Trauma Practice Questions

Q: What is the most important factor in fracture healing?

Immobilization. **Explanation:** The primary requirement for fracture healing is **Immobilization**. For a fracture to heal, the "callus" (the bridge of new bone) must form across the gap. Excessive movement at the fracture site creates shear forces that disrupt the delicate capillary ingrowth and the formation of the fibrocartilaginous bridge. If the fracture site is not sufficiently immobilized, the body may form a "non-union" or a "pseudoarthrosis" (false joint) instead of solid bone. **Analysis of Options:** * **A. Good alignment:** While alignment is important for functional recovery and preventing deformity (malunion), a fracture can still heal (unite) even if it is poorly aligned. * **B. Organization of blood clot:** While the hematoma is the first stage of fracture healing and provides a fibrin scaffold, it is not the *most* important factor. Healing can still occur in the absence of a significant clot (e.g., in primary bone healing via internal fixation). * **C. Accurate reduction and 100% apposition:** This is a common misconception. While 100% apposition is ideal, many fractures (like the clavicle or ribs) heal perfectly well with minimal contact or significant displacement, provided they are kept still. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Bone Healing:** Occurs with absolute stability (e.g., compression plating). There is **no callus formation**. * **Secondary Bone Healing:** Occurs with relative stability (e.g., POP cast, intramedullary nailing). This involves the classic stages: Hematoma → Inflammation → Soft Callus → Hard Callus → Remodeling. * **The "Rule of Two":** For adequate immobilization, a cast should generally include the joint above and the joint below the fracture site. * **Most common cause of Non-union:** Inadequate immobilization or poor blood supply.

Q: What is the X-ray diagnosis?

Supracondylar humerus fracture. ***Supracondylar humerus fracture*** - The **anterior humeral line** does not pass through the middle third of the **capitellum**, a key radiographic sign for supracondylar fractures. - This is the **most common pediatric elbow fracture**, typically occurring after a fall on an outstretched hand with hyperextension injury. *Olecranon fracture* - Would show a clear **fracture line** through the **olecranon process** of the ulna, which is not present here. - Typically causes inability to actively extend the elbow due to **triceps muscle disruption**. *Humerus shaft fracture* - The fracture line would be located in the **mid-shaft** of the humerus, not near the elbow joint. - Associated with **radial nerve palsy** causing wrist drop and loss of thumb extension. *Elbow dislocation* - Shows **displacement** of the radius and ulna relative to the humerus with loss of normal joint alignment. - The **radiocapitellar line** would not pass through the center of the capitellum in true dislocations.

Q: A Tillaux fracture involves which part of the bone?

Lower end tibia. **Explanation:** A **Tillaux fracture** is a specific type of avulsion fracture involving the **anterolateral tubercle of the distal (lower end) tibia**. **1. Why Option A is correct:** The fracture occurs due to an external rotation force of the foot, which puts extreme tension on the **Anterior Inferior Tibiofibular Ligament (AITFL)**. Instead of the ligament tearing, it pulls off a bony fragment from its insertion site on the lateral aspect of the distal tibia. In pediatric populations, this is known as a **Juvenile Tillaux fracture** (a Salter-Harris Type III injury), occurring because the medial part of the distal tibial growth plate closes before the lateral part, leaving the lateral side vulnerable to avulsion. **2. Why the other options are incorrect:** * **Upper end tibia (B):** Fractures here are typically Tibial Plateau fractures or Segond fractures (avulsion of the lateral capsule). * **Lower end femur (C):** Common injuries include Supracondylar or Intercondylar fractures, often due to high-energy trauma. * **Upper end femur (D):** This involves Neck of Femur or Intertrochanteric fractures, common in geriatric falls or high-impact trauma. **Clinical Pearls for NEET-PG:** * **Mechanism:** Forced external rotation of the ankle. * **Radiology:** Best seen on an AP view of the ankle; however, **CT scans** are the gold standard to assess the degree of displacement and articular involvement. * **Management:** Displaced fractures (>2mm) require Open Reduction and Internal Fixation (ORIF) to prevent secondary osteoarthritis. * **Differentiate:** Do not confuse this with a **Wagstaffe-Le Fort fracture**, which is an avulsion of the AITFL from the **fibula** rather than the tibia.

Q: What is a crescent fracture?

Fracture of the iliac crest. **Explanation:** A **Crescent fracture** is a specific type of unstable pelvic ring injury. It is a fracture-dislocation of the sacroiliac (SI) joint where a vertical fracture line runs through the posterior portion of the **iliac crest** (the posterior superior iliac spine), leaving a "crescent-shaped" fragment attached to the sacrum via the posterior SI ligaments. **Analysis of Options:** * **A. Fracture of the iliac crest (Correct):** This is the defining feature of the crescent fracture. It typically occurs due to a Lateral Compression (LC) injury (Young-Burgess Type II). The force causes the iliac bone to fracture posteriorly while the anterior SI ligaments are disrupted. * **B. Fracture of the coccyx:** These are usually isolated injuries resulting from a direct fall on the buttocks and are not associated with the "crescent" eponym. * **C. Fracture of the calcaneum:** Common eponyms for calcaneal fractures include "Lover’s fracture" or "Don Juan fracture." * **D. Fracture of the Atlas:** A fracture of the C1 vertebra is known as a **Jefferson fracture**. **High-Yield Clinical Pearls for NEET-PG:** * **Classification:** Crescent fractures are categorized under the **Young-Burgess classification** as **Lateral Compression Type II (LC-II)**. * **Stability:** These are considered rotationally unstable but vertically stable injuries. * **Management:** Surgical stabilization (ORIF) is often required to restore the pelvic ring integrity and prevent long-term gait abnormalities or chronic pain. * **Radiology:** On an AP view of the pelvis, look for a vertical fracture line through the ilium that spares the sacroiliac joint surface itself.

Q: Tinel's sign indicates which of the following?

Regeneration of nerves. **Explanation:** **Tinel’s sign** is a clinical indicator of **nerve regeneration**. It is elicited by percussing along the course of a damaged nerve. A positive sign is characterized by a "pins and needles" sensation or tingling in the distal distribution of the nerve. 1. **Why Regeneration is Correct:** When a peripheral nerve undergoes repair, the regenerating axonal sprouts (growth cones) are thin and lack a mature myelin sheath. These immature axons are **hyperexcitable** and highly sensitive to mechanical pressure. Percussing these regenerating fibers triggers an electrical impulse, signaling that the nerve is successfully growing distally (typically at a rate of 1 mm/day). 2. **Why Other Options are Incorrect:** * **Atrophy of nerves:** Atrophy refers to the wasting of muscles or degeneration of nerve tissue, which does not produce an evocative sensory response to percussion. * **Neuroma:** While tapping a neuroma (a disorganized bulb of nerve fibers) can cause pain, Tinel’s sign specifically refers to the *progression* of the tingling sensation down the limb, which tracks recovery rather than just the presence of a lesion. * **Injury to nerve:** Immediately after an injury (like neurotmesis), Tinel’s sign is absent. It only becomes positive once regeneration begins. **NEET-PG High-Yield Pearls:** * **Hoffmann-Tinel Sign:** The full name of the sign. * **Advancing Tinel’s Sign:** If the point of maximum tingling moves distally over time, it is a **good prognostic sign** indicating recovery. * **Static Tinel’s Sign:** If the tingling remains at the site of injury and does not move distally, it suggests a **neuroma** and poor regenerative progress. * **Carpal Tunnel Syndrome:** Tinel’s sign is also used diagnostically here to indicate nerve compression/irritation at the wrist.

Q: What is Neurapraxia?

Reversible physiological nerve conduction block. **Explanation:** **Neurapraxia** is the mildest form of nerve injury according to the **Seddon Classification**. It is characterized by a **reversible physiological conduction block** without any anatomical disruption of the axon or its connective tissue coverings (endoneurium, perineurium, or epineurium). 1. **Why Option D is Correct:** The underlying mechanism is typically focal demyelination or local ischemia caused by mild compression or traction. Since the axon remains intact, there is no Wallerian degeneration. Once the pressure is relieved or the myelin is repaired, nerve conduction is fully restored. 2. **Why Other Options are Incorrect:** * **Option A (Complete division):** This describes **Neurotmesis**, the most severe form of injury where the entire nerve trunk is severed. Recovery is impossible without surgical intervention. * **Option B (Axonal interruption):** This describes **Axonotmesis**. Here, the axon is damaged, leading to Wallerian degeneration, but the supporting connective tissue framework remains intact, allowing for guided regeneration. * **Option C (Irreversible injury):** Neurapraxia is inherently **reversible**. Recovery is usually spontaneous and rapid, occurring within days to a few weeks (typically 3–6 weeks). **High-Yield Clinical Pearls for NEET-PG:** * **Wallerian Degeneration:** Absent in Neurapraxia; present in Axonotmesis and Neurotmesis. * **Tinel’s Sign:** Negative in Neurapraxia (as there is no regenerating axonal bud); Positive in Axonotmesis. * **Common Example:** "Saturday Night Palsy" (radial nerve compression) is a classic clinical presentation of neurapraxia. * **EMG/NCV:** In neurapraxia, there is a conduction block at the site of injury, but distal stimulation remains normal.

Question 1

What is a Colles' fracture a fracture of?

Accepted Answer

Intra-articular fracture of the distal end of the radius with carpal bone subluxation

Answer

Distal end humerus fracture

Answer

Extra-articular fracture of the distal end of the radius

Answer

Intra-articular fracture of the distal end of the radius

Question 2

Arrange the following nerves according to the incidence of their involvement in a supracondylar fracture of the humerus:

Accepted Answer

Anterior interosseous nerve, Median nerve, Radial nerve, Ulnar nerve

Answer

Anterior interosseous nerve, Median nerve, Ulnar nerve, Radial nerve

Answer

Median nerve, Anterior interosseous nerve, Radial nerve, Ulnar nerve

Answer

Ulnar nerve, Median nerve, Radial nerve, Anterior interosseous nerve

Question 3

What is the most important factor in fracture healing?

Accepted Answer

Immobilization

Answer

Good alignment

Answer

Organization of blood clot

Answer

Accurate reduction and 100% apposition of fractured fragments

Question 4

A patient operated for a forearm fracture under general anesthesia with a tourniquet was unable to move his fingers and had sensory loss over the entire hand postoperatively. What is the most common type of nerve injury in this scenario?

Accepted Answer

Neuropraxia

Answer

Axonotmesis

Answer

Neurotmesis

Answer

None of the above

Question 5

What is the X-ray diagnosis?

Accepted Answer

Supracondylar humerus fracture

Answer

Olecranon fracture

Answer

Humerus shaft fracture

Answer

Elbow dislocation

Question 6

A 25-year-old man presents with a blue right arm with absent radial pulse and painful passive finger extension following a supracondylar fracture of the humerus. What condition is he most likely suffering from?

Accepted Answer

Compartment syndrome

Answer

Sudeck's atrophy

Answer

Median nerve injury

Answer

Myositis ossificans

Question 7

A Tillaux fracture involves which part of the bone?

Accepted Answer

Lower end tibia

Answer

Upper end tibia

Answer

Lower end femur

Answer

Upper end femur

Question 8

What is a crescent fracture?

Accepted Answer

Fracture of the iliac crest

Answer

Fracture of the coccyx

Answer

Fracture of the calcaneum

Answer

Fracture of the Atlas

Question 9

Tinel's sign indicates which of the following?

Accepted Answer

Regeneration of nerves

Answer

Atrophy of nerves

Answer

Neuroma

Answer

Injury to nerve

Question 10

What is Neurapraxia?

Accepted Answer

Reversible physiological nerve conduction block

Answer

Complete division of nerve

Answer

Loss of conduction due to axonal interruption

Answer

Irreversible injury

Trauma — MCQs

Trauma — MCQs

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