Lower Limb Practice Questions

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: The blood supply to the femoral head is mostly by which artery?

Medial circumflex femoral artery. The blood supply to the femoral head is a high-yield topic in NEET-PG, as it explains the risk of avascular necrosis (AVN) following femoral neck fractures. ### **Explanation** The **Medial Circumflex Femoral Artery (MCFA)** is the primary source of blood to the femoral head. It gives off **retinacular arteries** (mainly the posterosuperior and posteroinferior groups) that pierce the joint capsule and run along the neck to reach the head. These vessels provide the vast majority of the blood supply required for the viability of the femoral head in adults. ### **Why other options are incorrect:** * **Lateral Circumflex Femoral Artery (LCFA):** While it contributes to the extracapsular arterial anastomosis around the hip, its branches (mainly the ascending branch) provide significantly less blood to the head compared to the MCFA. * **Artery of Ligamentum Teres:** This is a branch of the **Obturator artery**. In adults, it is often rudimentary and supplies only a small area around the fovea capitis. It is insufficient to maintain the viability of the head if the retinacular vessels are damaged. * **Obturator Artery:** It gives rise to the artery of the ligamentum teres but does not provide direct significant perfusion to the femoral head. ### **Clinical Pearls for NEET-PG:** 1. **Avascular Necrosis (AVN):** Intracapsular fractures of the femoral neck frequently tear the retinacular branches of the **MCFA**, leading to AVN. 2. **Cruciate Anastomosis:** The MCFA and LCFA participate in the cruciate anastomosis of the thigh, connecting the internal iliac and profunda femoris systems. 3. **Pediatric Variation:** In children, before the epiphyseal plate closes, the artery of the ligamentum teres plays a more significant role in supplying the femoral head.

Q: The neck of a femoral hernia is located at which anatomical landmark?

Below and lateral to the pubic tubercle. ### Explanation The anatomical location of the neck of a femoral hernia is a high-yield concept for distinguishing it from an inguinal hernia. [1] **Why Option C is Correct:** A femoral hernia occurs when abdominal contents protrude through the **femoral ring** into the femoral canal. [1] The femoral canal is located in the most medial compartment of the femoral sheath. Anatomically, the femoral ring (the neck of the hernia) lies **below and lateral to the pubic tubercle**. This relationship is the primary clinical landmark used to differentiate it from an inguinal hernia. [1] **Analysis of Incorrect Options:** * **Option A (Saphenous opening):** This is where the femoral hernia becomes superficial after passing through the femoral canal. While the hernia *presents* here, the "neck" is located deeper at the femoral ring. * **Option B (Above and medial to the pubic tubercle):** This describes the neck of an **Inguinal Hernia**. Remembering this distinction is crucial for physical examination. [1] * **Option D (Mid-inguinal point):** This is the landmark for the femoral artery (halfway between the ASIS and pubic symphysis). The femoral canal is medial to the femoral vein, making it much more medial than this point. **NEET-PG High-Yield Pearls:** 1. **Boundaries of the Femoral Ring:** Anteriorly (Inguinal ligament), Posteriorly (Pectineal ligament/Cooper’s ligament), Medially (Lacunar ligament), and Laterally (Femoral vein). 2. **Strangulation:** Femoral hernias have the highest risk of strangulation because the femoral ring is narrow and rigid (especially the sharp edge of the lacunar ligament). [1] 3. **Epidemiology:** More common in **females** due to a wider pelvis and larger femoral canal. 4. **Cloquet’s Node:** A lymph node found within the femoral canal that may be enlarged and mimic a femoral hernia.

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.

Q: Which neurovascular structure passes through both the greater and lesser sciatic foramen?

Pudendal nerve. The pelvic outlet is divided by the sacrospinous and sacrotuberous ligaments into the **greater sciatic foramen (GSF)** and **lesser sciatic foramen (LSF)**. The GSF serves as the exit from the pelvis to the gluteal region, while the LSF serves as the entrance from the gluteal region to the perineum. ### Why the Pudendal Nerve is Correct The **Pudendal nerve** (S2-S4) and the **Internal pudendal vessels** follow a unique "hook-like" course. They exit the pelvis through the GSF (inferior to the piriformis muscle), cross the ischial spine, and immediately re-enter the pelvis through the LSF to reach the perineum via Alcock’s canal. *Note: The Nerve to the Obturator Internus also follows this specific path.* ### Why Other Options are Incorrect * **Sciatic Nerve:** The largest nerve in the body; it exits the pelvis through the GSF (inferior to piriformis) and continues down the posterior thigh. It **does not** re-enter the LSF. * **Superior Gluteal Nerve:** Exits the GSF **above** the piriformis muscle to supply the gluteus medius, minimus, and tensor fasciae latae. * **Inferior Gluteal Nerve:** Exits the GSF **below** the piriformis to supply the gluteus maximus. ### NEET-PG High-Yield Pearls * **The "PIN" Mnemonic:** Structures passing through both GSF and LSF are the **P**udendal nerve, **I**nternal pudendal vessels, and **N**erve to obturator internus. * **Piriformis Muscle:** Known as the "Key to the Gluteal Region" because it divides the GSF into supra-piriform and infra-piriform compartments. * **Clinical Correlation:** The pudendal nerve is targeted for a **Pudendal Nerve Block** during vaginal delivery; the landmark used is the **ischial spine**, where the nerve passes between the two foramina.

Question 1

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 2

The talus bone articulates with all of the following EXCEPT:

Accepted Answer

Cuboid

Answer

Calcaneum

Answer

Tibia

Answer

Navicular

Question 3

The blood supply to the femoral head is mostly by which artery?

Accepted Answer

Medial circumflex femoral artery

Answer

Lateral circumflex femoral artery

Answer

Artery of ligamentum teres

Answer

Obturator artery

Question 4

The neck of a femoral hernia is located at which anatomical landmark?

Accepted Answer

Below and lateral to the pubic tubercle

Answer

Saphenous opening

Answer

Above and medial to the pubic tubercle

Answer

Mid inguinal point

Question 5

Venous flow in the lower limb veins in the standing position depends upon all except:

Accepted Answer

Arterial blood pressure

Answer

Presence of deep fascial planes

Answer

Compression of calf muscles

Answer

Presence of perforators

Question 6

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 7

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 8

The ischial tuberosity provides attachment to which muscle?

Accepted Answer

Adductor magnus

Answer

Obturator internus

Answer

Quadratus femoris

Answer

Gluteus maximus

Question 9

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 10

Which neurovascular structure passes through both the greater and lesser sciatic foramen?

Accepted Answer

Pudendal nerve

Answer

Sciatic nerve

Answer

Superior gluteal nerve

Answer

Inferior gluteal nerve

Lower Limb — MCQs

Lower Limb — MCQs

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