Lower Limb Practice Questions

Q: Inversion of the foot is produced by which of the following muscles?

Tibialis anterior. **Explanation:** The movements of inversion and eversion occur primarily at the **subtalar** and **transverse tarsal joints**. Inversion is the movement where the sole of the foot faces medially. **Why Tibialis Anterior is Correct:** The **Tibialis anterior** (supplied by the Deep Peroneal Nerve) is a primary inverter of the foot. It inserts into the medial cuneiform and the base of the first metatarsal. Because its tendon passes medial to the axis of the subtalar joint, its contraction pulls the medial border of the foot upwards and inwards. It also acts as the chief dorsiflexor of the ankle. **Analysis of Incorrect Options:** * **Peroneus longus:** This muscle is a primary **everter** of the foot and a weak plantarflexor. It inserts on the lateral side of the medial cuneiform and first metatarsal, pulling the lateral border of the foot upwards. * **Soleus:** This is a powerful **plantarflexor** of the ankle joint. It does not cross the tarsal joints in a way that significantly contributes to inversion or eversion. * **Popliteus:** This muscle acts on the **knee joint**. It "unlocks" the knee by laterally rotating the femur on the fixed tibia (or medially rotating the tibia in a non-weight-bearing position). It has no action on the foot. **High-Yield Clinical Pearls for NEET-PG:** * **The "Tibialis" Rule:** Both Tibialis muscles (**Anterior and Posterior**) are **Inverters**. * **The "Peroneus" Rule:** All Peroneal muscles (**Longus, Brevis, and Tertius**) are **Everters**. * **Nerve Supply:** Injury to the **Common Peroneal Nerve** leads to loss of eversion and dorsiflexion, resulting in **Foot Drop** and a characteristic "Equinovarus" position (the foot remains inverted due to the unopposed action of Tibialis posterior).

Q: Identify the muscle that is not in relation with the structure marked A.

Gluteus maximus. ***Gluteus maximus*** - The **gluteus maximus** does not insert into the **greater trochanter** but instead inserts into the **gluteal tuberosity** of the femur and the **iliotibial tract**. - It is the largest gluteal muscle responsible for **hip extension** and **external rotation**, but has no direct relation to the greater trochanter. *Gluteus medius* - The **gluteus medius** inserts directly into the **lateral surface of the greater trochanter**, making it closely related to structure A. - This muscle is crucial for **hip abduction** and **pelvic stabilization** during walking, with its insertion site being the greater trochanter. *Gluteus minimus* - The **gluteus minimus** inserts into the **anterior aspect of the greater trochanter**, establishing a direct anatomical relationship with structure A. - It works synergistically with gluteus medius for **hip abduction** and **medial rotation** of the thigh. *Piriformis* - The **piriformis muscle** inserts into the **superior border of the greater trochanter**, making it anatomically related to structure A. - This deep muscle is important for **hip external rotation** and **hip stabilization**, with its insertion directly on the greater trochanter.

Q: What is the origin of the Posterior Cruciate Ligament (PCL)?

Posterior part of the intercondylar area of the tibia. The **Posterior Cruciate Ligament (PCL)** is one of the two major intra-articular ligaments of the knee, essential for maintaining posterior stability. ### **Explanation of the Correct Answer** **Option A** is correct because the PCL originates from the **posterior part of the intercondylar area of the tibia**, specifically from a depression behind the intercondylar eminence. From this tibial attachment, it passes upwards, forwards, and medially to insert into the **anterolateral aspect of the medial femoral condyle**. Its primary function is to prevent the tibia from sliding posteriorly relative to the femur. ### **Analysis of Incorrect Options** * **Option B:** The anterior part of the intercondylar area of the tibia is the site of origin for the **Anterior Cruciate Ligament (ACL)**. * **Option C & D:** These options refer to the **insertion** points on the femur, not the origin. The PCL inserts onto the lateral surface of the medial femoral condyle. A common mnemonic to remember the femoral insertions is **LAMP**: **L**ateral condyle = **A**CL; **M**edial condyle = **P**CL. ### **NEET-PG High-Yield Pearls** * **Strength:** The PCL is thicker and stronger than the ACL. * **Blood Supply:** Both cruciate ligaments are supplied by the **middle genicular artery** (branch of the popliteal artery). * **Clinical Sign:** Injury to the PCL results in a **Positive Posterior Drawer Sign** or "Sag sign." * **Mechanism of Injury:** Often occurs due to a direct blow to the proximal tibia while the knee is flexed (e.g., **"Dashboard injury"** in motor vehicle accidents).

Q: The obturator nerve innervates all of the following muscles except?

Obturator internus. **Explanation:** The **obturator nerve (L2–L4)** is the primary nerve of the medial compartment of the thigh. It supplies the adductor group of muscles and the obturator externus. **Why Obturator Internus is the correct answer:** Despite its similar name, the **Obturator internus** is a muscle of the gluteal region, not the medial thigh. It is innervated by the **Nerve to Obturator Internus (L5, S1, S2)**, which arises from the sacral plexus. This is a common "trap" in anatomy exams due to the nomenclature. **Analysis of Incorrect Options:** * **Adductor longus:** This is a classic medial compartment muscle supplied by the anterior division of the obturator nerve. * **Pectineus:** This is a "hybrid" or "composite" muscle. While it is primarily supplied by the **femoral nerve**, it frequently receives a small contribution from the **obturator nerve** (accessory obturator nerve). In the context of this question, it is considered part of the obturator's distribution compared to the obturator internus, which has a completely different nerve origin. * **Obturator externus:** This muscle is supplied by the posterior division of the obturator nerve. It is the only external rotator of the hip supplied by this nerve. **High-Yield Clinical Pearls for NEET-PG:** 1. **Hybrid Muscles of Lower Limb:** * **Adductor Magnus:** Obturator nerve (adductor part) and Sciatic nerve/Tibial component (hamstring part). * **Pectineus:** Femoral nerve and Obturator nerve. 2. **Referred Pain:** Irritation of the obturator nerve (e.g., in ovarian cancer or obturator hernia) can cause referred pain to the medial side of the knee (Howship-Romberg sign). 3. **Obturator Externus:** It is the "key" to the medial compartment, and the obturator nerve divisions (anterior and posterior) pass around it.

Q: A 45-year-old male presents with fractures of the tibia and fibula after a bicycle fall. On physical examination, he has a foot drop but normal foot eversion. Which of the following nerves is most likely injured?

Deep fibular nerve. ### **Explanation** The clinical presentation of **foot drop** with **preserved eversion** is the diagnostic key to this question. **1. Why the Deep Fibular Nerve is Correct:** The common fibular nerve (CFN) bifurcates into the superficial and deep fibular nerves. The **deep fibular nerve** innervates the muscles of the **anterior compartment** of the leg (Tibialis anterior, Extensor digitorum longus, Extensor hallucis longus). The Tibialis anterior is the primary dorsiflexor of the foot; its paralysis leads to **foot drop**. Since the superficial fibular nerve remains intact, the muscles of the lateral compartment (fibularis longus and brevis) can still perform **eversion**, which matches the patient's presentation. **2. Why the Other Options are Incorrect:** * **Tibial Nerve:** This nerve innervates the posterior compartment (plantarflexors). Injury would result in an inability to plantarflex the foot ("heel walk" deficit) and loss of sensation on the sole, not foot drop. * **Common Fibular Nerve:** Injury here (typically at the neck of the fibula) would cause **both** foot drop (deep branch) and loss of eversion (superficial branch), along with sensory loss in the first web space and lateral leg. * **Superficial Fibular Nerve:** This nerve supplies the lateral compartment. Injury would cause a loss of eversion, but dorsiflexion (and thus foot drop) would be unaffected. **3. Clinical Pearls for NEET-PG:** * **Deep Fibular Nerve:** Supplies the **first interdigital cleft** (web space) for sensation. This is the most high-yield sensory landmark. * **Common Fibular Nerve:** The most commonly injured nerve in the lower limb due to its superficial course around the **fibular neck**. * **Mnemonic for Gait:** **PED** (**P**eroneal **E**verts and **D**orsiflexes; if injured, the foot drops) vs. **TIP** (**T**ibial **I**nverts and **P**lantarflexes; if injured, you cannot stand on your toes).

Q: What is the nerve supply of the obturator internus muscle?

L5-S2. The **Obturator Internus** is a key lateral rotator of the hip. It is supplied by the **Nerve to Obturator Internus**, which arises from the **sacral plexus** with root values **L5, S1, and S2**. **Why C is correct:** The nerve to obturator internus originates from the ventral rami of L5-S2. A high-yield anatomical fact is its unique course: it leaves the pelvis through the **greater sciatic foramen**, passes over the ischial spine (lateral to the internal pudendal vessels), and re-enters the pelvis through the **lesser sciatic foramen** to supply the muscle on its pelvic surface. It also supplies the **Superior Gemellus** muscle. **Why incorrect options are wrong:** * **A (L1-L3):** These roots contribute to the lumbar plexus (e.g., femoral and obturator nerves). The obturator nerve (L2-L4) supplies the adductor compartment, not the obturator internus. * **B (L4-S1):** This is the root value for the **Superior Gluteal Nerve** (supplying gluteus medius/minimus) and the **Nerve to Quadratus Femoris** (which also supplies the Inferior Gemellus). * **D (S1-S3):** This range is more characteristic of the **Posterior Cutaneous Nerve of the Thigh** (S1-S3) or the **Pudendal Nerve** (S2-S4). **High-Yield Clinical Pearls for NEET-PG:** * **The "Triceps Coxae":** The Obturator Internus, Superior Gemellus, and Inferior Gemellus function together; however, they have different nerve supplies (Nerve to Obturator Internus for the first two; Nerve to Quadratus Femoris for the third). * **Exit/Entry:** The Nerve to Obturator Internus is one of the structures that exits the greater and enters the lesser sciatic foramen. * **Action:** It is a powerful lateral rotator of the extended thigh and an abductor of the flexed thigh.

Q: Which tarsal bone articulates with the tibia and fibula?

talus. The **talus** is the correct answer because it is the only tarsal bone that articulates with the leg bones (tibia and fibula) to form the **ankle joint (talocrural joint)**. The superior surface of the talus, known as the **trochlea**, is wedge-shaped and fits into the mortise formed by the medial malleolus (tibia), the lateral malleolus (fibula), and the inferior surface of the tibia. This articulation is primarily responsible for dorsiflexion and plantarflexion of the foot. **Why other options are incorrect:** * **Calcaneus:** This is the largest tarsal bone (heel bone). It articulates superiorly with the talus (subtalar joint) and anteriorly with the cuboid, but it has no direct contact with the tibia or fibula. * **Cuboid:** Located on the lateral aspect of the foot, it articulates with the calcaneus, the lateral cuneiform, and the 4th and 5th metatarsals. * **Navicular:** Positioned on the medial side between the talus and the three cuneiform bones. It does not reach the ankle joint complex. **Clinical Pearls for NEET-PG:** 1. **No Muscular Attachments:** The talus is unique because **no muscles or tendons** originate from or insert onto it. Its position is maintained entirely by ligaments and bony articulations. 2. **Blood Supply:** The blood supply to the talus is retrograde (from distal to proximal), primarily via the **artery of the tarsal canal** (branch of the posterior tibial artery). 3. **Avascular Necrosis (AVN):** Due to its precarious blood supply, fractures of the **talar neck** (Hawkins classification) carry a high risk of AVN. 4. **Subtalar Joint:** Inversion and eversion of the foot occur at the subtalar and transverse tarsal joints, not at the ankle joint.

Question 1

Inversion of the foot is produced by which of the following muscles?

Accepted Answer

Tibialis anterior

Answer

Peroneus longus

Answer

Soleus

Answer

Popliteus

Question 2

Which of the following forms the tendinous sling in the superficial arch of the foot?

Accepted Answer

Peroneus longus and tibialis posterior

Answer

Peroneus longus and peroneus brevis

Answer

Peroneus longus and flexor hallucis longus

Answer

Peronius brevis and tibialis posterior

Question 3

Tibialis posterior has insertion to all of the following bones except?

Accepted Answer

1st metatarsal

Answer

2nd metatarsal

Answer

Medial Cuneiform

Answer

3rd Metatarsal

Question 4

Identify the muscle that is not in relation with the structure marked A.

Accepted Answer

Gluteus maximus

Answer

Gluteus medius

Answer

Gluteus minimus

Answer

Piriformis

Question 5

During the surgical repair of a femoral hernia, which structure is most vulnerable to major injury?

Accepted Answer

Laterally

Answer

Anteriorly

Answer

Posteriorly

Answer

Medially

Question 6

What is the origin of the Posterior Cruciate Ligament (PCL)?

Accepted Answer

Posterior part of the intercondylar area of the tibia

Answer

Anterior part of the intercondylar area of the tibia

Answer

Medial part of the medial femoral condyle

Answer

Lateral part of the medial femoral condyle

Question 7

The obturator nerve innervates all of the following muscles except?

Accepted Answer

Obturator internus

Answer

Adductor longus

Answer

Pectineus

Answer

Obturator externus

Question 8

A 45-year-old male presents with fractures of the tibia and fibula after a bicycle fall. On physical examination, he has a foot drop but normal foot eversion. Which of the following nerves is most likely injured?

Accepted Answer

Deep fibular nerve

Answer

Tibial nerve

Answer

Common fibular nerve

Answer

Superficial fibular nerve

Question 9

What is the nerve supply of the obturator internus muscle?

Accepted Answer

L5-S2

Answer

L1-L3

Answer

L4-S1

Answer

S1-S3

Question 10

Which tarsal bone articulates with the tibia and fibula?

Accepted Answer

talus

Answer

calcaneus

Answer

cuboid

Answer

navicular

Lower Limb — MCQs

Lower Limb — MCQs

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