Examkin

Question

Difficulty: HardOrthopedic Surgery

Match each patient's clinical presentation of an orthopedic injury with the most likely associated neurovascular complication or mandatory physical examination finding.

  • A 24-year-old man with a deformed arm after a direct blow; radiographs show a transverse fracture at the middle third of the humerus.Assessment reveals an inability to extend the wrist and fingers against resistance.
  • A 19-year-old man holding his right arm in slight abduction and external rotation after a fall; the acromion is prominent.Assessment reveals decreased pinprick sensation over the lateral aspect of the shoulder.
  • A 32-year-old woman in a high-speed collision presenting with a shortened, internally rotated, and adducted right lower extremity.Assessment reveals weakness of ankle dorsiflexion and great toe extension.
  • A 28-year-old pedestrian struck by a car presenting with gross multidirectional instability of the tibiofemoral joint.Assessment reveals diminished distal pulses requiring urgent ankle-brachial index measurement.
  • A 7-year-old boy with a swollen, painful elbow after a fall; radiographs show an extension-type fracture just above the condyles.Assessment reveals an inability to flex the distal interphalangeal joint of the index finger and interphalangeal joint of the thumb.

Answer

Midshaft humerus fracture matches with inability to extend wrist. Anterior shoulder dislocation matches with decreased lateral shoulder sensation. Posterior hip dislocation matches with weakness of ankle dorsiflexion. Knee dislocation matches with diminished distal pulses requiring ABI. Pediatric supracondylar fracture matches with inability to flex distal index finger and thumb.
Correct matching relies on understanding the anatomical relationships between bones, joints, and adjacent neurovascular structures. Midshaft humerus fractures threaten the radial nerve; anterior shoulder dislocations threaten the axillary nerve; posterior hip dislocations threaten the sciatic nerve; knee dislocations carry a high risk of popliteal artery injury; and pediatric supracondylar humerus fractures commonly injure the anterior interosseous branch of the median nerve.

Step-by-Step Solution

1
Analyze the presentation of the midshaft humerus fracture.
Identified risk to the radial nerve.
The radial nerve courses through the spiral groove of the humerus, making it highly susceptible to injury in midshaft fractures, leading to impaired wrist and finger extension.
2
Analyze the presentation of the anterior shoulder dislocation.
Identified risk to the axillary nerve.
The axillary nerve wraps around the surgical neck of the humerus and can be stretched during an anterior dislocation, causing loss of sensation over the lateral deltoid.
3
Analyze the presentation of the shortened, internally rotated, and adducted lower extremity.
Diagnosed as a posterior hip dislocation, identifying risk to the sciatic nerve.
The sciatic nerve runs directly posterior to the hip joint. A posterior dislocation can compress it, most commonly affecting the common peroneal division and causing foot drop.
4
Analyze the presentation of the tibiofemoral joint instability.
Diagnosed as a knee dislocation, identifying critical risk to the popliteal artery.
The popliteal artery is rigidly tethered proximally and distally to the knee joint, making it highly vulnerable to tethering and intimal tearing during a gross dislocation.
5
Analyze the presentation of the pediatric extension-type supracondylar humerus fracture.
Identified risk to the anterior interosseous nerve.
The anterior interosseous nerve (a branch of the median nerve) is the most commonly injured nerve in extension-type supracondylar fractures, leading to weakness of the flexor pollicis longus and flexor digitorum profundus (loss of the 'OK' sign).

Key Concept

Neurovascular complications of specific orthopedic injuries
Rate this question

Topics

Orthopedic Surgery

More questions from this topic