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Difficulty: HardOrthopedic Surgery

Match each clinical presentation of an acute orthopedic injury to its most likely associated neurological examination deficit.

  • A 42-year-old male falls forcefully on his shoulder; examination reveals a flattened anterior shoulder contour and an externally rotated, slightly abducted arm.Weakness in shoulder abduction beyond 15 degrees and decreased sensation over the lateral deltoid region.
  • A 28-year-old male involved in a motor vehicle collision presents with severe hip pain; his right lower extremity is shortened, internally rotated, and adducted.Weakness in ankle dorsiflexion and plantar flexion, with decreased sensation over the posterolateral leg and foot.
  • A 35-year-old female falls on an outstretched hand, sustaining a supracondylar humerus fracture; radiographs show anteromedial displacement of the proximal fracture fragment.Weakness in thumb opposition, impaired wrist flexion, and decreased sensation over the palmar surface of the lateral three-and-a-half digits.
  • A 22-year-old male sustains a direct blow to the lateral aspect of the leg, resulting in a displaced fracture of the fibular neck.Inability to dorsiflex the ankle or evert the foot, with decreased sensation over the anterolateral leg and dorsum of the foot.
  • A 31-year-old male sustains a transverse midshaft humerus fracture after being struck with a heavy object.Inability to extend the wrist and digits, with decreased sensation over the posterior forearm and dorsal web space of the hand.

Answer

Anterior shoulder dislocations correspond to axillary nerve deficits; posterior hip dislocations to sciatic nerve deficits; anteromedially displaced supracondylar fractures to median nerve deficits; fibular neck fractures to common peroneal nerve deficits; and midshaft humerus fractures to radial nerve deficits.
Each correct pair accurately links a classic orthopedic injury mechanism to the specific peripheral nerve that is anatomically most vulnerable at that site, and subsequently matches that nerve to its exact motor and sensory distribution.

Step-by-Step Solution

1
Identify the specific fracture or dislocation pattern presented in each clinical vignette.
The vignettes describe anterior shoulder dislocation, posterior hip dislocation, supracondylar humerus fracture, fibular neck fracture, and midshaft humerus fracture.
Recognizing the exact anatomical location and mechanism of the injury is required to determine the structures at risk.
2
Determine the neurovascular structure that runs in closest proximity to the injured bone or joint.
The associated nerves are the axillary nerve, sciatic nerve, median nerve, common peroneal nerve, and radial nerve, respectively.
Acute orthopedic injuries predictably threaten adjacent peripheral nerves due to traction, compression, or direct laceration.
3
Correlate the injured peripheral nerve with its expected motor and sensory examination findings.
Matched the anatomical nerve injury to specific physical exam deficits (e.g., matching the common peroneal nerve to foot drop and dorsal sensory loss).
Each peripheral nerve has a distinct innervation pattern that dictates the resulting clinical neurological deficit.

Key Concept

Predictable peripheral nerve injuries associated with specific acute orthopedic fractures and joint dislocations.
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Topics

Orthopedic Surgery

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