Lower Limb Practice Questions

Q: Which nerve supplies the muscle shown in the illustration?

Deep peroneal nerve. ***Deep peroneal nerve*** - Supplies all muscles in the **anterior compartment** of the leg including **tibialis anterior**, **extensor digitorum longus**, **extensor hallucis longus**, and **peroneus tertius**. - Also innervates **extensor digitorum brevis** in the foot and provides sensation to the **first web space** between the great and second toes. *Superficial peroneal nerve* - Supplies muscles of the **lateral compartment** including **peroneus longus** and **peroneus brevis**, not anterior compartment muscles. - Provides sensory innervation to most of the **dorsum of the foot** except the first web space. *Tibial nerve* - Innervates muscles of the **posterior compartment** of the leg including **gastrocnemius**, **soleus**, and **tibialis posterior**. - Also supplies intrinsic muscles of the foot via **medial and lateral plantar nerves**. *Sciatic nerve* - The **parent nerve** that divides into **tibial** and **common peroneal** (fibular) nerves at the popliteal fossa. - Primarily supplies muscles of the **posterior thigh** before its division, not individual compartments of the leg.

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?

Deep peroneal nerve. ***Deep peroneal nerve*** - Provides **cutaneous innervation** exclusively to the **first dorsal web space** between the great toe and second toe. - This is a **classic anatomical landmark** frequently tested in Indian PG exams as a one-liner fact. *Superficial peroneal nerve* - Innervates the **dorsum of the foot** except the first web space and lateral border of the little toe. - Does **not supply** the specific region between the great toe and second toe. *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 first dorsal web space between the toes.

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: Which of the following is true about attachments at the ischial tuberosity?

Origin of semimembranosus from the superolateral area. The **ischial tuberosity** is a critical high-yield landmark in lower limb anatomy, serving as the primary origin for the "hamstring" muscles. To master this, the tuberosity is divided into upper and lower functional areas by a transverse ridge. ### 1. Analysis of the Correct Option The **upper (superior) area** is further divided by an oblique ridge into two parts: * **Superolateral area:** This gives origin to the **semimembranosus** muscle. * **Inferomedial area:** This provides a common origin for the **long head of biceps femoris** and the **semitendinosus**. Therefore, **Option B** is correct as the semimembranosus specifically arises from the superolateral aspect of the upper part. ### 2. Analysis of Incorrect Options * **Options A & C:** Both the **semitendinosus** and the **long head of biceps femoris** originate from the **inferomedial** part of the upper area, not the superolateral area. * **Option D:** The **adductor magnus (ischiocondylar/hamstring part)** originates from the **lateral part of the lower area** of the ischial tuberosity. ### 3. NEET-PG High-Yield Clinical Pearls * **The "True" Hamstrings:** To be a true hamstring, a muscle must originate from the ischial tuberosity, be supplied by the tibial nerve, and cross both the hip and knee joints. (Note: The short head of biceps is *not* a true hamstring). * **Avulsion Fractures:** In athletic adolescents, forceful contraction of the hamstrings can lead to an avulsion fracture of the ischial tuberosity. * **Weaver’s Bottom:** Inflammation of the ischial bursa (located between the gluteus maximus and the tuberosity) is known as ischial bursitis, often caused by prolonged sitting on hard surfaces. * **Nerve Relation:** The **sciatic nerve** lies lateral to the ischial tuberosity as it descends into the thigh.

Q: The ischial tuberosity provides attachment to which muscle?

Adductor magnus. **Explanation:** The **ischial tuberosity** is a large, bony swelling on the posterior part of the superior ramus of the ischium. It serves as a major site for muscle attachments, specifically the "hamstring" group and the adductor magnus. **Why Adductor Magnus is correct:** The Adductor Magnus is a hybrid muscle consisting of two parts. The **Ischial (Hamstring) part** originates directly from the inferolateral part of the ischial tuberosity. It is often tested in NEET-PG because it shares the same origin and nerve supply (tibial part of the sciatic nerve) as the true hamstrings. **Analysis of Incorrect Options:** * **Obturator internus:** It originates from the internal surface of the obturator membrane and the surrounding bony margins of the obturator foramen, not the tuberosity. Its tendon passes through the lesser sciatic notch. * **Quadratus femoris:** It originates from the **lateral border** of the ischial tuberosity (just above the hamstring origin) and inserts into the quadrate tubercle of the femur. While close, it is distinct from the main tuberosity surface. * **Gluteus maximus:** It originates from the gluteal surface of the ilium, sacrum, and coccyx. It does not originate from the ischial tuberosity; rather, it **covers** the tuberosity when the hip is extended. **High-Yield Clinical Pearls for NEET-PG:** * **Hamstring Origin:** The ischial tuberosity is the common origin for Semitendinosus, Semimembranosus, and the Long head of Biceps Femoris. * **Weaver’s Bottom:** Inflammation of the ischial bursa (located between the gluteus maximus and the ischial tuberosity) is known as Ischial Bursitis. * **Pudendal Nerve:** The pudendal nerve and internal pudendal vessels pass medial to the ischial tuberosity as they enter the pudendal (Alcock’s) canal.

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.

Question 1

Which nerve supplies the muscle shown in the illustration?

Accepted Answer

Deep peroneal nerve

Answer

Superficial peroneal nerve

Answer

Tibial nerve

Answer

Sciatic nerve

Question 2

What is true regarding the semitendinosus muscle?

Accepted Answer

Proximal and distal parts are thin, with a middle fleshy part

Answer

Supplied by the common peroneal part of the sciatic nerve

Answer

Proximal part is fleshy and distal part is thin

Answer

Distal part is fleshy and proximal part is thin

Question 3

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 4

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

Accepted Answer

Deep peroneal nerve

Answer

Superficial peroneal nerve

Answer

Medial plantar nerve

Answer

Saphenous nerve

Question 5

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 6

The talus bone articulates with all of the following EXCEPT:

Accepted Answer

Cuboid

Answer

Calcaneum

Answer

Tibia

Answer

Navicular

Question 7

Which of the following is true about attachments at the ischial tuberosity?

Accepted Answer

Origin of semimembranosus from the superolateral area

Answer

Origin of semitendinosus from the superolateral area

Answer

Origin of the long head of biceps from the superolateral area

Answer

Origin of the adductor magnus from the superolateral area

Question 8

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 9

The ischial tuberosity provides attachment to which muscle?

Accepted Answer

Adductor magnus

Answer

Obturator internus

Answer

Quadratus femoris

Answer

Gluteus maximus

Question 10

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

Lower Limb — MCQs

Lower Limb — MCQs

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