Which neuromuscular function is described as most important during the oral transit phase?

• A. Chewing
• B. Lip closure
• C. Tongue motion
• D. Jaw opening

Answer: (C)

Tongue motion is what actually carries the bolus through the oral cavity during the oral transit phase. After the bolus is formed and sealed inside the mouth, the tongue elevates, presses against the palate, and then moves backward in a coordinated, wave-like propulsion. This posterior movement is the main driver that pushes the material toward the oropharynx and sets up the swallow trigger at the back of the mouth.

Other functions around this phase support propulsion but don’t move the bolus forward to the same extent. Lip closure helps keep the bolus contained and prevent spillage, while chewing shapes and breaks down solids into a cohesive mass. Jaw opening and closing aids in managing the bolus but aren’t the primary mechanism pushing it back. When tongue motion is strong and well-timed, transit is smooth and efficient; when tongue control is poor, residue and delays can occur.