What describes the superficial layer of the lamina propria as per Hirano's model?

The superficial layer of the lamina propria, according to Hirano's model, is characterized by fluid-filled and loosely structured fibers. This layer is also known as the Reinkeme layer and plays a crucial role in vocal fold vibration. The loose structure allows for greater mobility of the overlying epithelium during phonation, enabling the vocal folds to produce sound effectively. The presence of fluid within this layer contributes to its pliability, allowing the vocal folds to oscillate freely and create sound waves through their vibrations.

This fluid-filled characteristic is essential for enabling the vocal folds to maintain a balanced tension and elasticity during vibration, which is critical for various pitch and volume changes in vocal production.