Final answer:
A simple pneumothorax is typically caused by a nontraumatic cause and can be related to subtle connective tissue abnormalities, leading to a collapsed lung due to disruption of negative intrapleural pressure.
Step-by-step explanation:
A simple pneumothorax is commonly caused by a nontraumatic cause. Spontaneous pneumothorax is a type of simple pneumothorax that occurs without a clear cause such as blunt or penetrating trauma. Instead, it is believed to be related to subtle abnormalities in connective tissue. In cases of spontaneous pneumothorax, air enters the pleural space, and this can lead to a collapsed lung.
The precise mechanics involve the disruption of the negative intrapleural pressure that is vital for lung function. Normally, there is a balance of forces within the thorax, governed by the elasticity of the lung tissue, surface tension of alveolar fluid, and the outward force of the thoracic wall. A disruption in this balance can cause air to escape into the pleural space, creating a pneumothorax.