Share This Link

Carina. The carina is the point where the trachea divides into the right and left main bronchi. It plays no role in maintaining alveolar stability; instead, it functions primarily as a landmark and a sensitive area that triggers coughing when irritated.

Empyema. Empyema refers to the accumulation of pus in the pleural space due to infection. Rather than preventing collapse, it can actually impair lung expansion and gas exchange by restricting lung movement.

Thoracic cage. The thoracic cage protects the lungs and supports the respiratory system structurally, but it does not directly prevent alveolar collapse. Its role is mechanical, aiding in ventilation rather than maintaining alveolar patency.

Line the lung pleura. The alveolar sacs do not line the pleura; instead, the pleura are double-layered membranes that encase the lungs and line the thoracic cavity to reduce friction during breathing. The alveoli are located deep within the lung parenchyma, not along the pleural surface.

Warm and moisturize inhaled air. Warming and humidifying inspired air are functions of the upper respiratory tract, particularly the nasal passages and nasopharynx. The alveolar sacs are involved in gas exchange, not air conditioning.

Contain dead air that is not available for gas exchange. The alveolar sacs contain functional air that actively participates in gas exchange, not dead air. Dead space air is found in the conducting airways, such as the trachea and bronchi, where no exchange occurs.

Trachea. The trachea, or windpipe, is the airway that carries air to and from the lungs. It does not play a role in covering the larynx; instead, it remains open to facilitate airflow except when protected by the epiglottis during swallowing.

Turbinates. Turbinates are structures within the nasal cavity that warm, filter, and humidify inspired air. They are part of the upper respiratory tract but have no role in protecting the airway during swallowing.

Parietal pleura. The parietal pleura is a membrane lining the inside of the thoracic cavity. It serves to reduce friction during respiration, not to protect the airway or cover the larynx.

There is a prominent protrusion of the sternum. A protruding sternum is known as pectus carinatum, or pigeon chest, a congenital deformity unrelated to increased AP diameter. It involves abnormal chest wall structure rather than chronic pulmonary changes.

There is equal but diminished movement of the two sides of the chest. This finding suggests restricted chest wall movement, possibly due to neuromuscular weakness, pleural effusion, or severe respiratory fatigue, not an increased AP diameter.

The patient cannot fully expand the lungs because of kyphosis of the spine. Kyphosis causes a stooped posture and restricts chest expansion but does not result in an increased AP diameter. It leads to decreased lung expansion due to spinal curvature rather than barrel chest formation.