Anatomy Thorax Abdomen · Year 1 · from Anatomy Thorax Abdomen
Case 1: Spontaneous Pneumothorax
Clinical Presentation
A 22-year-old tall, thin male presents to the emergency department with sudden onset of right-sided chest pain and shortness of breath that began 2 hours ago while he was playing basketball. He reports the pain is sharp, pleuritic in nature, and worsens with deep inspiration. He denies any recent trauma, cough, or fever. He has a 3-pack-year smoking history. On examination, he is mildly tachypneic with a respiratory rate of 22 breaths per minute and oxygen saturation of 94% on room air. Examination of the right hemithorax reveals decreased breath sounds, hyperresonance to percussion, and decreased tactile fremitus compared to the left side.
Chest radiograph demonstrates absence of lung markings in the right upper hemithorax with a visible visceral pleural line separated from the chest wall. The pneumothorax is measured at approximately 3 cm from the chest wall at the level of the hilum, indicating a large pneumothorax. There is no mediastinal shift, indicating this is not a tension pneumothorax. The patient undergoes chest tube placement in the right fifth intercostal space at the anterior axillary line with subsequent lung re-expansion confirmed on follow-up imaging.
Radiographic Findings
Image: Chest radiograph demonstrating a right-sided pneumothorax. Note the visible pleural line (visceral pleura) separated from the chest wall with absence of lung markings peripheral to this line. Source: Wikimedia Commons, Public Domain.
Key Anatomical Points
- The pleural cavity is normally a potential space containing only a thin layer of serous fluid
- Negative intrapleural pressure (-5 cm H2O) normally keeps the lung expanded against the chest wall
- When air enters the pleural space, this negative pressure is lost and the lung collapses away from the chest wall
- Primary spontaneous pneumothorax typically occurs in tall, thin young males due to rupture of apical subpleural blebs
- The visceral pleura is insensitive to pain (autonomic innervation), but the parietal pleura is highly sensitive (somatic innervation from intercostal nerves), explaining the sharp, localized chest pain
Key Learning Points
- The pleural cavity extends higher than the lung margin, with the cervical pleura rising 2-3 cm above the clavicle
- Chest tube insertion follows the "safe triangle" bounded by the anterior border of latissimus dorsi, lateral border of pectoralis major, and a line at the level of the nipple
- The tube must pass immediately above the rib to avoid the intercostal neurovascular bundle running in the costal groove along the inferior border of each rib