Surgery MCQs Q50

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ORTHOPEDICS • SPORTS MEDICINE

A 24-year-old rugby player develops sudden severe shoulder pain during a game. On examination, there is loss of normal shoulder contour (flattened deltoid contour / “squared-off” shoulder).

What is the most likely pathology?

A Acromioclavicular joint osteoarthritis

B Dislocation of shoulder

C Complete tear of triceps muscle

D Rupture of long head of biceps

E Fracture of surgical neck of humerus

The correct answer is Dislocation of shoulder.

Decoding the Stem

1

CLUE "Loss of normal shoulder contour / squared-off"

TRANSLATION Glenohumeral joint displacement → classic feature of anterior shoulder dislocation.

Detailed Explanation

✅ Correct Option (Shoulder Dislocation): Shoulder dislocations (95% anterior) are characterized by sudden trauma and a distinct "squared-off" appearance due to the humeral head no longer sitting under the acromion.

Clinical Key Points:

→ Mechanism: Usually forced abduction and external rotation (e.g., being tackled in rugby).

→ Deformity: The rounded deltoid becomes flat; the acromion becomes the most prominent point.

→ Position: Arm is typically held in slight abduction and external rotation.

❌ Why other options are incorrect:

→ AC Joint Osteoarthritis: A chronic condition causing localized superior pain, not acute deformity.

→ Biceps Rupture (Long Head): Causes the "Popeye" deformity in the mid-arm, but shoulder contour remains rounded.

→ Surgical Neck Fracture: While common in trauma, it usually presents with massive ecchymosis and pain, but not the specific "squared-off" void seen in dislocation.

🧠 High-Yield Pearls

✔ Most common dislocation: Shoulder (Glenohumeral joint).

✔ Nerve at Risk: Axillary nerve (test regimental badge area for sensation).

✔ Sign: "Squared shoulder" is pathognomonic in a trauma setting.

Integrated Clinical Questions

1. Most commonly injured nerve?

→ Axillary nerve.

2. Key clinical test for axillary nerve?

→ Sensation over the lateral shoulder (regimental badge area) and deltoid contraction.

3. Direction of most shoulder dislocations?

→ Anterior (>95%). Posterior is often associated with seizures or electric shocks.

4. Primary management approach?

→ Prompt closed reduction (under sedation/analgesia) followed by immobilization in a sling.

5. Pathognomonic visual deformity sign?

→ "Squared shoulder" appearance (loss of deltoid roundness).

⚡ Exam Pearls

• • Loss of shoulder contour = dislocation until proven otherwise.
• • Rugby/trauma + abduction injury = classic mechanism.
• • Always check Axillary nerve function before and after reduction.

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