A barium x-ray can detect problems with swallowing by determining what?

A barium x-ray is a specific imaging test used to evaluate the swallowing process and the function of the esophagus. When a patient swallows a barium contrast solution, it coats the lining of the throat and esophagus, allowing for a clear visual assessment of how effectively these muscles are functioning during the swallowing process. This test reveals the coordination and strength of the muscular contractions that occur when swallowing, which is critical for identifying any dysfunction that may be causing symptoms like dysphagia (difficulty swallowing).

In contrast, the other choices focus on aspects that, while related to swallowing, do not specifically address the primary function assessed by a barium swallow study. The movement of the tongue plays an important role in the swallowing process, but the primary function of the barium x-ray is to observe how well the throat and esophagus manage the passage of the substance. The speed at which food travels is relevant, but the examination focuses more on the function and coordination of the muscles involved. Lastly, the dilation of the esophagus is a factor that might be indirectly observed, but the core purpose of the barium x-ray pertains more to muscle function rather than mere dilation.