Trauma Practice Questions

Q: Which nerve is commonly injured due to a lunate dislocation?

Median nerve. **Explanation:** The **lunate** is the most commonly dislocated carpal bone. In a lunate dislocation, the lunate is displaced **volarly** (anteriorly) into the carpal tunnel. Because the carpal tunnel is a rigid space, this displacement directly compresses the **median nerve**, which lies immediately superficial to the lunate. This can lead to acute carpal tunnel syndrome, presenting with paresthesia in the lateral three and a half fingers and weakness of the thenar muscles. **Analysis of Incorrect Options:** * **Radial Nerve:** This nerve travels along the posterior compartment of the arm and the lateral aspect of the forearm. It does not pass through the carpal tunnel and is more commonly injured in humerus shaft fractures (Holstein-Lewis fracture). * **Axillary Nerve:** This nerve is located in the shoulder region. It is most frequently injured during anterior shoulder dislocations or surgical neck of the humerus fractures. * **Ulnar Nerve:** While the ulnar nerve passes through the wrist, it travels via **Guyon’s canal**, which is medial to the carpal tunnel. It is more commonly injured in hook of hamate fractures or distal radius fractures, but not typically in lunate dislocations. **Clinical Pearls for NEET-PG:** * **"Spilled Teacup" Sign:** On a lateral X-ray, the lunate loses its concave relationship with the capitate and tilts volarly, resembling a tipped cup. * **Terry Thomas Sign:** Associated with **scapholunate dissociation** (widening of the gap >3mm), not lunate dislocation. * **Perilunate vs. Lunate Dislocation:** In perilunate dislocation, the lunate remains in line with the radius while other carpals displace; in lunate dislocation, the lunate itself is displaced. Both can cause median nerve injury.

Q: What is the management for the depicted condition?

Internal fixation with compression plating. ***Internal fixation with compression plating*** - **Both-bone forearm fractures** require anatomical reduction to restore the **radial bow** and maintain proper **radioulnar relationship** for forearm rotation. - **Dynamic compression plating** provides rigid fixation allowing early mobilization and optimal functional outcomes in displaced diaphyseal fractures. *Closed reduction* - Inadequate for **displaced both-bone fractures** as it cannot maintain anatomical alignment and **radial bow**. - High risk of **loss of reduction** and malunion leading to **restricted forearm rotation** and functional impairment. *Cast immobilization* - Cannot maintain reduction in **unstable diaphyseal fractures** of both radius and ulna. - Risk of **compartment syndrome** from swelling within the cast and poor functional outcomes due to malunion. *External fixation* - Reserved for **open fractures** with severe soft tissue damage or **infected nonunions**. - Does not provide adequate **rotational control** and anatomical restoration required for optimal forearm function.

Q: A patient presents with a fall on an outstretched hand. An X-ray is shown below. Which of the following vessels is most likely involved?

Brachial artery. ***Brachial artery*** - Fall on outstretched hand (FOOSH) typically causes a **supracondylar fracture of the humerus**, where the **brachial artery** runs directly anterior to the elbow joint and is vulnerable to injury from the proximal fracture fragment. - The **brachial artery** is the main vessel crossing the elbow anteriorly, making it the most commonly injured vessel in supracondylar fractures, potentially causing **compartment syndrome** or **Volkmann's ischemic contracture**. *Ulnar artery* - The **ulnar artery** is located more distally in the forearm and medially, making it less vulnerable to injury in supracondylar fractures. - Ulnar artery injuries are more commonly associated with **distal radius fractures** or **direct trauma** to the medial forearm. *Radial artery* - The **radial artery** runs laterally in the forearm and is more commonly injured with **distal radius fractures** (Colles' fracture) rather than supracondylar fractures. - It passes through the **anatomical snuffbox** and is not in the direct path of injury from proximal humeral fracture fragments. *Cubital vein* - The **cubital vein** is a superficial venous structure in the **antecubital fossa** and is not typically injured in supracondylar fractures. - Venous injuries are less clinically significant than arterial injuries and would not cause the **ischemic complications** associated with supracondylar fractures.

Q: AP and lateral views of the wrist are provided. What is the diagnosis?

Galeazzi fracture. ***Galeazzi fracture*** - Characterized by a **fracture of the distal third of the radius** with **dislocation of the distal radioulnar joint (DRUJ)**. - **Mnemonic**: "**GRU**" - **G**aleazzi involves **R**adial fracture with **U**lnar dislocation at the wrist. *Monteggia fracture* - Involves **fracture of the ulnar shaft** with **dislocation of the radial head** at the elbow. - **Mnemonic**: "**MURL**" - **M**onteggia involves **U**lnar fracture with **R**adial dislocation at the e**L**bow. *Smith fracture* - **Volarly angulated distal radius fracture** (reverse of Colles), often called "**reverse Colles fracture**". - Results from **flexion mechanism** and shows **volar displacement** of the distal fragment on lateral view. *Colles fracture* - **Dorsally angulated distal radius fracture** with **dorsal displacement** of the distal fragment. - Shows classic **dinner fork deformity** clinically and **dorsal angulation** on lateral X-ray view.

Q: Volkmann's Ischaemic Contracture is due to which of the following?

Ischaemic vascular injury to the muscle. **Explanation:** **Volkmann’s Ischaemic Contracture (VIC)** is the permanent end-stage sequela of an untreated or inadequately treated **Acute Compartment Syndrome**, most commonly following a Supracondylar fracture of the humerus in children. 1. **Why Option D is Correct:** The primary pathology is **ischaemic necrosis of the forearm muscles** (specifically the deep flexor compartment). When tissue pressure within the osteofascial compartment exceeds capillary perfusion pressure, it leads to muscle infarction. The infarcted muscle is eventually replaced by **fibrous tissue**, which undergoes contraction, leading to the characteristic deformities. The **Flexor Digitorum Profundus (FDP)** and **Flexor Pollicis Longus (FPL)** are the most commonly affected muscles. 2. **Why Other Options are Incorrect:** * **Options A & B:** While nerve palsies (Median and Ulnar) can occur as a secondary result of ischaemia or compression within the compartment, they are not the *cause* of the contracture. The contracture itself is a myogenic process (muscle fibrosis). * **Option C:** Contracture of the palmar fascia refers to **Dupuytren’s Contracture**, a completely different fibroproliferative condition unrelated to ischaemia. **Clinical Pearls for NEET-PG:** * **Characteristic Deformity:** Wrist flexion, MCP joint hyperextension, and IP joint flexion (Claw-like hand). * **Volkmann’s Sign:** Passive extension of the fingers is restricted and painful when the wrist is kept extended; however, fingers can be extended if the wrist is flexed (as this relaxes the fibrotic flexor tendons). * **Earliest Sign:** Pain on passive stretching of the affected muscles (out of proportion to the injury). * **Infant/Neonatal VIC:** Usually presents as a sentinel skin lesion (bullae/eschar) at birth.

Q: Stress fracture is treated by:

Cast immobilization. **Explanation:** **Stress fractures** (also known as fatigue fractures) occur due to repetitive submaximal loading on a bone, where the rate of bone resorption by osteoclasts exceeds the rate of bone formation by osteoblasts. 1. **Why Cast Immobilization is Correct:** While minor stress fractures in non-weight-bearing bones may sometimes be managed with rest alone, the standard orthopedic management for a confirmed stress fracture—especially in weight-bearing bones (like the tibia or metatarsals)—is **Cast Immobilization**. This provides rigid stabilization, eliminates the repetitive mechanical strain, and prevents the progression of a "stress reaction" into a complete cortical break or displaced fracture. 2. **Why Other Options are Incorrect:** * **Rest:** While "activity modification" is part of the treatment, simple rest without immobilization is often insufficient for high-risk stress fractures and may lead to non-union or recurrence. * **Closed Reduction:** This is used for displaced fractures to restore anatomical alignment. Stress fractures are, by definition, non-displaced micro-cracks; therefore, there is no displacement to "reduce." * **Internal Fixation:** This is a second-line treatment reserved only for "high-risk" stress fractures (e.g., tension side of the femoral neck, Jones fracture, or navicular bone) that have failed conservative management. **NEET-PG High-Yield Pearls:** * **Most common site:** Tibia (overall), followed by the 2nd and 3rd metatarsals (**March Fracture**). * **Imaging:** X-rays are often negative in the first 2–3 weeks. **MRI** is the gold standard and the most sensitive investigation for early detection (shows marrow edema). * **Triple Phase Bone Scan:** Shows "hot spots" but is less specific than MRI. * **Female Athlete Triad:** Disordered eating, amenorrhea, and osteoporosis are major risk factors for stress fractures.

Q: A 20-year-old male presents with anterior shoulder dislocation. This injury is usually caused as a combination of which of the following?

Abduction and external rotation. ### **Explanation** The shoulder joint is the most commonly dislocated joint in the body, with **anterior dislocation** accounting for over 95% of cases. **1. Why Abduction and External Rotation is Correct:** The mechanism of injury typically involves a fall on an outstretched hand or a direct blow to the arm when it is in a position of **abduction, external rotation, and extension**. In this position, the humeral head is levered out of the glenoid cavity, pushing against the relatively weak anterior capsule and glenohumeral ligaments. This "throwing motion" position puts maximum stress on the anterior stabilizers, leading to the displacement of the humeral head anteriorly and inferiorly. **2. Why the Other Options are Incorrect:** * **Adduction and Internal Rotation (Option D):** This is the classic mechanism for **Posterior Shoulder Dislocation**. It often occurs during seizures or electric shocks, where the powerful internal rotators (Latissimus dorsi, Pectoralis major) overpower the external rotators. * **Abduction and Internal Rotation (Option C):** This position is biomechanically stable for the anterior capsule and is not a recognized mechanism for primary dislocation. * **Adduction and External Rotation (Option B):** This position does not provide the necessary leverage to force the humeral head out of the glenoid labrum. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common type:** Subcoracoid (a subtype of anterior dislocation). * **Associated Nerve Injury:** **Axillary nerve** (tested by checking sensation over the "Regimental Badge" area). * **Radiological Signs:** **Hill-Sachs lesion** (compression fracture of the posterolateral humeral head) and **Bankart lesion** (avulsion of the anteroinferior glenoid labrum). * **Classic Sign:** Flattening of the shoulder contour (loss of rounded appearance) and positive **Dugas Test**.

Q: Functional cast bracing is NOT used in which of the following fractures?

Thoracolumbar spine. **Explanation:** **Functional Cast Bracing (Sarmiento Bracing)** is based on the principle of **hydrostatic pressure**. It uses the surrounding soft tissues and muscle bulk to stabilize a fracture while allowing early joint movement. This promotes osteogenesis and prevents "fracture disease" (joint stiffness and muscle atrophy). **Why Thoracolumbar Spine is the Correct Answer:** Functional cast bracing is specifically designed for **long bone fractures** where the surrounding muscle envelope can be compressed to provide stability. The **Thoracolumbar spine** lacks this circumferential muscle envelope required for hydrostatic stabilization. Spinal fractures require rigid immobilization (like a Taylor’s brace or ASH brace) or surgical stabilization to protect the spinal cord, as functional bracing would allow micro-motion that is dangerous in the axial skeleton. **Analysis of Other Options:** * **Humerus (A):** The Sarmiento brace is the gold standard for non-operative management of mid-shaft humeral fractures. It relies on the deltoid and triceps bulk. * **Tibia (B):** Functional bracing is commonly used for distal third tibial fractures after initial swelling subsides, allowing knee and ankle motion. * **Ulna (C):** Isolated ulnar shaft fractures (Nightstick fractures) are frequently treated with functional bracing as the radius acts as a natural splint. **High-Yield Clinical Pearls for NEET-PG:** * **Founder:** Augusto Sarmiento. * **Mechanism:** Hydrostatic pressure in soft tissues. * **Prerequisite:** The fracture must be **stable** and have **intact soft tissue** (muscle) coverage. * **Contraindications:** Massive soft tissue loss, unstable joints, or fractures requiring rigid internal fixation (e.g., intra-articular fractures).

Question 1

Which nerve is commonly injured due to a lunate dislocation?

Accepted Answer

Median nerve

Answer

Radial nerve

Answer

Axillary nerve

Answer

Ulnar nerve

Question 2

Which of the following fractures is known for non-union?

Accepted Answer

Colles' fracture

Answer

Scaphoid fracture

Answer

Lateral condyle humerus fracture

Answer

Femoral neck fracture

Question 3

What is the recommended re-implantation time for a lower limb injury?

Accepted Answer

8 hours

Answer

6 hours

Answer

4 hours

Answer

10 hours

Question 4

What is the management for the depicted condition?

Accepted Answer

Internal fixation with compression plating

Answer

Closed reduction

Answer

Cast immobilization

Answer

External fixation

Question 5

A patient presents with a fall on an outstretched hand. An X-ray is shown below. Which of the following vessels is most likely involved?

Accepted Answer

Brachial artery

Answer

Ulnar artery

Answer

Radial artery

Answer

Cubital vein

Question 6

AP and lateral views of the wrist are provided. What is the diagnosis?

Accepted Answer

Galeazzi fracture

Answer

Monteggia fracture

Answer

Smith fracture

Answer

Colles fracture

Question 7

Volkmann's Ischaemic Contracture is due to which of the following?

Accepted Answer

Ischaemic vascular injury to the muscle

Answer

Injury to ulnar and median nerve

Answer

Injury to median nerve alone

Answer

Contracture of the palmar fascia

Question 8

Stress fracture is treated by:

Accepted Answer

Cast immobilization

Answer

Rest

Answer

Closed reduction

Answer

Internal fixation

Question 9

A 20-year-old male presents with anterior shoulder dislocation. This injury is usually caused as a combination of which of the following?

Accepted Answer

Abduction and external rotation

Answer

Adduction and external rotation

Answer

Abduction and internal rotation

Answer

Adduction and internal rotation

Question 10

Functional cast bracing is NOT used in which of the following fractures?

Accepted Answer

Thoracolumbar spine

Answer

Humerus

Answer

Tibia

Answer

Ulna

Trauma — MCQs

Trauma — MCQs

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