Lower Limb Practice Questions

Q: Which muscles are collectively known as 'Triceps surae'?

Gastrocnemius and soleus. ### Explanation **Concept Overview:** The term **Triceps surae** (Latin for "three-headed muscle of the calf") refers to a pair of muscles located in the superficial posterior compartment of the leg. It is composed of the **two heads of the Gastrocnemius** (medial and lateral) and the **single head of the Soleus**. These muscles share a common insertion point via the **Tendo calcaneus (Achilles tendon)** onto the posterior surface of the calcaneum. **Why Option A is Correct:** * **Gastrocnemius:** A two-headed, superficial muscle that crosses both the knee and ankle joints. * **Soleus:** A broad, flat muscle lying deep to the gastrocnemius. It is often called the "Peripheral Heart" because its venous sinuses are crucial for pumping blood back to the heart against gravity. * Together, they act as the primary **plantar flexors** of the foot. **Why Other Options are Incorrect:** * **B. Popliteus:** This is a deep muscle of the posterior compartment known as the "Key of the knee" because it unlocks the knee joint by rotating the femur laterally on a fixed tibia. * **C & D. Extensor hallucis longus & Extensor digitorum longus:** These are muscles of the **anterior compartment** of the leg. They are responsible for dorsiflexion of the foot and extension of the toes, not plantar flexion. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Supply:** All muscles of the posterior compartment, including the triceps surae, are supplied by the **Tibial nerve (S1, S2)**. * **Achilles Tendon Reflex:** Tests the **S1-S2** nerve roots. * **Plantaris:** Often called the "Freshman’s Nerve," it is a vestigial muscle located between the gastrocnemius and soleus; its tendon is a common graft source for reconstructive surgery. * **Soleus Fact:** Unlike the gastrocnemius, the soleus is a **multipennate** muscle and consists predominantly of slow-twitch (Type I) muscle fibers, making it highly resistant to fatigue.

Q: Which of the following does NOT supply the femoral head?

Profunda femoris artery. The blood supply to the femoral head is a high-yield topic in Anatomy and Orthopaedics, primarily because of its clinical relevance in femoral neck fractures and avascular necrosis (AVN). ### **Explanation** The femoral head receives its blood supply from three main sources: the **Medial Circumflex Femoral Artery (MCFA)**, the **Lateral Circumflex Femoral Artery (LCFA)**, and the **Artery of Ligamentum Teres**. While the **Profunda Femoris Artery** is the parent vessel that gives rise to the circumflex arteries, it does not directly supply the femoral head itself. * **Option C (Correct):** The Profunda femoris artery provides the branches (MCFA and LCFA) that form the extracapsular arterial ring, but the main trunk of the artery continues down the thigh to supply the musculature via perforating branches. It has no direct distribution to the femoral head. ### **Analysis of Other Options** * **Option A (MCFA):** This is the **most important** source. Its retinacular branches (especially the posterosuperior group) provide the bulk of the blood supply to the femoral head. * **Option B (LCFA):** It contributes to the extracapsular arterial ring at the base of the neck. Its branches must traverse the thick anterior capsule, making it less significant than the MCFA. * **Option C (Artery of Ligamentum Teres):** A branch of the **obturator artery**, it supplies a small area around the fovea centralis. While vital in children, its contribution diminishes in adults. ### **NEET-PG High-Yield Pearls** 1. **Crucial Vessel:** The **Medial Circumflex Femoral Artery** is the primary source of blood; damage to this vessel in intracapsular fractures leads to **Avascular Necrosis (AVN)**. 2. **Anastomosis:** The extracapsular ring is formed by the MCFA (posteriorly) and LCFA (anteriorly). 3. **Pediatric Note:** In children, the artery of the ligamentum teres is more significant as the epiphyseal plate acts as a barrier to the retinacular vessels.

Q: Obturator nerve arises from which spinal nerve roots?

Ventral divisions of L2, L3, L4. ### Explanation The **Obturator nerve** is a major branch of the lumbar plexus. It is formed within the psoas major muscle by the fusion of the **ventral (anterior) divisions of the ventral rami of L2, L3, and L4** spinal nerves. **1. Why Option A is Correct:** The lumbar plexus is formed by the ventral rami of L1–L4. These rami split into anterior (ventral) and posterior (dorsal) divisions. The **Obturator nerve** arises from the **ventral divisions**, which typically supply the adductor (pre-axial) compartment of the thigh. **2. Why the other options are incorrect:** * **Option B:** The **dorsal divisions** of L2, L3, and L4 join to form the **Femoral nerve**. This is a common point of confusion; remember: *Ventral = Obturator, Dorsal = Femoral.* * **Options C & D:** The L1 and L2 roots contribute to the Iliohypogastric, Ilioinguinal (L1), and Genitofemoral (L1, L2) nerves, but not the obturator nerve. **Clinical Pearls & High-Yield Facts for NEET-PG:** * **Course:** It emerges from the medial border of the psoas major and enters the thigh through the **obturator canal**. * **Supply:** It provides motor innervation to the **adductor group** (Adductor longus, brevis, magnus, and gracilis) and sensory innervation to the medial aspect of the thigh. * **Howship-Romberg Sign:** Pain down the medial aspect of the thigh due to compression of the obturator nerve (often by an obturator hernia). * **Referred Pain:** Since the obturator nerve supplies both the **hip and knee joints** (Hilton’s Law), pathology in the hip (like Perthes disease) often presents as referred pain to the medial knee.

Q: The saphenous vein is a tributary of which of the following veins?

Lateral marginal vein. The **Small Saphenous Vein (SSV)** is formed by the union of the **lateral marginal vein** of the foot and the lateral end of the dorsal venous arch [1]. It travels posterior to the lateral malleolus, ascends along the midline of the calf, and typically terminates by piercing the popliteal fascia to drain into the **popliteal vein**. **Analysis of Options:** * **B. Lateral marginal vein (Correct):** The small saphenous vein is the direct upward continuation of the lateral marginal vein [1]. * **A. Medial marginal vein:** This vein continues as the **Great Saphenous Vein (GSV)**, passing anterior to the medial malleolus [2]. * **C. Posterior tibial vein:** This is a deep vein of the leg. While the SSV has communicating branches to deep veins, it is not a tributary of the posterior tibial vein. * **D. Dorsal venous arch:** While the SSV originates at the lateral end of this arch, it is specifically defined as the continuation of the lateral marginal vein. **High-Yield NEET-PG Pearls:** * **Course:** SSV is accompanied by the **Sural nerve** in the leg (Clinical: Nerve injury during vein stripping leads to loss of sensation on the lateral aspect of the foot). * **Termination:** The most common site of termination is the Popliteal vein, but it can occasionally drain into the GSV or deep femoral veins (Giacomini vein) [1]. * **Valves:** The SSV contains approximately 7–13 valves to prevent backflow. * **Position:** SSV is **posterior** to the lateral malleolus; GSV is **anterior** to the medial malleolus [2].

Q: What is the nerve supply of the Tibialis anterior muscle?

Deep peroneal nerve. **Explanation:** The **Tibialis anterior** is the most medial muscle of the **anterior compartment of the leg**. Muscles in this compartment are primarily responsible for dorsiflexion of the foot and extension of the toes. 1. **Why the Correct Answer is Right:** The **Deep Peroneal Nerve** (L4, L5) is the nerve of the anterior compartment of the leg. It arises from the common peroneal nerve at the neck of the fibula. It supplies all muscles in this compartment: Tibialis anterior, Extensor digitorum longus, Extensor hallucis longus, and Peroneus tertius. The Tibialis anterior specifically acts as the primary dorsiflexor and invertor of the foot. 2. **Why the Incorrect Options are Wrong:** * **Tibial nerve:** This nerve supplies the **posterior compartment** of the leg (e.g., Gastrocnemius, Soleus, Tibialis posterior). Its primary functions are plantarflexion and toe flexion. * **Femoral nerve:** This nerve supplies the **anterior compartment of the thigh** (e.g., Quadriceps femoris), facilitating hip flexion and knee extension. * **Sural nerve:** This is a **purely sensory nerve** formed by branches of the tibial and common peroneal nerves. It supplies the skin of the lateral and posterior part of the lower third of the leg and the lateral border of the foot. **Clinical Pearls & High-Yield Facts:** * **Foot Drop:** Injury to the Common Peroneal Nerve (at the fibular neck) or the Deep Peroneal Nerve leads to paralysis of the Tibialis anterior, resulting in "Foot Drop" and a "High-steppage gait." * **Anterior Compartment Syndrome:** The Tibialis anterior is the muscle most commonly involved in this surgical emergency, which can lead to ischemic necrosis and deep peroneal nerve palsy. * **Inversion vs. Eversion:** While Tibialis anterior (Deep Peroneal Nerve) and Tibialis posterior (Tibial Nerve) both **invert** the foot, they have opposite actions on the ankle joint (Dorsiflexion vs. Plantarflexion).

Q: What is true about the cuboid bone?

It articulates with the calcaneus.. **Explanation:** The **cuboid bone** is one of the seven tarsal bones located on the lateral aspect of the foot. It plays a crucial role in maintaining the lateral longitudinal arch. **1. Why Option D is Correct:** The cuboid articulates proximally with the **calcaneus** at the calcaneocuboid joint. This joint is a part of the midtarsal (transverse tarsal) joint complex. Distally, it articulates with the 4th and 5th metatarsals, and medially with the lateral cuneiform and occasionally the navicular. **2. Why the Other Options are Incorrect:** * **Option A:** Like all tarsal bones, the cuboid develops via **endochondral ossification** (ossification within a cartilage model), not membranous ossification. * **Option B:** The **lunate** is a carpal bone found in the wrist, not the foot. The cuboid articulates proximally with the calcaneus. * **Option C:** The flexor retinaculum of the foot (laciniate ligament) attaches to the medial malleolus and the calcaneus. It is the **peroneal retinaculum** and the **long plantar ligament** that have attachments related to the cuboid. **3. High-Yield Clinical Pearls for NEET-PG:** * **Ossification:** The cuboid is often the only tarsal bone (besides the calcaneus and talus) to have an ossification center present at **birth**. This is a key radiological marker for assessing fetal maturity. * **Peroneal Groove:** The plantar surface of the cuboid contains a deep groove for the tendon of the **peroneus longus** muscle. * **Nutcracker Fracture:** A compression fracture of the cuboid between the calcaneus and the metatarsals is colloquially known as a "Nutcracker fracture."

Q: Which nerve supplies the adductor compartment of the thigh?

Obturator nerve. The **obturator nerve** is the primary motor nerve of the **medial (adductor) compartment** of the thigh. Arising from the ventral rami of **L2, L3, and L4** (lumbar plexus), it enters the thigh through the obturator canal. It supplies all muscles in this compartment, including the adductor longus, adductor brevis, gracilis, and obturator externus. **Analysis of Options:** * **Femoral Nerve (L2-L4):** This is the nerve of the **anterior (extensor) compartment** of the thigh. It supplies the quadriceps femoris, sartorius, and pectineus. * **Superior Gluteal Nerve (L4-S1):** This nerve supplies the gluteus medius, gluteus minimus, and tensor fasciae latae. Its primary function is hip abduction and stabilization. * **Inferior Gluteal Nerve (L5-S2):** This nerve exclusively supplies the **gluteus maximus**, the chief extensor of the hip. **High-Yield Clinical Pearls for NEET-PG:** * **The "Hybrid" Muscle:** The **Adductor Magnus** has a dual nerve supply. Its adductor part is supplied by the **obturator nerve**, while its "hamstring" part is supplied by the **tibial component of the sciatic nerve**. * **Pectineus:** Often considered a transitional muscle, it is located in the medial compartment but is typically supplied by the **femoral nerve** (though it may occasionally receive a branch from the obturator). * **Howship-Romberg Sign:** Pain or numbness on the medial aspect of the thigh due to compression of the obturator nerve (often by an obturator hernia). * **Referred Pain:** Because the obturator nerve also provides sensory innervation to the hip and knee joints, pathology in the hip (like Perthes disease) often presents as referred pain to the medial knee.

Q: A patient sustained a hyperextension injury to the knee. Which of the following ligaments prevents excessive anterior gliding of the femur on the tibia?

Posterior cruciate ligament. ### Explanation The **Posterior Cruciate Ligament (PCL)** is the strongest ligament of the knee. Its primary biomechanical function is to prevent **posterior displacement of the tibia relative to the femur**. Conversely, this can be described as preventing **anterior gliding of the femur on the tibia**, especially when the knee is weight-bearing and flexed. During hyperextension injuries, the PCL is the primary structure that resists the posterior displacement of the tibia, making it the correct answer. #### Analysis of Options: * **Posterior Cruciate Ligament (PCL):** It originates from the lateral surface of the medial condyle of the femur and attaches to the posterior intercondylar area of the tibia. It prevents the femur from sliding forward off the tibial plateau during weight-bearing. * **Anterior Cruciate Ligament (ACL):** This ligament prevents **anterior displacement of the tibia on the femur** (or posterior gliding of the femur on the tibia). It is most commonly injured during non-contact pivoting or sudden deceleration. * **Medial Collateral Ligament (MCL):** Its primary role is to resist **valgus (abduction) stress** at the knee. * **Lateral Collateral Ligament (LCL):** Its primary role is to resist **varus (adduction) stress** at the knee. #### High-Yield Clinical Pearls for NEET-PG: * **PCL Injury Sign:** The **"Sag Sign"** or **Posterior Drawer Test** is used to diagnose PCL deficiency. * **ACL vs. PCL:** Remember the mnemonic **"PAM"** (PCL attaches to Medial condyle) and **"APL"** (ACL attaches to Lateral condyle) for their femoral attachments. * **Unhappy Triad (O'Donoghue):** Involves injury to the ACL, MCL, and Medial Meniscus (though modern studies suggest the Lateral Meniscus is more commonly injured in acute phases). * **Blood Supply:** The cruciate ligaments are supplied by the **middle genicular artery**, a branch of the popliteal artery.

Q: A 20-year-old male suffered trauma to his right leg while playing football and did not seek medical attention initially. The affected area became painful, red, and tender. A few days later, he noticed he had to drag the affected foot, and examination revealed a loss of eversion along with foot drop, consistent with injury to the common fibular nerve as it winds around the neck of the fibula. Which of the labeled muscles in the image is fibularis (peroneus) longus?

Muscle A. Muscle A: Fibularis (Peroneus) Longus — supplied by the superficial fibular nerve (a branch of the common fibular nerve); primary actions are eversion of the foot and plantarflexion. Fibularis longus is the most superficial muscle of the lateral compartment, originating from the upper two-thirds of the lateral surface of the fibula, and is the muscle labeled A in the image. The identities of Muscles B, C, and D as depicted in the image should be confirmed against the anatomical positions shown; the lateral compartment contains fibularis longus (A) and fibularis brevis, while the anterior compartment contains tibialis anterior and extensor digitorum longus. In a common fibular nerve lesion, both the superficial and deep fibular nerve branches are affected, causing loss of eversion (superficial fibular nerve) and foot drop/loss of dorsiflexion (deep fibular nerve). Muscle A (Fibularis Longus) is the largest and most superficial of the lateral-compartment evertors and is the muscle labeled A in the image.

Q: What is the chief extensor of the knee joint during hip flexion?

Rectus femoris. **Explanation:** The **Rectus femoris** is the correct answer because it is the only component of the quadriceps femoris muscle group that is **bi-articular** (crosses two joints). It originates from the Anterior Inferior Iliac Spine (AIIS) and the groove above the acetabulum, allowing it to act on both the hip and the knee. **Why Rectus Femoris is correct:** While all four heads of the quadriceps extend the knee, the Rectus femoris is uniquely positioned to extend the knee while the hip is flexed (e.g., during the preparatory phase of kicking a ball). According to Starling’s law of muscle contraction, a muscle is most effective when stretched. When the hip is extended, the Rectus femoris is stretched, but when the hip is flexed, it becomes the primary driver of knee extension to maintain power, as the vasti muscles are purely mono-articular. **Why other options are incorrect:** * **Vastus medialis & Vastus lateralis:** These are mono-articular muscles originating from the femur. They only act on the knee joint and their action is independent of the position of the hip joint. * **Hamstrings:** These are primarily flexors of the knee and extensors of the hip. They are antagonists to the action described in the question. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Supply:** All quadriceps muscles are supplied by the **Femoral Nerve (L2-L4)**. * **Kicking Muscle:** Rectus femoris is often referred to as the "kicking muscle." * **Vastus Medialis Obliquus (VMO):** This specific part of the vastus medialis is crucial for the patellar alignment and prevents lateral dislocation of the patella. * **Clinical Sign:** Avulsion of the AIIS typically involves the origin of the Rectus femoris, common in young athletes.

Question 1

Which muscles are collectively known as 'Triceps surae'?

Accepted Answer

Gastrocnemius and soleus

Answer

Popliteus

Answer

Extensor hallucis longus

Answer

Extensor digitorum longus

Question 2

Which of the following does NOT supply the femoral head?

Accepted Answer

Profunda femoris artery

Answer

Medial circumflex artery

Answer

Lateral circumflex artery

Answer

Artery of the ligamentum teres

Question 3

Obturator nerve arises from which spinal nerve roots?

Accepted Answer

Ventral divisions of L2, L3, L4

Answer

Dorsal divisions of L2, L3, L4

Answer

Ventral rami of L1, L2

Answer

Dorsal rami of L1, L2

Question 4

The saphenous vein is a tributary of which of the following veins?

Accepted Answer

Lateral marginal vein

Answer

Medial marginal vein

Answer

Posterior tibial vein

Answer

Dorsal venous arch

Question 5

What is the nerve supply of the Tibialis anterior muscle?

Accepted Answer

Deep peroneal nerve

Answer

Tibial nerve

Answer

Femoral nerve

Answer

Sural nerve

Question 6

What is true about the cuboid bone?

Accepted Answer

It articulates with the calcaneus.

Answer

It develops by membranous ossification.

Answer

It articulates proximally with the lunate bone.

Answer

The flexor retinaculum is attached to it.

Question 7

Which nerve supplies the adductor compartment of the thigh?

Accepted Answer

Obturator nerve

Answer

Femoral nerve

Answer

Superior gluteal nerve

Answer

Inferior gluteal nerve

Question 8

A patient sustained a hyperextension injury to the knee. Which of the following ligaments prevents excessive anterior gliding of the femur on the tibia?

Accepted Answer

Posterior cruciate ligament

Answer

Anterior cruciate ligament

Answer

Medial collateral ligament

Answer

Lateral collateral ligament

Question 9

A 20-year-old male suffered trauma to his right leg while playing football and did not seek medical attention initially. The affected area became painful, red, and tender. A few days later, he noticed he had to drag the affected foot, and examination revealed a loss of eversion along with foot drop, consistent with injury to the common fibular nerve as it winds around the neck of the fibula. Which of the labeled muscles in the image is fibularis (peroneus) longus?

Accepted Answer

Muscle A

Answer

Muscle C

Answer

Muscle B

Answer

Muscle D

Question 10

What is the chief extensor of the knee joint during hip flexion?

Accepted Answer

Rectus femoris

Answer

Vastus medialis

Answer

Vastus lateralis

Answer

Hamstrings

Lower Limb — MCQs

Lower Limb — MCQs

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