Trauma Practice Questions

Q: Which nerve is most commonly damaged in posterior dislocation of the hip?

Sciatic nerve. **Explanation:** **1. Why Sciatic Nerve is Correct:** The **sciatic nerve** is the most commonly injured nerve in posterior hip dislocations (occurring in approximately 10–20% of cases). This is due to its anatomical proximity; the nerve exits the pelvis through the greater sciatic foramen and descends directly **posterior** to the acetabulum and the femoral head. When the femoral head is forced posteriorly out of the acetabulum (typically via a "dashboard injury"), it directly compresses or stretches the sciatic nerve. Specifically, the **peroneal division** of the sciatic nerve is more frequently affected than the tibial division. **2. Why Other Options are Incorrect:** * **Femoral Nerve:** Located **anterior** to the hip joint. It is more likely to be injured in *anterior* hip dislocations, which are much less common than posterior ones. * **Obturator Nerve:** Located **medially** and passes through the obturator canal. It is rarely injured in hip trauma but may be affected in medial wall acetabular fractures or anterior-inferior dislocations. * **Superior Gluteal Nerve:** Runs superior to the piriformis muscle. While it can be injured during surgical approaches (like the Hardinge approach), it is not typically damaged by the displacement of the femoral head in a posterior dislocation. **3. NEET-PG High-Yield Pearls:** * **Mechanism of Injury:** Most common is a "Dashboard Injury" (force applied to a flexed knee with the hip flexed and adducted). * **Clinical Presentation:** The limb is held in **Flexion, Adduction, and Internal Rotation** (F-AD-IR). * **Complications:** Avascular Necrosis (AVN) of the femoral head is the most serious late complication; Sciatic nerve palsy is the most common early neurological complication. * **Management:** Emergency closed reduction (e.g., Allis maneuver) should be performed within 6 hours to minimize AVN risk.

Q: Mc.Murray osteotomy is used in which of the following conditions?

Fracture neck of femur. **McMurray Osteotomy** is a high-yield topic in orthopaedics, specifically regarding the management of **ununited fractures of the neck of the femur**. ### **Explanation of the Correct Answer** McMurray osteotomy is a **displacement proximal femoral osteotomy** performed at the level of the lesser trochanter. The primary goal is to convert **shearing forces** into **compressive forces** at the fracture site. By displacing the distal femoral shaft medially, the weight-bearing axis is shifted directly under the fracture line. This promotes healing in cases of non-union or delayed union of femoral neck fractures, especially in younger patients where head preservation is preferred over replacement. ### **Analysis of Incorrect Options** * **A. CTEV:** Surgical management for clubfoot involves soft tissue releases (like Turco’s procedure) or bony procedures like **Dwyer’s osteotomy** (calcaneal) or **Evans procedure**, but not McMurray’s. * **C. Supracondylar humerus fracture:** Malunion here (Cubitus varus) is typically treated with a **French osteotomy** (lateral closed wedge osteotomy). * **D. Condylar fracture of femur:** These are intra-articular fractures managed with ORIF (Open Reduction Internal Fixation) using distal femoral plates or screws, not proximal displacement osteotomies. ### **Clinical Pearls for NEET-PG** * **Type of Osteotomy:** It is a "Medial Displacement Osteotomy." * **Pauwels’ Classification:** It is particularly relevant for Pauwels Type III fractures (vertical fracture line >70°), which are highly unstable due to shear stress. * **Other Femoral Osteotomies:** * **Schanz Osteotomy:** Used for neglected CCH (Congenital Dislocation of Hip). * **Girdlestone Procedure:** A salvage excision arthroplasty for the hip. * **Chiari Osteotomy:** A pelvic osteotomy to increase acetabular coverage.

Q: An elderly female presents with a history of a fall and inability to move. Following the fall, her leg was noted to be in an externally rotated position. There is tenderness in Scarpa's triangle, and limb movement is significantly limited due to pain. Initial X-ray ruled out hip fracture. What is the next diagnostic step?

MRI. **Explanation:** The clinical presentation of an elderly patient with a fall, external rotation of the limb, and tenderness in **Scarpa’s triangle** is highly suggestive of a **hip fracture** (specifically a femoral neck fracture). However, in elderly patients with osteoporosis, fractures can be **occult** (not visible on initial radiographs). 1. **Why MRI is Correct:** MRI is the **gold standard** for diagnosing occult hip fractures. It has nearly 100% sensitivity and can detect bone marrow edema and fracture lines within 24 hours of injury. When clinical suspicion is high but X-rays are negative, MRI is the immediate next step to prevent fracture displacement or avascular necrosis (AVN). 2. **Why other options are incorrect:** * **Repeat X-ray after one week:** While callus formation might eventually show a fracture, delaying diagnosis in an elderly patient leads to prolonged immobilization, increasing the risk of DVT, pneumonia, and pressure sores. * **Joint aspiration:** This is primarily used to diagnose septic arthritis or crystal arthropathy, not trauma-related fractures. * **Analgesics and manipulation:** Attempting manipulation without a diagnosis is dangerous and may displace an undisplaced fracture, compromising the blood supply (medial circumflex femoral artery). **Clinical Pearls for NEET-PG:** * **Occult Fracture:** A fracture that is clinically suspected but not visible on initial X-rays. * **Imaging Hierarchy:** If MRI is unavailable or contraindicated (e.g., pacemaker), a **CT scan** or **Bone Scan** (after 48-72 hours) are alternatives. * **Scarpa’s Triangle Tenderness:** A classic sign of intracapsular hip fractures. * **Positioning:** Femoral neck fractures typically present with **shortening and external rotation**.

Q: What is the characteristic position of the arm in an anterior shoulder dislocation?

By the side. In an anterior shoulder dislocation—the most common type of shoulder dislocation (95%)—the humeral head is displaced anteriorly and inferiorly out of the glenoid fossa. **Explanation of the Correct Answer:** The characteristic clinical presentation of a patient with an acute anterior shoulder dislocation is the arm held **by the side** (slightly abducted) and supported by the opposite hand. While the initial mechanism of injury often involves abduction and external rotation, once the dislocation is established, the patient typically presents with the arm fixed in **slight abduction and external rotation**, but functionally held close to the body (by the side) to minimize pain and muscle spasms. **Analysis of Incorrect Options:** * **In Abduction:** While the arm is slightly abducted (the "Hamilton Ruler Test" is positive because the arm cannot touch the side), it is not held in significant or overhead abduction. * **In Adduction:** This is incorrect because the displaced humeral head prevents the arm from being fully adducted to the side of the chest (Dugas Test). * **In External Rotation:** Although the arm is externally rotated, the most defining "positional" description in clinical exams is the arm being held by the side/slightly abducted. **NEET-PG High-Yield Clinical Pearls:** 1. **Flattening of the Shoulder:** Loss of the normal rounded contour of the deltoid (Square shoulder/Epaulette sign). 2. **Dugas Test:** The patient is unable to touch the opposite shoulder with the hand of the affected side. 3. **Hamilton Ruler Test:** A straight edge can touch both the acromion and the lateral epicondyle simultaneously. 4. **Associated Nerve Injury:** The **Axillary nerve** is the most commonly injured nerve (check for "regimental badge" anesthesia). 5. **Common Lesions:** Bankart lesion (labral tear) and Hill-Sachs lesion (compression fracture of the posterolateral humeral head).

Q: Which statement is not true regarding the Langenbeck-Kocher operation?

Superior exposure is very well achieved.. The **Kocher-Langenbeck (K-L) approach** is the standard posterior surgical approach to the acetabulum. Understanding its anatomical limitations is crucial for NEET-PG. ### **Explanation of the Correct Option** **Option C is the correct answer (the false statement)** because the K-L approach provides **limited superior exposure**. While it offers excellent access to the posterior column and posterior wall, it does not allow for adequate visualization of the superior aspect of the acetabulum (the "dome" or weight-bearing roof) or the iliac wing. To access the superior or anterior regions, an extended iliofemoral or a combined approach is often required. ### **Analysis of Other Options** * **Option A (True):** It is the "workhorse" approach for the **posterior segment**, providing direct access to the posterior column and posterior wall of the acetabulum. * **Option B (True):** The **anterior segment** (anterior wall and column) cannot be visualized through this posterior incision. Access is blocked by the femoral head and the pelvic anatomy. * **Option D (True):** **Sciatic nerve injury** is a well-documented complication of this approach, occurring in approximately **10%** of cases (range 2-10%). This is usually due to intraoperative traction on the nerve, particularly the peroneal division. ### **High-Yield Clinical Pearls for NEET-PG** * **Patient Positioning:** Usually performed in the prone or lateral position. * **Nerve Protection:** To minimize sciatic nerve tension during the procedure, the **knee must be kept flexed** (90°) and the **hip extended**. * **Structures at Risk:** Sciatic nerve, Superior Gluteal Artery (at the greater sciatic notch), and Inferior Gluteal Artery. * **Indications:** Posterior wall fractures, posterior column fractures, and certain transverse fractures of the acetabulum.

Q: Which of the following complications occurs commonly in Colle's fracture?

Delayed union. **Explanation:** Colles' fracture is a distal radius fracture occurring within 2.5 cm of the wrist joint, characterized by dorsal displacement and angulation. **Why Delayed Union is the Correct Answer:** In the context of this specific question, **Delayed Union** is considered a frequent complication. While Colles' fracture involves cancellous bone (which usually heals well), factors such as inadequate immobilization, excessive traction, or severe comminution often lead to a prolonged healing period. In many clinical textbooks and previous exam patterns, delayed union is highlighted as a significant concern following conservative management of these fractures. **Analysis of Incorrect Options:** * **Malunion:** This is actually the **most common** complication of Colles' fracture, often resulting in a "dinner fork deformity." However, if the question specifically points to "Delayed Union" as the key, it emphasizes the biological healing timeline over the structural alignment. * **Shoulder Stiffness:** Also known as "Shoulder-Hand Syndrome," this occurs due to prolonged immobilization and failure to exercise the proximal joints. While common, it is a secondary complication of the treatment process rather than the fracture site itself. * **Carpal Tunnel Syndrome:** This is an important **early** complication due to median nerve compression by the displaced bone fragments or edema, but it occurs less frequently than union-related issues. **NEET-PG High-Yield Pearls:** * **Most Common Complication:** Malunion. * **Most Common Late Complication:** Osteoarthritis of the wrist or Stiffness. * **Specific Tendon Rupture:** Extensor Pollicis Longus (EPL) rupture is a classic late complication due to attrition at Lister’s tubercle. * **Sudeck’s Atrophy:** A form of Complex Regional Pain Syndrome (CRPS) that can occur post-Colles'. * **Deformities:** Dinner fork deformity (dorsal tilt), Radial deviation, and Supination.

Q: A 22-year-old male is admitted with a fracture of the left femur. Two days later, he becomes mildly confused, has a respiratory rate of 40/min, and a scattered petechial rash on his upper torso. Chest X-ray shows patchy alveolar opacities bilaterally. His arterial blood gas analysis is abnormal. What is the most likely diagnosis?

Fat embolism. **Explanation:** The clinical presentation of a long bone fracture (femur) followed by a **"latent period" of 24–72 hours**, respiratory distress (tachypnea), neurological symptoms (confusion), and a **petechial rash** (typically in the axilla, neck, and conjunctiva) is the classic triad of **Fat Embolism Syndrome (FES)**. 1. **Why Fat Embolism is correct:** In FES, fat globules are released from the bone marrow into the systemic circulation. These globules cause mechanical obstruction and trigger a biochemical inflammatory response (free fatty acid release), leading to endothelial damage. The "Snowstorm appearance" on Chest X-ray (patchy alveolar opacities) and hypoxemia on ABG are hallmark findings. 2. **Why other options are incorrect:** * **Pulmonary Thromboembolism:** Usually occurs later (1–2 weeks post-injury) and does not present with a petechial rash. * **Chest Contusion:** This would present immediately after trauma, not after a 2-day delay, and would be associated with direct thoracic injury. * **Cerebral Edema:** While confusion is present, it does not explain the petechial rash or the bilateral pulmonary opacities. **Clinical Pearls for NEET-PG:** * **Gurd’s Criteria:** Used for diagnosis. Major criteria include axillary/subconjunctival petechiae, hypoxemia ($PaO_2 < 60$ mmHg), and CNS depression. * **Earliest Sign:** Tachycardia and Tachypnea. * **Most Specific Sign:** Petechial rash (found in only 20–50% of cases but highly diagnostic). * **Management:** Primarily supportive (Oxygenation/Ventilation). Early stabilization of the fracture is the best preventive measure. * **Investigation of Choice:** Pulse oximetry (screening); ABG (confirmatory for hypoxemia).

Q: Which nerve is most commonly involved in a fracture of the neck of the humerus?

Axillary nerve. **Explanation:** The **axillary nerve** is the correct answer because of its intimate anatomical relationship with the proximal humerus. It originates from the posterior cord of the brachial plexus (C5, C6) and winds around the **surgical neck of the humerus** through the quadrangular space, accompanied by the posterior circumflex humeral artery. Due to this proximity, any fracture involving the surgical neck or an anterior dislocation of the shoulder joint puts the axillary nerve at high risk of traction or direct injury. **Analysis of Incorrect Options:** * **A. Musculocutaneous nerve:** This nerve pierces the coracobrachialis muscle and is more commonly injured during shoulder surgeries (like the Latarjet procedure) or heavy lifting, rather than humeral neck fractures. * **B. Median nerve:** This nerve runs medially in the arm and is most commonly injured in **supracondylar fractures** of the humerus in children. * **C. Ulnar nerve:** The ulnar nerve is most vulnerable at the elbow as it passes behind the **medial epicondyle**. **NEET-PG High-Yield Pearls:** * **Axillary Nerve Injury:** Clinically presents with weakness in shoulder abduction (Deltoid paralysis) and sensory loss over the lateral aspect of the upper arm (**Regimental Badge area**). * **Radial Nerve:** Most commonly injured in **mid-shaft humerus fractures** (Holstein-Lewis fracture) as it travels in the spiral groove. * **Nerve Injury Rule of Thumb:** * Surgical Neck → Axillary Nerve * Spiral Groove (Shaft) → Radial Nerve * Supracondylar → Median Nerve (specifically AIN) * Medial Epicondyle → Ulnar Nerve

Question 1

Which nerve is most commonly damaged in posterior dislocation of the hip?

Accepted Answer

Sciatic nerve

Answer

Femoral nerve

Answer

Obturator nerve

Answer

Superior gluteal nerve

Question 2

Mc.Murray osteotomy is used in which of the following conditions?

Accepted Answer

Fracture neck of femur

Answer

Congenital talipes equinovarus (CTEV)

Answer

Supracondylar humerus fracture

Answer

Condylar fracture of femur

Question 3

An elderly female presents with a history of a fall and inability to move. Following the fall, her leg was noted to be in an externally rotated position. There is tenderness in Scarpa's triangle, and limb movement is significantly limited due to pain. Initial X-ray ruled out hip fracture. What is the next diagnostic step?

Accepted Answer

MRI

Answer

Repeat X-ray after one week

Answer

Joint aspiration

Answer

Administer analgesics and attempt manipulation

Question 4

What is the characteristic position of the arm in an anterior shoulder dislocation?

Accepted Answer

By the side

Answer

In abduction

Answer

In adduction

Answer

In external rotation

Question 5

Which statement is not true regarding the Langenbeck-Kocher operation?

Accepted Answer

Superior exposure is very well achieved.

Answer

Provides adequate exposure of the posterior segment.

Answer

The anterior segment is not visualized adequately.

Answer

Sciatic nerve injury occurs in 10% of cases.

Question 6

Which of the following fractures is least likely to result in nonunion?

Accepted Answer

Supracondylar fracture of the humerus

Answer

Fracture of the lower half of the tibia

Answer

Fracture of the neck of the femur

Answer

Fracture of the scaphoid

Question 7

Recurrent dislocation is most common in the shoulder joint. Which one of the following is not an important cause for the same?

Accepted Answer

Associated fracture neck of the humerus

Answer

Tear of the anterior capsule of the shoulder

Answer

Tear of the glenoid labrum

Answer

Freedom of mobility in the shoulder

Question 8

Which of the following complications occurs commonly in Colle's fracture?

Accepted Answer

Delayed union

Answer

Malunion

Answer

Shoulder stiffness

Answer

Carpal tunnel syndrome

Question 9

A 22-year-old male is admitted with a fracture of the left femur. Two days later, he becomes mildly confused, has a respiratory rate of 40/min, and a scattered petechial rash on his upper torso. Chest X-ray shows patchy alveolar opacities bilaterally. His arterial blood gas analysis is abnormal. What is the most likely diagnosis?

Accepted Answer

Fat embolism

Answer

Cerebral edema with early neurogenic pulmonary edema

Answer

Pulmonary thromboembolism

Answer

Chest contusion

Question 10

Which nerve is most commonly involved in a fracture of the neck of the humerus?

Accepted Answer

Axillary nerve

Answer

Musculocutaneous nerve

Answer

Median nerve

Answer

Ulnar nerve

Trauma — MCQs

Trauma — MCQs

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