Applied Surgical Anatomy — MCQs
Trendelenburg's sign is positive in injury to which structure?
Patient with shoulder dislocation has axillary nerve injury. Which movement will be most affected?
Which nerve is commonly damaged in fracture of neck of fibula?
"Trendelenburg sign" is positive in damage of the following nerve:
An 18-year-old athlete presents with acute knee pain and hemarthrosis after pivoting. The Lachman test is positive. Which ligament is most likely injured?
A 58-year-old male with a history of hypertension and smoking presents with sudden severe back pain and hypotension. A CT scan reveals a 7 cm ruptured abdominal aortic aneurysm (AAA). What are the key factors in deciding whether to proceed with endovascular aneurysm repair (EVAR) or open surgical repair?
Which of the following statements is true regarding supracondylar fractures of the humerus?
Identify the true statement regarding the clinical examination given in the image:
The most commonly involved nerve in lunate dislocation is -
Avascular necrosis (AVN) is commonly associated with which type of femoral neck fracture?
Applied Surgical Anatomy Indian Medical PG Practice Questions and MCQs
Question 1: Trendelenburg's sign is positive in injury to which structure?
- A. Gluteus maximus
- B. Gluteus medius (Correct Answer)
- C. Quadriceps femoris
- D. Quadratus lumborum
Explanation: ***Gluteus medius*** - A positive **Trendelenburg's sign** indicates weakness or paralysis of the **gluteus medius** muscle, or problem with its innervation or hip joint. - This muscle is crucial for **abduction** and **stabilization** of the pelvis during gait; its dysfunction causes the unsupported side of the pelvis to drop. *Gluteus maximus* - The **gluteus maximus** is primarily involved in **hip extension** and external rotation, not hip abduction or pelvic stability during single-leg stance. - Weakness in this muscle would manifest more as difficulty with climbing stairs or rising from a seated position. *Quadriceps femoris* - The **quadriceps femoris** muscles are responsible for **knee extension**, essential for walking and standing. - Injury to these muscles would primarily affect the ability to **straighten the leg** and bear weight on it, not cause pelvic drop. *Quadratus lumborum* - The **quadratus lumborum** is a deep abdominal muscle involved in **lateral flexion of the trunk** and stabilization of the lumbar spine. - Dysfunction of this muscle would lead to **trunk instability** or pain, but not the specific pelvic drop seen in Trendelenburg's sign.
Question 2: Patient with shoulder dislocation has axillary nerve injury. Which movement will be most affected?
- A. Forward Flexion
- B. Internal Rotation
- C. Shoulder Abduction (Correct Answer)
- D. External Rotation
Explanation: ***Shoulder Abduction*** - The **axillary nerve** innervates the **deltoid muscle**, which is the primary muscle responsible for **shoulder abduction** beyond the initial 15 degrees. - Injury to this nerve would significantly impair the patient's ability to lift their arm away from their body. *Forward Flexion* - **Forward flexion** of the shoulder is primarily carried out by the **anterior deltoid**, **pectoralis major**, and **coracobrachialis muscles**. - While the anterior deltoid is affected, other muscles can still contribute to this movement, making it less severely impaired than abduction. *Internal Rotation* - **Internal rotation** is largely controlled by the **subscapularis**, **latissimus dorsi**, **teres major**, and **pectoralis major**. - These muscles are not innervated by the axillary nerve, so internal rotation would be largely preserved. *External Rotation* - **External rotation** is primarily performed by the **infraspinatus** and **teres minor muscles**. - These muscles are supplied by the **suprascapular nerve** and **axillary nerve** (for teres minor), respectively, but the deltoid's role is minimal, so overall external rotation would be less affected compared to abduction.
Question 3: 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 4: "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 5: An 18-year-old athlete presents with acute knee pain and hemarthrosis after pivoting. The Lachman test is positive. Which ligament is most likely injured?
- A. Posterior Cruciate Ligament
- B. Anterior Cruciate Ligament (Correct Answer)
- C. Lateral Collateral Ligament
- D. Medial Collateral Ligament
Explanation: ***Anterior Cruciate Ligament*** - The **Lachman test** is the most sensitive clinical test for diagnosing an **ACL tear**, indicating anterior tibial translation. - **Pivoting injuries** and **hemarthrosis** (blood in the joint) are classic signs of a severe ACL injury, often involving bone bruising. *Posterior Cruciate Ligament* - PCL injuries are less common and typically result from a direct blow to the **anterior tibia** while the knee is flexed or a hyperextension injury. - The primary test for PCL integrity is the **posterior drawer test**, which assesses posterior tibial translation. *Lateral Collateral Ligament* - LCL injuries usually result from a **varus stress** to the knee, often in contact sports, and can cause pain on the lateral aspect of the knee. - The **varus stress test** is used to assess LCL integrity, but it does not cause hemarthrosis as frequently as an ACL tear. *Medial Collateral Ligament* - MCL injuries are common and result from a **valgus stress** to the knee (a blow to the outside of the knee). - The **valgus stress test** assesses MCL integrity, causing pain on the medial aspect of the knee and typically not resulting in acute hemarthrosis unless other structures are also injured.
Question 6: A 58-year-old male with a history of hypertension and smoking presents with sudden severe back pain and hypotension. A CT scan reveals a 7 cm ruptured abdominal aortic aneurysm (AAA). What are the key factors in deciding whether to proceed with endovascular aneurysm repair (EVAR) or open surgical repair?
- A. Patient's hemodynamic stability, anatomy of the aneurysm, and access to EVAR equipment (Correct Answer)
- B. Patient's hemodynamic stability and anatomy of the aneurysm
- C. Access to EVAR equipment and patient's age
- D. Surgeon's experience with EVAR procedures
Explanation: ***Patient's hemodynamic stability, anatomy of the aneurysm, and access to EVAR equipment*** - **Hemodynamic stability** is crucial; unstable patients may benefit from more rapid intervention, potentially open repair, or require stabilization before EVAR. - The **anatomy of the aneurysm** (e.g., neck length, angulation, iliac artery access) dictates suitability for EVAR, as specific morphological criteria must be met for stent-graft placement. - **Access to EVAR equipment and trained personnel** is also a practical consideration for emergency intervention. *Patient's hemodynamic stability and anatomy of the aneurysm* - While **hemodynamic stability** and **aneurysm anatomy** are critical factors, access to specialized EVAR equipment and facilities is also a practical determinant of whether EVAR can even be attempted, especially in an emergent setting. - This option overlooks the logistical requirements necessary for performing an **EVAR procedure**. *Access to EVAR equipment and patient's age* - **Access to EVAR equipment** is important, but **patient's age** is generally less critical than factors like physiological status, comorbidities, and aneurysm morphology when deciding between EVAR and open repair for ruptured AAAs. - Younger patients may tolerate open surgery better, but age alone does not preclude EVAR if anatomy is suitable. *Surgeon's experience with EVAR procedures* - While **surgeon experience** is important for procedural success and outcomes, it is considered secondary to the immediate patient-centered and anatomical factors. - In emergency settings, the decision primarily hinges on the **patient's hemodynamic status**, **aneurysm anatomical suitability**, and **immediate availability of EVAR resources**, rather than being driven by surgeon preference based on experience alone. - Institutional protocols typically guide whether EVAR or open repair should be attempted based on the factors in the correct answer.
Question 7: Which of the following statements is true regarding supracondylar fractures of the humerus?
- A. Extension type most common (Correct Answer)
- B. Flexion type is less common than extension type
- C. Both types are equally common
- D. More common in adults
Explanation: **Extension type most common** - **Extension-type supracondylar fractures** account for the vast majority (about 95%) of all supracondylar humerus fractures. - This type typically results from a fall on an **outstretched hand** with the elbow in extension, forcing the distal fragment posteriorly. *More common in adults* - **Supracondylar fractures of the humerus** are predominantly observed in children, especially between 5 and 10 years of age. - They are the **most common elbow fracture in children**, making this statement incorrect. *Flexion type is less common than extension type* - While flexion-type fractures do occur, they are significantly less common, representing only about 5% of all supracondylar fractures. - This type typically results from a direct blow to the posterior aspect of the elbow, with the distal fragment displaced anteriorly. *Both types are equally common* - As established, extension-type fractures are far more prevalent than flexion-type fractures, making them not equally common. - The significant disparity in incidence confirms that this statement is incorrect.
Question 8: Identify the true statement regarding the clinical examination given in the image:
- A. Wrist is held in forced flexion for 60 sec eliciting pain (Correct Answer)
- B. Wrist is held in forced extension for 60 sec
- C. Wrist is held in forced flexion for 45 sec eliciting pain
- D. Wrist is held in forced extension for 45 sec
Explanation: ***Wrist is held in forced flexion for 60 sec eliciting pain*** - The image depicts **Phalen's test**, used to diagnose **carpal tunnel syndrome**. In this test, the patient's wrists are held in maximal sustained **flexion** for 30-60 seconds. - The reproduction of **tingling or pain** in the median nerve distribution (thumb, index, middle, and radial half of the ring finger) within this time frame indicates a positive test. *Wrist is held in forced extension for 60 sec* - Holding the wrist in **forced extension** for 60 seconds describes **reverse Phalen's test**, not the standard Phalen's test shown. - While reverse Phalen's test also assesses for **carpal tunnel syndrome**, it typically involves holding the wrists in **extension**. *Wrist is held in forced flexion for 45 sec eliciting pain* - While **flexion** is correct for Phalen's test, the standard duration is up to **60 seconds**, not specifically 45 seconds to determine a positive result. - Pain should be elicited within this timeframe, but the 45-second duration is not the most accurate statement regarding the full range of the test's timing. *Wrist is held in forced extension for 45 sec* - This option incorrectly states **forced extension** rather than flexion for Phalen's test, and the specific duration of 45 seconds is not universally cited as the definitive endpoint for a positive result. - **Forced extension** is part of the reverse Phalen's maneuver, not the test shown.
Question 9: The most commonly involved nerve in lunate dislocation is -
- A. Ulnar nerve
- B. Median nerve (Correct Answer)
- C. Posterior interosseous
- D. Anterior interosseous
Explanation: ***Median nerve*** - In a **lunate dislocation**, the lunate bone dislocates anteriorly and rotates. This displaced lunate can directly compress the **median nerve** within the carpal tunnel, which lies just anterior to it. - Compression of the median nerve leads to symptoms of **carpal tunnel syndrome**, including numbness and tingling in the thumb, index, middle, and radial half of the ring finger. *Ulnar nerve* - The **ulnar nerve** passes through Guyon's canal, which is located more medially and is generally not directly compressed by an isolated lunate dislocation. - While other wrist injuries can affect the ulnar nerve, it is not the most common nerve involved in lunate dislocation. *Posterior interosseous* - The **posterior interosseous nerve** is a branch of the radial nerve and supplies muscles in the posterior compartment of the forearm; it is located away from the carpal bones and is very rarely affected by lunate dislocation. - Injury to this nerve typically results in wrist drop or issues with finger extension. *Anterior interosseous* - The **anterior interosseous nerve** is a branch of the median nerve that supplies deep flexor muscles in the forearm; it also lies away from the direct path of a dislocated lunate. - Injury to this nerve leads to an inability to make the "ok" sign due to paralysis of the flexor pollicis longus and flexor digitorum profundus to the index finger.
Question 10: Avascular necrosis (AVN) is commonly associated with which type of femoral neck fracture?
- A. Transcervical
- B. Basal
- C. Subcapital (Correct Answer)
- D. Intertrochanteric
Explanation: ***Subcapital*** - Subcapital fractures occur at the anatomical **neck of the femur**, just below the femoral head, and often disrupt the **blood supply** to the femoral head due to injury to the lateral epiphyseal arteries. - The high rate of **vascular disruption** in these fractures significantly increases the risk of avascular necrosis (AVN) a condition where bone tissue dies due to lack of blood supply. *Transcervical* - Transcervical fractures are located through the **middle part of the femoral neck**, between subcapital and basal fractures, and also carry a risk of AVN. - However, the risk of AVN is generally considered **lower than subcapital fractures** but higher than basal fractures, due to less consistent disruption of the retinacular vessels. *Basal* - Basal fractures occur at the **base of the femoral neck**, near the intertrochanteric line, and typically have a **better prognosis** regarding AVN. - The principal blood supply to the femoral head is usually **less compromised** in basal fractures compared to subcapital or transcervical fractures, as the fracture line is more distal to the weight-bearing femoral head. *Intertrochanteric* - Intertrochanteric fractures occur **outside the hip joint capsule**, in the region between the greater and lesser trochanters, and are considered **extracapsular**. - Due to their location being well away from the **femoral head's vascular supply**, these fractures have a very low risk of avascular necrosis and primarily raise concerns about stability and healing.
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