Transthoracic lateral projections are primarily used to detect which of the following?

Transthoracic lateral projections are specifically designed to provide a clear view of the proximal humerus, making them particularly effective for identifying proximal humeral fractures. The orientation of this imaging technique allows for visualization of the humeral head and neck without superimposing the scapula, improving the chances of detecting fractures in that region.

In contrast, while other types of fractures can occur in the upper extremity, transthoracic lateral projections are not optimal for diagnosing distal humeral fractures, scapular fractures, or clavicular fractures. Each of these fractures may require different imaging techniques or views to achieve an accurate diagnosis. The focus on the proximal region of the humerus is why this type of projection is primarily associated with detecting fractures in that specific area, reinforcing the relevance of this imaging method in clinical practice.