Lower Limb Practice Questions

Q: The involvement of the L5 Nerve Root can affect all of the following movements, except?

Adduction of the thigh. ### Explanation The correct answer is **A. Adduction of the thigh**. The **L5 nerve root** provides motor innervation to several muscle groups in the lower limb, primarily those involved in hip abduction, knee flexion, and movements of the foot and toes. **1. Why Adduction of the Thigh is the correct answer:** Thigh adduction is primarily performed by the Adductor group (Adductor longus, brevis, and magnus), which is innervated by the **Obturator nerve**. The root value for these muscles is **L2, L3, and L4**. Since L5 does not contribute to the obturator nerve's motor supply to the adductors, it is the movement least affected by an L5 lesion. **2. Analysis of Incorrect Options:** * **Flexion of the knee:** This is performed by the Hamstrings. While primarily S1, the hamstrings (specifically the semitendinosus and semimembranosus) receive significant innervation from **L5**. * **Extension of the great toe:** This is the **"classic" L5 test**. The Extensor Hallucis Longus (EHL) is almost exclusively supplied by the **L5** nerve root via the deep peroneal nerve. * **Plantarflexion of the foot:** While S1 is the dominant root for the Gastrocnemius and Soleus, **L5** contributes to the motor supply of the posterior compartment of the leg. **3. Clinical Pearls for NEET-PG:** * **L5 Nerve Root Syndrome:** Typically presents with "Foot Drop" (weakness in dorsiflexion) and weakness in **Great Toe Extension** (EHL). * **Trendelenburg Sign:** L5 supplies the Gluteus medius and minimus (via the Superior Gluteal Nerve). An L5 lesion can lead to a positive Trendelenburg sign due to weak hip abduction. * **Sensory Loss:** L5 involvement typically causes sensory loss/paresthesia over the **lateral leg and the dorsum of the foot** (including the first web space). * **Reflexes:** Note that L5 does not have a specific deep tendon reflex (Knee jerk is L3-L4; Ankle jerk is S1).

Q: What is the cutaneous nerve supply of the region marked X?

Superficial peroneal nerve. ***Superficial peroneal nerve*** - Innervates the **dorsum of the foot** except the first web space and lateral border of the little toe. - The region marked X is located on the **dorsum of the foot** (excluding the first dorsal web space), which is the territory of the superficial peroneal nerve. *Deep peroneal nerve* - Provides **cutaneous innervation** exclusively to the **first dorsal web space** between the great toe and second toe. - Does **not supply** the broader dorsal region where X is marked. *Medial plantar nerve* - Supplies the **plantar surface** of the medial three and a half toes, not the dorsal web space. - Functions on the **sole of the foot**, not the dorsal aspect where region X is located. *Saphenous nerve* - Provides cutaneous supply to the **medial aspect of the foot** and lower leg. - Does **not innervate** the dorsum of the foot where X is marked.

Q: A serious complication of fractures of the femoral neck is avascular necrosis of the femoral head. This usually results from rupture of which artery?

Medial circumflex femoral. The blood supply to the head of the femur is derived from three main sources: the trochanteric anastomosis (retinacular arteries), the cruciate anastomosis, and the artery of the ligamentum teres. The **Medial Circumflex Femoral Artery (MCFA)** is the most significant contributor. It gives off **superior and inferior retinacular branches** that pierce the joint capsule and run along the femoral neck to reach the head. In intracapsular fractures of the femoral neck, these retinacular vessels are frequently torn or compressed, leading to ischemia and subsequent **Avascular Necrosis (AVN)**. **Analysis of Options:** * **Option A (Acetabular branch of obturator):** This artery travels within the ligamentum teres. While it supplies the head in children, it becomes insufficient to maintain viability in adults. * **Option B (Deep circumflex iliac):** This is a branch of the external iliac artery supplying the iliac crest and abdominal wall; it does not contribute to the femoral head. * **Option C (Descending branch of lateral circumflex femoral):** This branch travels inferiorly to participate in the genicular anastomosis around the knee. While the *lateral* circumflex femoral artery does contribute to the trochanteric anastomosis, the *medial* artery is the dominant source for the head. **Clinical Pearls for NEET-PG:** * **Intracapsular vs. Extracapsular:** AVN is a risk in *intracapsular* fractures (neck) but rarely in *extracapsular* fractures (intertrochanteric) because the latter occur distal to the retinacular vessel insertion. * **Garden Classification:** Used to predict the risk of AVN based on the degree of displacement in femoral neck fractures. * **Cruciate Anastomosis:** Formed by the Medial circumflex femoral, Lateral circumflex femoral (transverse branch), First perforating, and Inferior gluteal arteries.

Q: The talus bone articulates with all of the following EXCEPT:

Cuboid. The **talus** is a unique bone in the foot as it has no muscular or tendinous attachments and is covered largely by articular cartilage. It serves as the primary link between the leg and the foot. ### **Why Cuboid is the Correct Answer** The talus does **not** articulate with the cuboid. The cuboid bone is located on the lateral side of the midfoot and articulates posteriorly with the **calcaneus** (at the calcaneocuboid joint) and anteriorly with the 4th and 5th metatarsals. There is no direct contact between the talus and the cuboid. ### **Analysis of Incorrect Options** * **Tibia (Option B):** The superior surface (trochlea) of the talus articulates with the distal end of the tibia to form the **ankle joint** (talocrural joint). This is a hinge joint responsible for dorsiflexion and plantarflexion. * **Calcaneum (Option A):** The talus articulates with the calcaneus inferiorly at two points: the **subtalar joint** (posteriorly) and the **talocalcaneonavicular joint** (anteriorly/medially). These joints allow for inversion and eversion. * **Navicular (Option C):** The rounded head of the talus articulates anteriorly with the posterior surface of the navicular bone. ### **High-Yield Clinical Pearls for NEET-PG** * **Blood Supply:** The talus has a retrograde blood supply, primarily via the **Artery of the Tarsal Canal** (branch of the posterior tibial artery). Fractures of the neck of the talus carry a high risk of **Avascular Necrosis (AVN)**. * **Attachments:** It is the only bone in the foot with **no muscle attachments**. * **Joint Type:** The ankle joint is a synovial joint of the **hinge** variety. Synovial fluid provides nutrition for the articular hyaline cartilage, which lacks a direct blood supply [1]. * **Keystone:** The talus acts as the "keystone" of the **medial longitudinal arch** of the foot.

Q: A young patient presents with loss of sensation in the sole of the foot and paralysis of the medial side of the plantar muscles of the foot. Most likely nerve involvement is?

Tibial nerve. ### Explanation **1. Why Tibial Nerve is Correct:** The **Tibial nerve** (a branch of the Sciatic nerve) descends through the popliteal fossa and passes behind the medial malleolus into the foot. It terminates by dividing into the **Medial and Lateral Plantar nerves**. * **Sensory:** These branches provide cutaneous innervation to the entire **sole (plantar surface)** of the foot. * **Motor:** They supply all the intrinsic muscles of the sole. Therefore, a lesion of the Tibial nerve (specifically at or above the tarsal tunnel) results in sensory loss on the sole and paralysis of the plantar muscles. **2. Why Other Options are Incorrect:** * **Common Peroneal Nerve (CPN):** This nerve supplies the anterior and lateral compartments of the leg. Injury leads to "Foot Drop" and sensory loss on the dorsum of the foot, not the sole. * **Deep Peroneal Nerve:** A branch of the CPN, it supplies the anterior compartment muscles (dorsiflexors) and the skin of the **first web space**. It does not supply the sole. * **Superficial Peroneal Nerve:** Also a branch of the CPN, it supplies the peroneal muscles (evertors) and the skin of the majority of the **dorsum of the foot**. **3. Clinical Pearls for NEET-PG:** * **Tarsal Tunnel Syndrome:** Compression of the Tibial nerve behind the medial malleolus, leading to pain and paresthesia in the sole. * **Reflex:** The Tibial nerve mediates the **Ankle Jerk (S1, S2)**. * **Mnemonic for Sole Innervation:** The Medial Plantar nerve is analogous to the Median nerve in the hand (supplies 1st lumbrical and thenar-like muscles), while the Lateral Plantar nerve is like the Ulnar nerve. * **Injury Site:** The Tibial nerve is most commonly injured by deep lacerations in the popliteal fossa or posterior dislocations of the knee.

Q: What is the root value for the nerve to the quadratus femoris muscle?

L4, L5, S1. The **nerve to quadratus femoris** is a branch of the **sacral plexus**. It arises from the ventral rami of the **L4, L5, and S1** spinal nerves. It exits the pelvis through the greater sciatic foramen (infra-piriform compartment) and supplies two muscles: the **quadratus femoris** and the **inferior gemellus**. It also provides an articular branch to the hip joint. **Analysis of Options:** * **L4, L5, S1 (Correct):** This is the specific root value for both the nerve to quadratus femoris and the **superior gluteal nerve**. * **L1, L2, L3 (Incorrect):** These roots contribute to the iliohypogastric, ilioinguinal, and genitofemoral nerves (lumbar plexus). * **L2, L3, L4 (Incorrect):** This is the root value for the **femoral nerve** and the **obturator nerve**, which supply the anterior and medial compartments of the thigh, respectively. * **S1, S2, S3 (Incorrect):** These roots contribute to the posterior cutaneous nerve of the thigh. The nerve to obturator internus (which supplies the superior gemellus) has a root value of L5, S1, S2. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of Two":** The nerve to quadratus femoris supplies **two** muscles (Quadratus femoris + Inferior gemellus). Similarly, the nerve to obturator internus supplies **two** muscles (Obturator internus + Superior gemellus). * **Course:** It runs deep to the tendon of the obturator internus and the gemelli muscles. * **Hip Joint Innervation:** It is a key nerve involved in the Hilton’s Law application for the hip joint. * **Mnemonic:** Remember "4-5-1" for both the **S**uperior Gluteal Nerve and the Nerve to **Q**uadratus Femoris (SQ451).

Q: Which of the following arteries is NOT involved in cruciate anastomosis?

Superior gluteal artery. The **cruciate anastomosis** is a vital collateral circulatory pathway located at the level of the lesser trochanter of the femur. It ensures a continuous blood supply to the lower limb if the femoral artery is obstructed between the origin of the profunda femoris and the popliteal artery. ### **Why Option D is Correct** The **Superior Gluteal Artery** is the correct answer because it does **not** participate in the cruciate anastomosis. Instead, it is a primary component of the **trochanteric anastomosis**, which is located higher up near the greater trochanter and supplies the head of the femur. ### **Why the Other Options are Incorrect** The cruciate anastomosis is formed by the "cross-shaped" intersection of four specific arteries: * **Inferior Gluteal Artery (Option A):** Provides the **superior** limb of the anastomosis (descending branch). * **Medial Circumflex Femoral Artery (Option B):** Provides the **medial** limb (transverse branch). * **Lateral Circumflex Femoral Artery (Option C):** Provides the **lateral** limb (transverse branch). * **First Perforating Artery:** A branch of the profunda femoris that provides the **inferior** limb (ascending branch). ### **High-Yield Clinical Pearls for NEET-PG** * **Location:** The cruciate anastomosis lies at the level of the **lesser trochanter**, whereas the trochanteric anastomosis lies in the **trochanteric fossa**. * **Trochanteric Anastomosis Components:** Superior gluteal, Inferior gluteal, Medial circumflex femoral, and Lateral circumflex femoral arteries. * **Key Distinction:** The **Superior Gluteal Artery** is involved in the trochanteric anastomosis but **never** the cruciate anastomosis. * **Clinical Significance:** These anastomoses are crucial in maintaining viability of the femoral head and lower limb in cases of femoral artery ligation or atherosclerotic occlusion.

Q: Which tarsal bone is interposed between the proximal and distal rows of the foot?

Navicular. The tarsal bones are organized into two functional rows: a **proximal row** (Talus and Calcaneus) and a **distal row** (Medial, Intermediate, and Lateral Cuneiforms, plus the Cuboid). **Explanation of the Correct Answer:** The **Navicular** bone is anatomically positioned as the "keystone" between these two rows on the medial side of the foot. It articulates posteriorly with the head of the talus (proximal row) and anteriorly with the three cuneiform bones (distal row). This unique interposition makes it essential for the integrity of the **medial longitudinal arch**. **Analysis of Incorrect Options:** * **Talus & Calcaneus (Options A & B):** These constitute the **proximal row** (hindfoot). The talus sits superiorly to transmit body weight from the tibia, while the calcaneus forms the heel. * **Cuboid (Option C):** While the cuboid is sometimes described as being lateral to the navicular, it is functionally part of the **distal row**. It articulates posteriorly with the calcaneus, but unlike the navicular, it does not act as a bridge between rows; rather, it sits directly in the lateral column of the distal tarsus. **High-Yield Clinical Pearls for NEET-PG:** * **The "Boat" Bone:** Navicular is derived from the Latin *navicula* (little ship) due to its concave proximal surface. * **Tibialis Posterior Insertion:** The tuberosity of the navicular is the primary insertion site for the Tibialis Posterior muscle. An accessory navicular bone (Os Tibiale Externum) can sometimes be found here, causing medial foot pain. * **Köhler’s Disease:** This is the avascular necrosis of the navicular bone, typically seen in children. * **Chopart’s Joint:** The mid-tarsal joint (transverse tarsal joint) is formed by the talonavicular and calcancocuboid articulations.

Question 1

The involvement of the L5 Nerve Root can affect all of the following movements, except?

Accepted Answer

Adduction of the thigh

Answer

Flexion of the knee

Answer

Extension of the great toe

Answer

Plantarflexion of the foot

Question 2

What is the cutaneous nerve supply of the region marked X?

Accepted Answer

Superficial peroneal nerve

Answer

Saphenous nerve

Answer

Medial plantar nerve

Answer

Deep peroneal nerve

Question 3

A serious complication of fractures of the femoral neck is avascular necrosis of the femoral head. This usually results from rupture of which artery?

Accepted Answer

Medial circumflex femoral

Answer

Acetabular branch of obturator

Answer

Deep circumflex iliac

Answer

Descending branch of lateral circumflex femoral

Question 4

The talus bone articulates with all of the following EXCEPT:

Accepted Answer

Cuboid

Answer

Calcaneum

Answer

Tibia

Answer

Navicular

Question 5

Which nerve is most likely to be injured in a posterior dislocation of the hip joint?

Accepted Answer

Sciatic nerve

Answer

Superior gluteal nerve

Answer

Inferior gluteal nerve

Answer

Pudendal nerve

Question 6

A young patient presents with loss of sensation in the sole of the foot and paralysis of the medial side of the plantar muscles of the foot. Most likely nerve involvement is?

Accepted Answer

Tibial nerve

Answer

Common peroneal nerve

Answer

Deep peroneal nerve

Answer

Superficial peroneal nerve

Question 7

What is the root value for the nerve to the quadratus femoris muscle?

Accepted Answer

L4, L5, S1

Answer

L1, L2, L3

Answer

L2, L3, L4

Answer

S1, S2, S3

Question 8

Which of the following arteries is NOT involved in cruciate anastomosis?

Accepted Answer

Superior gluteal artery

Answer

Inferior gluteal artery

Answer

Medial circumflex femoral artery

Answer

Lateral circumflex femoral artery

Question 9

A patient presents with defective adduction of the hip joint and pain in the hip and knee joint. Which nerve is involved?

Accepted Answer

Obturator nerve

Answer

Femoral nerve

Answer

Saphenous nerve

Answer

Sciatic nerve

Question 10

Which tarsal bone is interposed between the proximal and distal rows of the foot?

Accepted Answer

Navicular

Answer

Talus

Answer

Calcaneus

Answer

Cuboid

Lower Limb — MCQs

Lower Limb — MCQs

On this page

Practice by Chapter

Want unlimited practice?