Trauma — MCQs

Trauma Indian Medical PG Practice Questions and MCQs

Question 521: In anterior dislocation of the shoulder, which nerve is most commonly involved?

A. Radial nerve
B. Axillary nerve (Correct Answer)
C. Ulnar nerve
D. Median nerve

Explanation: **Explanation:** **Why Axillary Nerve is the Correct Answer:** The axillary nerve (C5, C6) is the most frequently injured nerve in anterior shoulder dislocations due to its unique anatomical course. It winds around the **surgical neck of the humerus** within the quadrangular space. When the humeral head displaces anteriorly and inferiorly, it stretches or compresses the nerve against the neck of the humerus. Clinically, this manifests as: * **Motor loss:** Weakness in shoulder abduction (Deltoid paralysis). * **Sensory loss:** Numbness over the lateral aspect of the upper arm, known as the **"Regimental Badge area."** **Why Other Options are Incorrect:** * **Radial Nerve:** Typically injured in fractures of the **humeral shaft** (radial groove) or "Saturday Night Palsy," leading to wrist drop. * **Ulnar Nerve:** Most commonly injured at the **elbow** (medial epicondyle) or the wrist (Guyon’s canal). * **Median Nerve:** Usually involved in supracondylar fractures of the humerus (in children) or carpal tunnel syndrome. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common type of shoulder dislocation:** Anterior (95%). 2. **Most common nerve injured:** Axillary nerve (Neuropraxia is the most common type of injury, usually recovering spontaneously). 3. **Associated Vascular Injury:** The **Axillary artery** can be injured, especially in elderly patients with atherosclerotic vessels. 4. **Hill-Sachs Lesion:** A compression fracture of the posterolateral humeral head (seen in anterior dislocation). 5. **Bankart Lesion:** Avulsion of the anteroinferior glenoid labrum. 6. **Kocher’s Method:** A classic (though now less preferred due to complications) maneuver for reduction.

Question 522: If the head of the radius is removed, what deformity will result?

A. Lengthening of limb
B. Valgus deformity (Correct Answer)
C. Varus deformity
D. No deformity

Explanation: **Explanation:** The radial head acts as a critical **secondary stabilizer** against valgus stress at the elbow. While the Medial Collateral Ligament (MCL) is the primary stabilizer, the radial head provides approximately 30% of the resistance to valgus forces by acting as a bony buttress against the capitellum. **1. Why Valgus Deformity is Correct:** When the radial head is excised, the lateral column of the elbow loses its structural support. Without this bony "strut," the forearm tends to deviate laterally under normal physiological loads, leading to a **valgus deformity**. Furthermore, the loss of the radial head can lead to proximal migration of the radius (especially if the interosseous membrane is injured), causing secondary instability at the distal radioulnar joint (Essex-Lopresti injury). **2. Why Other Options are Incorrect:** * **Lengthening of limb:** Excision of a bone segment typically leads to shortening or proximal migration, never lengthening. * **Varus deformity:** Varus stability is primarily maintained by the Lateral Collateral Ligament (LCL) complex and the trochlea-ulna articulation. Radial head loss specifically affects the lateral buttress, making varus deviation anatomically unlikely. * **No deformity:** While some patients may remain asymptomatic initially, biomechanical studies confirm that radial head excision significantly increases strain on the MCL and leads to measurable valgus instability over time. **Clinical Pearls for NEET-PG:** * **Mason Classification:** Used for radial head fractures (Type I: Undisplaced; Type II: Displaced; Type III: Comminuted; Type IV: With elbow dislocation). * **Management Rule:** In comminuted fractures, **Radial Head Replacement** is preferred over excision if there is associated MCL injury or interosseous membrane disruption to prevent valgus instability and proximal radial migration. * **Safe Zone:** For internal fixation, the "safe zone" for screw placement is a 90-degree arc (from the radial styloid to the Lister’s tubercle) where the head does not articulate with the lesser sigmoid notch.

Question 523: Fracture of the clavicle is commonest at which location?

A. Junction of the medial third and lateral two-thirds
B. Junction of the medial two-thirds and lateral third (Correct Answer)
C. Midpoint
D. Scapular end

Explanation: **Explanation:** The clavicle is the most commonly fractured bone in the human body. Anatomically, it is divided into three parts: the medial third, the middle third, and the lateral third. **Why Option B is correct:** The junction of the **medial two-thirds and lateral third** (which corresponds to the middle third of the bone) is the most common site of fracture, accounting for approximately **80% of all clavicular fractures**. This location is the weakest point of the bone for two primary reasons: 1. **Change in Curvature:** It is the transition point where the bone changes its cross-sectional shape from cylindrical (medial) to flattened (lateral). 2. **Lack of Soft Tissue Support:** This area is not reinforced by the strong coracoclavicular ligaments (lateral) or the costoclavicular ligaments (medial), making it vulnerable to indirect forces, such as a fall on an outstretched hand. **Analysis of Incorrect Options:** * **Option A:** This is a common distractor. The junction is specifically between the medial 2/3 and lateral 1/3, not the other way around. * **Option C:** While the fracture occurs in the "middle third," it specifically localizes to the junctional transition rather than the exact geometric midpoint. * **Option D:** The lateral (scapular) end accounts for only about 15% of fractures, usually involving direct trauma to the shoulder. **NEET-PG High-Yield Pearls:** * **First bone to ossify** in the fetus (5th–6th week) and the only long bone to ossify in **membrane** (except for its ends). * **Mechanism of Injury:** Most commonly a fall on the outstretched hand (FOOSH) or a direct blow to the shoulder. * **Deformity:** In a middle-third fracture, the proximal fragment is pulled **upward** by the Sternocleidomastoid muscle, while the distal fragment drops **downward** due to the weight of the arm. * **Management:** Most are treated conservatively with a **Figure-of-8 bandage** or a triangular sling.

Question 524: A patient develops Saturday Night Palsy after consuming alcohol and sleeping overnight with an arm in a dependent position. Which of the following best describes the clinical manifestations of this condition?

A. Neuropraxia (Correct Answer)
B. Axonotmesis
C. Neurotmesis
D. Necroptosis

Explanation: **Explanation:** **Saturday Night Palsy** is a classic clinical scenario of **Radial Nerve compression** at the spiral groove of the humerus. This occurs when a person falls into a deep sleep (often due to alcohol intoxication) with their arm draped over a hard edge, such as a chair back, leading to prolonged pressure on the nerve. **Why Neuropraxia is correct:** According to Seddon’s classification of nerve injuries, **Neuropraxia** is the mildest form. It involves a temporary physiological conduction block due to focal demyelination, without any physical disruption of the axon or the connective tissue sheath. In Saturday Night Palsy, the pressure causes transient ischemia and myelin dysfunction. Since the axon remains intact, Wallerian degeneration does not occur, and the patient typically experiences a full recovery within weeks as the myelin repairs. **Why the other options are incorrect:** * **Axonotmesis:** This involves disruption of the axon but the endoneurial sheath remains intact. It leads to Wallerian degeneration and requires a much longer recovery time (1mm/day). * **Neurotmesis:** This is the most severe injury where both the axon and the entire nerve sheath are completely severed. Recovery is impossible without surgical intervention. * **Necroptosis:** This is a programmed form of inflammatory cell death (a hybrid of necrosis and apoptosis) and is not a classification of peripheral nerve injury. **NEET-PG High-Yield Pearls:** * **Clinical Presentation:** "Wrist drop" with "Finger drop," but the **Triceps** function is usually **spared** because the nerve branches to the triceps arise proximal to the spiral groove. * **Sensory Loss:** Typically found in the small area of the first dorsal web space. * **Management:** Conservative (cock-up splint and physiotherapy) as the prognosis for Neuropraxia is excellent. * **Honeymoon Palsy:** A similar neuropraxic injury of the radial nerve caused by another person sleeping on the patient's arm.

Question 525: What is the treatment of choice for a fracture neck of humerus in a 70-year-old male?

A. Analgesic with an arm sling (Correct Answer)
B. U-slab
C. Arthroplasty
D. Open reduction and internal fixation

Explanation: **Explanation:** The treatment of choice for a fracture of the neck of the humerus in an elderly patient (70 years old) is **conservative management** using an **analgesic with an arm sling** (or shoulder immobilizer). **1. Why the correct answer is right:** Most proximal humerus fractures in the elderly are **impacted, minimally displaced (Neer Stage I)**, and occur due to osteoporotic bone. In this age group, the primary goal is functional recovery rather than anatomical perfection. Early mobilization is crucial to prevent **shoulder stiffness (Adhesive Capsulitis)**. An arm sling provides sufficient stability for the fracture to heal while allowing for early pendulum exercises (Codman’s exercises) within 1–2 weeks. **2. Why the incorrect options are wrong:** * **U-Slab (B):** This is the treatment of choice for **humeral shaft fractures**, not neck fractures. It does not provide adequate immobilization for the proximal humerus and is cumbersome for elderly patients. * **Arthroplasty (C):** Hemiarthroplasty or Reverse Total Shoulder Arthroplasty is reserved for complex, severely comminuted 4-part fractures or fracture-dislocations where the blood supply to the head is compromised (risk of AVN). It is not the first-line treatment for general neck fractures. * **Open Reduction and Internal Fixation (D):** Surgery (e.g., PHILOS plating) is generally preferred in younger patients with displaced fractures. In the elderly, poor bone quality (osteoporosis) increases the risk of screw pull-out and surgical complications. **Clinical Pearls for NEET-PG:** * **Most common complication:** Stiffness of the shoulder (Adhesive Capsulitis). * **Neer’s Classification:** Based on the displacement of four segments (Greater tuberosity, Lesser tuberosity, Shaft, and Head). A part is considered "displaced" if there is >1 cm distraction or >45° angulation. * **Nerve Injury:** The **Axillary nerve** is the most commonly injured nerve in proximal humerus fractures/dislocations. * **Early Mobilization:** Codman’s pendulum exercises are the hallmark of rehabilitation for these fractures.

Question 526: A child presented with a fall on an outstretched hand with the elbow in full extension. On examination there is pain and swelling over his right elbow. What is the probable diagnosis?

A. Fracture of the olecranon
B. Posterior dislocation of the elbow
C. Supracondylar fracture of the humerus (Correct Answer)
D. Fracture of both bones of the forearm

Explanation: ### Explanation **Correct Option: C. Supracondylar fracture of the humerus** **Mechanism and Concept:** Supracondylar fracture of the humerus is the most common elbow fracture in children (peak age 5–8 years). The classic mechanism is a **fall on an outstretched hand (FOOSH) with the elbow in extension**. In this position, the olecranon process is forced into the olecranon fossa, acting as a fulcrum that causes the thin supracondylar bone to snap. This results in an **extension-type** fracture (95% of cases), where the distal fragment is displaced posteriorly. **Analysis of Incorrect Options:** * **A. Fracture of the olecranon:** Rare in children; usually occurs due to a direct blow to the point of the elbow or a forceful contraction of the triceps. * **B. Posterior dislocation of the elbow:** While the mechanism (FOOSH) is similar, dislocations are much more common in **adults**. In children, the supracondylar area is physiologically weaker than the joint ligaments, making a fracture far more likely than a dislocation. * **D. Fracture of both bones of the forearm:** While FOOSH can cause forearm fractures, the clinical presentation specifically mentions pain and swelling **over the elbow**, pointing toward a periarticular injury. **NEET-PG High-Yield Pearls:** * **Clinical Sign:** On examination, the **three-point bony relationship** (medial epicondyle, lateral epicondyle, and olecranon) is **maintained** in supracondylar fractures but **disturbed** in elbow dislocations. * **Complications:** The most serious acute complication is injury to the **Brachial artery** or **Median nerve** (specifically the Anterior Interosseous Nerve). * **Late Sequel:** **Gunstock deformity** (Cubitus varus) is the most common late complication due to malunion. * **Emergency:** Always check the radial pulse to rule out **Volkmann’s Ischemic Contracture**.

Question 527: A female on steroids developed hip pain. Investigations show evidence of avascular necrosis of the head of the femur. What is the most common fracture site in this patient?

A. Subcapital region
B. Transcervical region
C. Subchondral region (Correct Answer)
D. Trochanteric region

Explanation: **Explanation:** The correct answer is **C. Subchondral region.** **Pathophysiology & Mechanism:** The patient presents with **Avascular Necrosis (AVN)** of the femoral head, likely secondary to long-term steroid use. In AVN, the underlying pathology is the death of osteocytes due to compromised blood supply. As the necrotic bone fails to repair itself, it loses its structural integrity. The mechanical stress of weight-bearing leads to **microfractures** specifically in the **subchondral region** (the layer of bone just beneath the articular cartilage). Radiologically, this manifests as the **"Crescent Sign,"** which represents a subchondral fracture or separation of the cartilage from the necrotic bone. This is a hallmark of Ficat and Arlet Stage II/III AVN and precedes the eventual collapse of the femoral head. **Analysis of Incorrect Options:** * **A & B (Subcapital and Transcervical):** These are types of intracapsular femoral neck fractures. While they can *cause* AVN by disrupting the medial circumflex femoral artery, they are not the *result* of steroid-induced AVN. * **D (Trochanteric region):** This is an extracapsular site. Fractures here are typically related to osteoporosis in the elderly or high-energy trauma, not the localized ischemic necrosis seen in AVN. **Clinical Pearls for NEET-PG:** * **Most common cause of AVN:** Trauma (Fracture neck of femur). * **Most common non-traumatic cause:** Alcoholism and Steroid use. * **Earliest Investigation:** MRI (shows marrow edema; T1-weighted images show low signal intensity). * **Crescent Sign:** Pathognomonic for subchondral collapse in AVN (best seen on X-ray/CT). * **Treatment:** Core decompression is preferred in early stages (Ficat I & II) to reduce intraosseous pressure.

Question 528: Kocher Langenbeck approach for emergency acetabular fixation is indicated in all of the following situations, EXCEPT:

A. Open fracture
B. Progressive sciatic nerve injury (Correct Answer)
C. Recurrent dislocation in spite of closed reduction and traction
D. Open irrigation and debridement of the hip joint

Explanation: **Explanation:** The **Kocher-Langenbeck approach** is the standard posterior approach to the acetabulum, primarily used for fractures involving the posterior wall or posterior column. While most acetabular surgeries are elective (delayed 3–5 days for stabilization), certain "emergency" indications exist. **Why "Progressive Sciatic Nerve Injury" is the correct answer:** In the setting of an acetabular fracture with a progressive sciatic nerve deficit, the primary goal is to decompress the nerve. If the injury is caused by a **dislocated femoral head** or **bone fragments** compressing the nerve, the first step is **emergency closed reduction**. If the deficit persists or progresses after reduction, surgical exploration is indicated. However, the Kocher-Langenbeck approach itself is not the "indication" for the emergency fixation; rather, the nerve injury is often a contraindication to immediate aggressive internal fixation due to the risk of further iatrogenic trauma during retraction. **Analysis of Incorrect Options:** * **Open Fractures (A):** These are surgical emergencies requiring immediate irrigation, debridement, and often stabilization to prevent osteomyelitis. * **Recurrent Dislocation (C):** If the hip remains unstable despite traction and closed reduction (usually due to a large posterior wall fragment), emergency ORIF is required to maintain joint congruity and prevent femoral head necrosis. * **Open Irrigation/Debridement (D):** Necessary in cases of a "dirty" joint (e.g., intra-articular debris or infection), where the posterior approach provides excellent access to the joint space. **High-Yield Clinical Pearls for NEET-PG:** * **Most common approach for Acetabulum:** Kocher-Langenbeck (Posterior). * **Ilioinguinal Approach:** Used for anterior column/wall fractures. * **Sciatic Nerve:** The peroneal component is most commonly injured in posterior acetabular trauma. * **Matta’s Criteria:** Used to assess the quality of acetabular reduction (Displacement <1mm is considered excellent).

Question 529: Vascular injury is common in which fracture of the following?

A. Lower end of humerus (Correct Answer)
B. Lower end of radius
C. Upper end of femur
D. Upper end of radius

Explanation: **Explanation:** The correct answer is **A. Lower end of humerus**. **1. Why it is correct:** Fractures of the lower end of the humerus, specifically **Supracondylar fractures (Extension type)**, are notorious for vascular complications. The proximal fracture fragment is displaced anteriorly, where it can easily impinge upon or lacerate the **Brachial Artery**. This injury can lead to arterial spasm or thrombosis, potentially resulting in **Volkmann’s Ischemic Contracture (VIC)**—a surgical emergency. **2. Analysis of incorrect options:** * **Lower end of radius (Colles’ fracture):** While common, it is more frequently associated with nerve injuries (Median nerve) or tendon ruptures (Extensor Pollicis Longus) rather than major vascular compromise. * **Upper end of femur:** These fractures (Neck of femur or Intertrochanteric) are associated with **Avascular Necrosis (AVN)** of the femoral head due to disruption of the retinacular vessels, but acute major limb-threatening vascular injury is rare compared to the humerus. * **Upper end of radius:** Fractures of the radial head or neck are more likely to cause restricted forearm rotation or injury to the **Posterior Interosseous Nerve (PIN)**. **3. Clinical Pearls for NEET-PG:** * **Most common vascular injury in Supracondylar fracture:** Brachial Artery. * **Most common nerve injury in Supracondylar fracture:** Median nerve (specifically the Anterior Interosseous Nerve/AIN). * **The "5 Ps" of Ischemia:** Pain (earliest sign), Pallor, Pulselessness, Paresthesia, and Paralysis. * **High-yield association:** Knee dislocation is the lower limb equivalent most commonly associated with vascular injury (**Popliteal Artery**).

Question 530: Fracture of the lateral condyle of the humerus is typically seen in which age group?

A. 2-3 years
B. 5-15 years (Correct Answer)
C. 15-25 years
D. 35-45 years

Explanation: Fracture of the lateral condyle of the humerus is the **second most common elbow fracture** in children (after supracondylar fractures). **1. Why 5-15 years is correct:** This injury is primarily a pediatric fracture. The peak incidence occurs between **5 and 10 years of age**. During this period, the lateral condyle is largely cartilaginous and represents a weak point in the elbow's structural integrity. The mechanism usually involves a fall on an outstretched hand with the forearm in supination (pull-off injury by the extensor muscles) or a varus force (push-off injury by the radius) [1]. Because it involves the growth plate, it is classified as a **Salter-Harris Type IV injury** [1]. **2. Why other options are incorrect:** * **2-3 years:** While possible, the ossification center of the capitellum (which forms the lateral condyle) is just beginning to appear, and the mechanism of high-energy falls is less common in toddlers compared to school-aged children. * **15-25 years & 35-45 years:** In adolescents and adults, the growth plates have fused. Trauma to the elbow in these age groups more commonly results in radial head fractures, olecranon fractures, or elbow dislocations rather than isolated physeal condylar fractures. **Clinical Pearls for NEET-PG:** * **Milch Classification:** Used to categorize these fractures based on whether the fracture line passes lateral (Type I) or medial (Type II) to the trochlear groove. * **"The Fracture of Wise Men":** It is notoriously difficult to diagnose on X-ray because the fragment is often largely cartilaginous and appears smaller than it actually is [1]. * **Complications:** If missed or inadequately treated, it leads to **Non-union**, which causes **Cubitus Valgus** deformity. This deformity can result in delayed **Tardy Ulnar Nerve Palsy** years later.

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Open Fractures

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Fractures in Children

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Fracture Complications

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Nonunion and Malunion

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Trauma — MCQs

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