Trauma Practice Questions

Q: Which mechanism of injury is most commonly associated with ankle joint injuries?

Inversion of the foot. **Explanation:** **1. Why Inversion is Correct:** Ankle sprains are among the most common musculoskeletal injuries, and approximately **85% of all ankle injuries** result from an **inversion mechanism**. This typically occurs when the foot is in a position of plantarflexion and the ankle rolls inward. The primary anatomical reason for this is the relative weakness of the lateral ligament complex compared to the medial (Deltoid) ligament. In an inversion injury, the **Anterior Talofibular Ligament (ATFL)** is the first and most common ligament to be torn, followed by the Calcaneofibular Ligament (CFL). **2. Analysis of Incorrect Options:** * **B. Eversion of the foot:** This mechanism is much less common because the **Deltoid ligament** on the medial side is extremely strong and thick. Eversion injuries often result in an avulsion fracture of the medial malleolus rather than a ligamentous tear. * **C. Internal rotation:** While internal rotation can occur during trauma, it is rarely the primary isolated mechanism for common ankle sprains. * **D. External rotation:** This mechanism is specifically associated with **syndesmotic injuries** (High Ankle Sprains) and certain types of Weber/Lauge-Hansen fractures (e.g., Supination-External Rotation), but it is statistically less frequent than simple inversion sprains. **3. Clinical Pearls for NEET-PG:** * **Most common ligament injured:** Anterior Talofibular Ligament (ATFL) – "Always Torn First." * **Ottawa Ankle Rules:** Used to determine if an X-ray is required (tenderness at the posterior edge of malleoli or inability to bear weight). * **Lauge-Hansen Classification:** The most common type of ankle fracture is the **Supination-External Rotation (SER)** injury. * **Treatment:** Most inversion sprains are managed conservatively with the **RICE** protocol (Rest, Ice, Compression, Elevation).

Q: What is the most common cause of neurological deficit in the upper limb?

Erb's palsy. **Explanation:** **Erb’s Palsy (Option B)** is the most common cause of neurological deficit in the upper limb, particularly in the pediatric population. It results from an injury to the **upper trunk of the brachial plexus (C5-C6)**, most frequently due to birth trauma (shoulder dystocia) or a forceful downward traction on the shoulder. This leads to the classic "Policeman’s tip" or "Waiter’s tip" deformity, characterized by an adducted, internally rotated arm with an extended elbow and pronated forearm. **Why other options are incorrect:** * **Polio (Option A):** While a significant cause of lower limb paralysis historically, it rarely presents as an isolated upper limb neurological deficit in modern clinical practice due to successful vaccination programs. * **C1-C2 Dislocation (Option C):** This is a life-threatening injury. Because it occurs above the phrenic nerve origin (C3-C5), it typically results in respiratory failure or sudden death rather than a localized upper limb deficit. * **Fracture dislocation of the cervical spine (Option D):** While these injuries cause neurological deficits, they usually result in **quadriplegia** (involving all four limbs) or specific spinal cord syndromes rather than an isolated upper limb palsy. **High-Yield Clinical Pearls for NEET-PG:** * **Site of Injury:** Erb’s point (junction of six nerves). * **Muscles Involved:** Deltoid, Biceps, Brachialis, and Brachioradialis. * **Reflexes:** Biceps and Supinator reflexes are lost; Moro reflex is asymmetrical. * **Klumpke’s Palsy:** Contrast this with C8-T1 injury, which causes a "claw hand" and potential Horner’s syndrome.

Q: In a supra condylar fracture of the humerus, which nerve is most commonly injured?

Median nerve. In a supracondylar fracture of the humerus (the most common pediatric elbow fracture), the mechanism usually involves a fall on an outstretched hand, leading to an **extension-type** injury. ### **Why the Median Nerve is Correct** In the extension-type fracture (95% of cases), the proximal humeral fragment is displaced anteriorly. This sharp bony spike pierces or stretches the structures lying immediately anterior to the distal humerus. The **Median nerve** (specifically the **Anterior Interosseous Nerve (AIN)** branch) is the most frequently injured nerve overall. The AIN is particularly vulnerable because it is fixed deeper and lacks a sensory component, often presenting as a motor deficit (inability to make the "OK" sign). ### **Why Other Options are Incorrect** * **Radial Nerve:** This is the second most common nerve injured in extension-type fractures (especially with posteromedial displacement). However, it is the *most* common nerve injured in humeral shaft fractures (Holstein-Lewis fracture). * **Ulnar Nerve:** This is most commonly injured in **flexion-type** supracondylar fractures (which are rare) or as an iatrogenic injury during medial percutaneous pinning. * **Axillary Nerve:** This nerve is associated with proximal humerus fractures or anterior shoulder dislocations, not distal humerus injuries. ### **NEET-PG High-Yield Pearls** * **Most common nerve injured (Overall/Extension type):** Median nerve (specifically AIN). * **Most common nerve injured (Flexion type):** Ulnar nerve. * **Most common vascular injury:** Brachial artery. * **Clinical Sign of AIN palsy:** Inability to flex the DIP joint of the index finger and IP joint of the thumb (Positive "Square" or "Pointing" sign; failed "OK" sign). * **Gartland Classification:** Used to grade the severity and displacement of these fractures.

Q: Seddon grading is used for what purpose?

Classification of nerve injuries. **Explanation:** **Seddon’s Classification** is the fundamental system used to grade **nerve injuries** based on the degree of damage to the nerve fiber and the connective tissue sheaths. It helps clinicians predict the prognosis and the necessity of surgical intervention. The classification consists of three stages: 1. **Neuropraxia:** The mildest form; a temporary physiological conduction block without anatomical disruption. Recovery is complete and rapid (weeks). 2. **Axonotmesis:** Disruption of the axon but the endoneurial sheath remains intact. Wallerian degeneration occurs distally, but recovery is possible through axonal regeneration (approx. 1mm/day). 3. **Neurotmesis:** Complete transection of the nerve and its connective tissue. Spontaneous recovery is impossible; surgical repair is required. **Analysis of Incorrect Options:** * **B. Grading of open fractures:** These are classified using the **Gustilo-Anderson classification**. * **C. Classification of Potts paraplegia:** This is typically described by the **Tuli’s classification** or categorized into Early-onset and Late-onset paraplegia. * **D. Grading of malignant bone tumors:** The most common system used is the **Enneking (MSTS) classification**. **High-Yield Clinical Pearls for NEET-PG:** * **Sunderland’s Classification:** An expansion of Seddon’s system into 5 degrees (1st degree = Neuropraxia; 5th degree = Neurotmesis). * **Wallerian Degeneration:** Begins 24–36 hours after injury in Axonotmesis and Neurotmesis. * **Tinel’s Sign:** A tingling sensation on percussion over a regenerating nerve; its distal progression is a positive prognostic sign in Axonotmesis.

Q: Avascular necrosis is a known complication of which of the following fractures?

Fracture of talus. **Explanation:** **Avascular Necrosis (AVN)** occurs when the blood supply to a bone is disrupted, leading to bone cell death. This is common in bones that are largely covered by articular cartilage and have a "retrograde" or vulnerable blood supply. **Why Talus is the Correct Answer:** The talus is a high-risk site for AVN because approximately 60% of its surface is covered by articular cartilage, leaving limited areas for nutrient vessels to enter. The primary blood supply comes from the **artery of the tarsal canal** (branch of the posterior tibial artery). Fractures of the **talar neck** frequently disrupt this blood supply. The risk of AVN is classified by the **Hawkins Classification**, where Type III and IV fractures have an AVN incidence of nearly 75–100%. **Why Other Options are Incorrect:** * **Medial condyle of femur:** While the femoral *head* is a classic site for AVN, the femoral *condyles* have a robust, multi-directional blood supply from the genicular anastomosis, making post-traumatic AVN rare. * **Olecranon fracture:** The olecranon has a rich periosteal blood supply and is not a "watershed" area; complications are usually related to non-union or hardware irritation. * **Radial head fracture:** Although it is intra-articular, the radial head has a relatively stable blood supply. While AVN can occur rarely, it is not a "classic" or high-yield complication compared to the talus. **NEET-PG High-Yield Pearls:** * **Common sites for AVN:** Femoral head (most common), Scaphoid (proximal pole), Talus (neck), and Humeral head. * **Hawkins Sign:** A subchondral radiolucency seen on X-ray 6–8 weeks post-fracture; its presence indicates intact vascularity (a good prognostic sign). * **Management:** Displaced talar neck fractures are surgical emergencies requiring urgent anatomical reduction to protect the remaining blood supply.

Q: Hoffman Tinel sign is seen in?

Nerve regeneration. **Explanation:** The **Hoffman-Tinel sign** (commonly referred to simply as the Tinel sign) is a clinical indicator of **nerve regeneration**. It is elicited by percussing or tapping over the course of a regenerating nerve. **Why it occurs:** When a peripheral nerve is injured and begins to heal, the regenerating axonal sprouts are "naked" (unmyelinated) and highly sensitive to mechanical stimulation. Tapping over these young axons triggers an electric-shock-like sensation or "pins and needles" (paresthesia) in the distal distribution of the nerve. As regeneration progresses, the point where the sign is elicited moves distally (at a rate of approximately 1 mm/day), allowing clinicians to track the progress of nerve recovery. **Analysis of Incorrect Options:** * **A & C (DVT and Pulmonary Embolism):** These are vascular/thromboembolic conditions. DVT is associated with **Homans' sign** (pain on dorsiflexion of the foot), not Tinel's sign. * **D (Upper Motor Neuron Lesion):** UMN lesions are characterized by spasticity, hyperreflexia, and the **Babinski sign**. The **Hoffmann sign** (flicking the nail of the middle finger causing flexion of the thumb/index finger) is seen in UMN lesions (cervical myelopathy), which is often confused with the Hoffman-Tinel sign due to the similar name. **High-Yield Clinical Pearls for NEET-PG:** * **Rate of Nerve Growth:** Approximately 1 mm per day or 1 inch per month. * **Order of Recovery:** Following a nerve injury, autonomic function returns first, followed by pain, touch, and finally motor function. * **Tinel Sign in Entrapment:** It is also used to diagnose nerve entrapment syndromes, most notably **Carpal Tunnel Syndrome** (tapping over the median nerve at the wrist). * **Prognostic Value:** A "distally advancing" Tinel sign is a positive prognostic indicator of recovery.

Q: An 18-year-old male presents with a history of trauma. An X-ray is shown below. What is the diagnosis?

Monteggia fracture. ***Monteggia fracture*** - Characterized by a **proximal ulna fracture** with **radial head dislocation**, which fits the typical pattern seen in trauma cases involving the forearm. - The **radiocapitellar line** on X-ray fails to pass through the center of the capitellum, confirming radial head dislocation - a pathognomonic sign. *Supra-Condylar Fracture* - Occurs in the **distal humerus** above the condyles, most commonly in children aged 5-8 years. - Would show **posterior angulation** of the distal fragment and potential **anterior humeral line** disruption on lateral X-ray. *Colles' Fracture* - Involves the **distal radius** with **dorsal displacement** and angulation, creating a "dinner fork" deformity. - Typically occurs in **elderly patients** following a fall on an outstretched hand, not involving ulna or radial head. *Galeazzi fracture* - Features a **distal radius fracture** with **distal radioulnar joint (DRUJ) dislocation**, opposite to Monteggia pattern. - Mnemonic: **"GRU"** - Galeazzi = Radius fracture + Ulnar dislocation; **"MoRU"** - Monteggia = Radius dislocation + Ulnar fracture.

Q: A 55-year-old woman presents with a traumatic injury to her right thigh. Which of the following findings is most sensitive for the diagnosis of compartment syndrome?

Pain. **Explanation:** Compartment syndrome is a surgical emergency characterized by increased pressure within a fibro-osseous space, leading to compromised tissue perfusion. **Why Pain is the Correct Answer:** **Pain out of proportion to the injury** and **pain on passive stretching** of the muscles in the affected compartment are the **earliest and most sensitive** clinical findings. In a conscious patient, this is the most reliable indicator for early diagnosis. As pressure rises, it first affects the sensory nerves and small vessels, triggering intense ischemic pain before other clinical signs manifest. **Analysis of Incorrect Options:** * **Paresthesias (B):** This indicates early nerve ischemia. While it is an important sign, it typically occurs *after* the onset of severe pain, making it less sensitive for the very earliest diagnosis. * **Pulselessness (A) and Pallor (D):** These are **late and ominous signs.** Because the intracompartmental pressure required to cause compartment syndrome is usually lower than the systolic arterial pressure, distal pulses often remain palpable until irreversible muscle necrosis has occurred. Relying on these signs for diagnosis often leads to missed opportunities for limb salvage. **High-Yield Clinical Pearls for NEET-PG:** * **The 6 P’s:** Pain, Poikilothermia, Pallor, Paresthesia, Pulselessness, and Paralysis. * **Gold Standard Diagnosis:** Measurement of intracompartmental pressure (using a Stryker device). * **Delta Pressure:** (Diastolic BP – Intracompartmental Pressure). A Delta pressure **< 30 mmHg** is diagnostic and an indication for fasciotomy. * **Management:** Immediate **emergency fasciotomy** (leaving the wound open) to decompress all involved compartments.

Question 1

Which mechanism of injury is most commonly associated with ankle joint injuries?

Accepted Answer

Inversion of the foot

Answer

Eversion of the foot

Answer

Internal rotation of the foot

Answer

External rotation of the foot

Question 2

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

Accepted Answer

Supracondylar fracture of humerus

Answer

Fracture of lower half of tibia

Answer

Fracture of neck of femur

Answer

Fracture of scaphoid

Question 3

What is the most common cause of neurological deficit in the upper limb?

Accepted Answer

Erb's palsy

Answer

Polio

Answer

C1-C2 dislocation

Answer

Fracture dislocation of the cervical spine

Question 4

In a supra condylar fracture of the humerus, which nerve is most commonly injured?

Accepted Answer

Median nerve

Answer

Radial nerve

Answer

Ulnar nerve

Answer

Axillary nerve

Question 5

Seddon grading is used for what purpose?

Accepted Answer

Classification of nerve injuries

Answer

Grading of open fractures

Answer

Classification of Potts paraplegia

Answer

Grading of severity of malignant bone tumors

Question 6

Avascular necrosis is a known complication of which of the following fractures?

Accepted Answer

Fracture of talus

Answer

Fracture of medial condyle of femur

Answer

Olecranon fracture

Answer

Radial head fracture

Question 7

Hoffman Tinel sign is seen in?

Accepted Answer

Nerve regeneration

Answer

Deep Vein Thrombosis

Answer

Pulmonary embolism

Answer

Upper motor neuron lesion

Question 8

An 18-year-old male presents with a history of trauma. An X-ray is shown below. What is the diagnosis?

Accepted Answer

Monteggia fracture

Answer

Supra-Condylar Fracture

Answer

Colles' Fracture

Answer

Galeazzi fracture

Question 9

A 55-year-old woman presents with a traumatic injury to her right thigh. Which of the following findings is most sensitive for the diagnosis of compartment syndrome?

Accepted Answer

Pain

Answer

Pulselessness

Answer

Paresthesias

Answer

Pallor

Question 10

In lower-third fractures of the shaft of the femur, which displacement does the proximal fragment undergo?

Accepted Answer

Abduction

Answer

Adduction

Answer

Flexion

Answer

Extension

Trauma — MCQs

Trauma — MCQs

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