Glottis and epiglottis are situated in the pharynx, and help to protect the airway from aspiration during swallowing. Vocal cords that help to generate voice are also associated with glottis and epiglottis. Movement of arytenoids helps to open the glottis by moving upward and thus reduces the resistance to airflow. While swallowing, they move downward to close the vocal cord and epiglottis. This action prevents foods entering into the airway.
Glottis
Glottis is the narrowest part of the larynx and the opening into the airway. Vocal cords make lateral boarders of it. The intrinsic muscle of the larynx is responsible to dilate or contract the opening of the glottis. The size of the glottis is a factor in determining the individual’s voice. For example, an individual with a deep voice has a large glottis while an individual with a shrill voice has a small one. Glottic opening is a place between the vocal cords.
Epiglottis
Epiglottis is the superior boarder of the glottis opening. It is a leaf-shaped cartilaginous flap situated at the base of tongue. It prevents entering the food into the airway during swallowing. When swallowing, larynx muscles contract to cause upward movement of the glottis and downward movement of epiglottis. Epiglottis is attached to the tongue by glossoepiglottic ligament and to the hyoid bone by hypoepiglottic ligament. The anatomic space between the base of the tongue and epiglottis is known as the vallecula.
What is the difference between Glottis and Epiglottis?
• Glottis is the opening into the airway, whereas epiglottis is the superior boarder of the glottis.
• Unlike the epiglottis, the size of the glottis is responsible for the voice type.
• When swallowing starts, glottis moves upward and epiglottis moves downward.