Which diagnostic test measures muscle function using a pressure-sensitive tube?

The correct choice is the test that accurately measures muscle function by using a pressure-sensitive tube. This test is known as manometry, which involves inserting a pressure-sensitive tube into the esophagus or other hollow organs to assess the function and coordination of muscles, particularly those involved in swallowing and other gastrointestinal functions.

Manometry is especially crucial in evaluating conditions like dysphagia (difficulty swallowing) or gastroesophageal reflux disease (GERD), providing valuable insights into muscle strength and peristaltic activity. The use of a pressure-sensitive tube allows for precise measurement of pressure along the muscle, yielding important diagnostic information.

Other tests mentioned do not fit this definition. For instance, electromyography (EMG) measures electrical activity in muscles but does not utilize a pressure-sensitive tube. Gastroscopy involves a visual examination of the gastrointestinal tract using a flexible tube with a camera, and ultrasound employs sound waves to visualize structures within the body, neither of which involves measuring muscle function through pressure assessment.