comprising the Anterior Talofibular, Posterior Talofibular, and Calcaneofibular ligaments). Since the deltoid ligament is strictly a medial structure, it has no attachment to the lateral malleolus. **2. Analysis of incorrect options (Attachments of the Deltoid Ligament):** The deltoid ligament is divided into superficial and deep layers, all originating from the **Medial Malleolus (Option A)** of the tibia. * **Talus (Option B):** The ligament attaches to the talus via the *Anterior Tibiotalar* and *Posterior Tibiotalar* bands. * **Calcaneum (Option C):** The *Tibiocalcaneal* part of the ligament attaches to the **Sustentaculum tali** of the calcaneus. * *Note:* It also attaches to the **Navicular bone** via the *Tibionavicular* part. **Clinical Pearls for NEET-PG:** * **Strength:** The deltoid ligament is significantly stronger than the lateral ligaments; therefore, eversion sprains often result in an **avulsion fracture** of the medial malleolus rather than a ligamentous tear. * **Spring Ligament:** The deltoid ligament blends with the plantar calcaneonavicular (spring) ligament, helping to support the medial longitudinal arch of the foot. * **Stability:** It is the primary stabilizer of the talar shift.

Question 1

A 32-year-old man presents with multiple tendinous tears in his foot after an injury. Which of the following bones is associated with the muscles involved in these tears?

Accepted Answer

Calcaneus

Answer

Navicular

Answer

Cuboid

Answer

Sustentaculum tali

Question 2

All of the following muscles are supplied by the tibial component of the sciatic nerve except?

Accepted Answer

Short head of Biceps femoris

Answer

Adductor magnus

Answer

Semimembranosus

Answer

Semitendinosus

Question 3

Which of the following movements would be affected in case of paralysis of the quadriceps femoris muscle?

Accepted Answer

Extension at the knee

Answer

Adduction at the hip

Answer

Extension at the hip

Answer

Flexion at the knee

Question 4

What is the primary blood supply to the great toe?

Accepted Answer

Dorsalis pedis artery

Answer

Metatarsal artery

Answer

Posterior tibial artery

Question 5

Third tubercle of the femur provides attachment to which muscle?

Accepted Answer

Gluteus maximus

Answer

Gluteus medius

Answer

Gluteus minimis

Answer

Piriformis

Question 6

Which nerve is affected in the Trendelenburg test?

Accepted Answer

Superior gluteal nerve

Answer

Inferior gluteal nerve

Answer

Obturator nerve

Answer

Pudendal nerve

Question 7

Injury of the common peroneal nerve at the lateral aspect of the head of the fibula results in all of the following except?

Accepted Answer

Loss of ankle reflex

Answer

Weakness of ankle dorsiflexion

Answer

Foot drop

Answer

Sensory impairment on the lateral aspect of the leg extending to the dorsum of the foot

Question 8

All the following muscles are supplied by the anterior division of the obturator nerve except?

Accepted Answer

Adductor magnus

Answer

Pectineus

Answer

Adductor longus

Answer

Gracilis

Question 9

During a football game, a 21-year-old wide receiver was illegally blocked by a linebacker, who threw himself against the posterolateral aspect of the runner's left knee. As he lay on the ground, the wide receiver grasped his knee in obvious pain. Which of the following structures is frequently subject to injury from this type of force against the knee?

Accepted Answer

Anterior cruciate ligament

Answer

Fibular collateral ligament

Answer

Lateral meniscus and posterior cruciate ligament

Answer

Fibular collateral and posterior cruciate ligament

Question 10

The deltoid ligament is attached to all of the following except?

Accepted Answer

Lateral malleolus

Answer

Medial malleolus

Answer

Talus

Answer

Calcaneum

Lower Limb — MCQs

Lower Limb — MCQs

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