Applied Anatomy and Clinical Correlations — MCQs
AVN of femoral head is most common in-
Claudication due to femoropopliteal incompetence is primarily seen in
Foot drop occurs due to the involvement of:
Which nerve is commonly damaged in fracture of neck of fibula?
Lurching Gait is due to paralysis of which of the following?
Which of the following findings appear late in compartment syndrome?
"Trendelenburg sign" is positive in damage of the following nerve:
What is the consequence of tibial nerve injury/palsy?
Trendelenberg test is negative in
A patient fell off a bicycle and is now experiencing pain around the hip, shortening of the limb, and the hip is positioned in flexion, adduction, and internal rotation (IR). What is the most likely diagnosis?
Applied Anatomy and Clinical Correlations Indian Medical PG Practice Questions and MCQs
Question 1: AVN of femoral head is most common in-
- A. Intracapsular fracture neck of femur (Correct Answer)
- B. Extracapsular fracture neck of femur
- C. Fracture shaft humerus
- D. Subtrochanteric fracture
Explanation: ***Intracapsular fracture neck of femur*** - **Intracapsular fractures** disrupt the blood supply to the femoral head, particularly the **retinacular arteries**, leading to **avascular necrosis (AVN)**. - The femoral head receives most of its blood supply from within the capsule, making it highly susceptible to **ischemia** when these vessels are damaged. *Extracapsular fracture neck of femur* - These fractures occur **outside the joint capsule**, preserving the critical retinacular arterial blood supply to the femoral head. - While they can lead to other complications, **avascular necrosis** is rare because the blood flow to the femoral head is largely uninterrupted. *Fracture shaft humerus* - This type of fracture involves the **upper arm bone** and has no direct anatomical or vascular connection to the femoral head. - It does not interfere with the blood supply to the femoral head, and thus, **AVN of the femoral head** is not a complication. *Subtrochanteric fracture* - **Subtrochanteric fractures** occur in the proximal femur, but **below the trochanters** and outside the joint capsule. - Like extracapsular fractures, they typically do not compromise the **retinacular arteries** supplying the femoral head, making AVN an unlikely complication.
Question 2: Claudication due to femoropopliteal incompetence is primarily seen in
- A. Thigh
- B. Calf (Correct Answer)
- C. Buttocks
- D. Feet
Explanation: ***Calf*** - **Femoropopliteal incompetence** refers to insufficiency in the superficial femoral and popliteal arteries. Blockage in these arteries typically results in **claudication** symptoms downstream from the obstruction. - The **calf muscles** receive their blood supply via these arteries and are therefore the primary site of pain due to inadequate blood flow during exertion, manifesting as claudication. *Thigh* - Claudication in the **thigh** is usually associated with more proximal arterial obstructions in the **aortoiliac system** or common femoral artery. - While thigh muscles are located upstream from the calf, pain would indicate a blockage higher up than the femoropopliteal segment. *Buttocks* - **Buttock claudication** points to very proximal arterial disease, specifically involving the **internal iliac arteries** or the distal aorta (**Leriche syndrome**). - This is even further upstream than the femoropopliteal arteries and would involve more significant and widespread circulatory compromise. *Feet* - While the **feet** can experience pain due to arterial insufficiency, particularly with severe disease or at rest, isolated foot claudication is less common. - **Claudication** specifically points to muscle ischemia during activity, and the robust musculature of the calf makes it the primary site when femoropopliteal arteries are involved.
Question 3: Foot drop occurs due to the involvement of:
- A. Obturator nerve
- B. Sciatic nerve
- C. Direct injury to the dorsiflexors
- D. Common peroneal nerve palsy (Correct Answer)
Explanation: ***Common peroneal nerve palsy*** - The **common peroneal nerve** (also known as the common fibular nerve) innervates the muscles responsible for **dorsiflexion** and eversion of the foot (tibialis anterior, extensor hallucis longus, extensor digitorum longus, peroneus longus and brevis). - Damage to this nerve leads to weakness or paralysis of these muscles, resulting in **foot drop**, which is the most common neurological cause. - The nerve is vulnerable at the **neck of the fibula** where it is superficial and can be compressed or injured. *Sciatic nerve* - The **sciatic nerve** divides into the tibial and common peroneal nerves. - Proximal sciatic nerve injury can cause foot drop, but it would also cause additional deficits including hamstring weakness, loss of ankle plantarflexion, and sensory loss over a wider distribution. - Isolated foot drop typically indicates **common peroneal nerve** injury, not sciatic nerve injury. *Direct injury to the dorsiflexors* - Direct trauma to the **dorsiflexor muscles** (tibialis anterior, extensor hallucis longus, extensor digitorum longus) can mechanically impair dorsiflexion. - However, the term "foot drop" typically refers to **neurological causes** rather than direct muscle injury, making common peroneal nerve palsy the more specific answer. *Obturator nerve* - The **obturator nerve** innervates the **adductor muscles of the thigh** (adductor longus, adductor brevis, adductor magnus, gracilis). - It does not innervate any muscles responsible for dorsiflexion of the foot and therefore **cannot cause foot drop**.
Question 4: Which nerve is commonly damaged in fracture of neck of fibula?
- A. Tibial
- B. Common peroneal (Correct Answer)
- C. Superficial peroneal
- D. Deep peroneal
Explanation: ***Common peroneal*** - The **common peroneal nerve** (also known as the **common fibular nerve**) wraps superficially around the **neck of the fibula**, making it highly vulnerable to injury in fractures of this region. - Damage to this nerve typically results in **foot drop** and sensory loss over the dorsum of the foot and lateral leg, due to impaired dorsiflexion and eversion. *Tibial* - The **tibial nerve** lies in the posterior compartment of the leg and is generally well-protected, making it less susceptible to injury from a fibular neck fracture. - Injury to the tibial nerve would primarily affect plantarflexion of the foot and sensation to the sole. *Superficial peroneal* - The **superficial peroneal nerve** is a branch of the common peroneal nerve that descends along the lateral compartment of the leg. - While it originates from the common peroneal, a direct fracture of the fibular neck is more likely to injure the main common peroneal trunk rather than just this specific branch, leading to a broader deficit. *Deep peroneal* - The **deep peroneal nerve** is another branch of the common peroneal nerve that runs through the anterior compartment of the leg. - Similar to the superficial peroneal nerve, a fracture at the fibular neck is more likely to affect the main **common peroneal nerve** directly.
Question 5: Lurching Gait is due to paralysis of which of the following?
- A. Gluteus medius (Correct Answer)
- B. Adductor magnus
- C. Hamstrings
- D. Quadriceps femoris
Explanation: ***Gluteus medius*** * Paralysis of the **gluteus medius** leads to a **Trendelenburg gait** or **lurching gait**, where the pelvis drops on the unsupported side during walking. * This muscle is crucial for **stabilizing the pelvis** during the single-limb support phase of gait. *Adductor Magnus* * Paralysis of the adductor magnus would primarily affect **thigh adduction** and extension, not directly causing a lurching gait. * Problems with this muscle might impact the ability to bring the legs together or stabilize the leg during certain movements. *Hamstrings* * The hamstrings are responsible for **knee flexion** and **hip extension**. * Paralysis would result in difficulty bending the knee and limited hip extension, potentially leading to a stiff-knee gait, but not typically a lurching gait. *Quadriceps femoris* * The quadriceps femoris is essential for **knee extension** and is critical for activities like standing, walking, and climbing stairs. * Paralysis would cause the knee to buckle, leading to a **knee-hyperflexion gait** or difficulty with weight-bearing on that leg.
Question 6: Which of the following findings appear late in compartment syndrome?
- A. Paralysis
- B. Pain on passive stretch
- C. Pulselessness (Correct Answer)
- D. Pallor
Explanation: ***Pulselessness*** - **Pulselessness** is a very late and ominous sign in compartment syndrome, indicating severe arterial compromise that has progressed beyond simple venous and lymphatic outflow obstruction. - Its presence suggests **irreversible tissue damage** has likely already occurred due to prolonged ischemia. *Paralysis* - **Paralysis** is a late sign, indicating significant nerve ischemia and damage due to sustained pressure within the compartment. - While it's a serious finding, it typically appears before pulselessness, as nerves are sensitive to ischemia but arteries are more resistant to complete occlusion until very high pressures are reached. *Pain on passive stretch* - **Pain on passive stretch** is considered one of the earliest and most reliable clinical signs of early compartment syndrome. - It results from the stretching of ischemic muscle fibers within the confined compartment. *Pallor* - **Pallor** (skin paleness) is also a relatively late sign, occurring when capillary perfusion is significantly reduced due to rising intracompartmental pressure. - It usually manifests when the pressure is high enough to restrict blood flow but often precedes the complete absence of pulses.
Question 7: "Trendelenburg sign" is positive in damage of the following nerve:
- A. Inferior gluteal nerve
- B. Pudendal nerve
- C. Superior gluteal nerve (Correct Answer)
- D. Posterior tibial nerve
Explanation: ***Superior gluteal nerve*** - Damage to the superior gluteal nerve paralyzes the **gluteus medius** and **minimus** muscles, which are crucial for stabilizing the pelvis during gait. - A positive **Trendelenburg sign** is observed when the unsupported side of the pelvis drops during walking, due to the inability of the hip abductor muscles (innervated by the superior gluteal nerve) to contract effectively. *Inferior gluteal nerve* - The inferior gluteal nerve primarily innervates the **gluteus maximus**, which is responsible for hip extension and external rotation. - Damage to this nerve would primarily affect the ability to climb stairs or stand up from a seated position, but not typically cause a positive Trendelenburg sign. *Pudendal nerve* - The pudendal nerve primarily innervates the **perineum**, external anal sphincter, and external urethral sphincter. - Damage to this nerve causes issues with **urinary** and **fecal incontinence**, or sexual dysfunction, and is not associated with hip stability or the Trendelenburg sign. *Posterior tibial nerve* - The posterior tibial nerve innervates muscles in the posterior compartment of the leg, including the **gastrocnemius**, **soleus**, and muscles in the foot. - Damage to this nerve would affect **plantar flexion** of the foot and inversion, leading to a "foot drop" or gait abnormalities, but not the Trendelenburg sign.
Question 8: What is the consequence of tibial nerve injury/palsy?
- A. Loss of plantar flexion (Correct Answer)
- B. Dorsiflexion of foot at ankle joint
- C. Loss of sensation of dorsum of foot
- D. Paralysis of muscles of anterior compartment of leg
Explanation: **Loss of plantar flexion** - The **tibial nerve** innervates the muscles of the **posterior compartment of the leg**, which are primarily responsible for **plantar flexion** of the foot. - Injury to this nerve directly impairs the function of muscles like the gastrocnemius, soleus, and tibialis posterior, leading to a significant loss of the ability to point the foot downwards. *Dorsiflexion of foot at ankle joint* - **Dorsiflexion** is primarily mediated by muscles in the **anterior compartment of the leg**, such as the tibialis anterior, which are innervated by the **deep fibular nerve**. - Tibial nerve injury would not directly affect these muscles or their function; rather, it leads to issues with the opposing action. *Loss of sensation of dorsum of foot* - Sensation to the **dorsum of the foot** is primarily supplied by the **superficial fibular nerve** (for most of the dorsum) and the **deep fibular nerve** (for the first web space). - While the tibial nerve provides sensation to the sole of the foot, it does not typically innervate the dorsum. *Paralysis of muscles of anterior compartment of leg* - The muscles of the **anterior compartment of the leg** (e.g., tibialis anterior, extensor digitorum longus, extensor hallucis longus) are innervated by the **deep fibular nerve**. - A tibial nerve injury would paralyze muscles in the posterior compartment, not the anterior compartment.
Question 9: Trendelenberg test is negative in
- A. Polio myelitis
- B. Inferior Gluteal nerve
- C. Normal hip function (Correct Answer)
- D. Superior Gluteal nerve
Explanation: ***Normal hip function*** - A **negative Trendelenburg test** indicates that the hip abductor muscles (primarily the **gluteus medius and minimus**) are functioning correctly and can maintain pelvic stability when standing on one leg. - This suggests the absence of **weakness** or **dysfunction** in the hip abductors or their innervation. *Polio myelitis* - **Poliomyelitis** can cause **paralysis** and **weakness** of various muscles, including the hip abductors, leading to a **positive Trendelenburg test**. - The disease damages **motor neurons** in the spinal cord, impairing muscle function. *Inferior Gluteal nerve* - The **inferior gluteal nerve** primarily innervates the **gluteus maximus**, which is responsible for hip extension, not hip abduction. - Weakness due to inferior gluteal nerve damage would manifest as difficulty with activities like **climbing stairs** or **rising from a chair**, but typically would not cause a positive Trendelenburg test. *Superior Gluteal nerve* - The **superior gluteal nerve** innervates the **gluteus medius and minimus**, which are the primary hip abductors. - Damage to this nerve or weakness of these muscles would result in a **positive Trendelenburg test**, where the contralateral pelvis drops when standing on the affected leg.
Question 10: A patient fell off a bicycle and is now experiencing pain around the hip, shortening of the limb, and the hip is positioned in flexion, adduction, and internal rotation (IR). What is the most likely diagnosis?
- A. Intertrochanteric fracture (IT fracture)
- B. Posterior dislocation (Correct Answer)
- C. Transcervical fracture
- D. Anterior dislocation
Explanation: ***Posterior dislocation*** - The classic presentation of a **posterior hip dislocation** following trauma is a limb that is shortened, and held in **flexion, adduction, and internal rotation**. - This is the most common type of hip dislocation and often results from high-energy trauma, such as a bicycle fall. *Intertrochanteric fracture (IT fracture)* - While IT fractures also cause **pain and limb shortening**, the affected limb is typically held in **external rotation**, not internal rotation. - These fractures involve the region between the greater and lesser trochanters and are more common in elderly individuals after a fall. *Transcervical fracture* - A transcervical fracture (femoral neck fracture) also results in **pain** and **shortening** of the limb, but the limb's characteristic position is one of **external rotation**, similar to an IT fracture. - This type of fracture is typically associated with older patients with osteoporosis. *Anterior dislocation* - An **anterior hip dislocation** would present with the limb in **flexion, abduction, and external rotation**, which is contrary to the clinical presentation described (adduction and internal rotation). - This is a much rarer type of hip dislocation compared to posterior dislocation.
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