Several muscles control the movement of the nostrils, including the nasalis, procerus, and depressor septi. The nasalis muscle acts as a sphincter-like muscle, compressing the nasal cartilages and "flaring" the nostrils. The procerus muscle, located above the bridge of the nose, helps wrinkle the forehead and pull the eyebrows down. The depressor septi nasi muscle pulls the tip of the nose downwards and also plays a role in opening the nostrils. Another muscle, the levator labii superioris alaeque nasi, while associated with the oral group, also functions to open the nostrils and elevate the upper lip. These muscles are innervated by the facial nerve (CN VII).
The nasal muscles play a critical role in various functions, including:
- Breathing: By controlling the airflow through the nostrils.
- Smell: By regulating the flow of air over the olfactory receptors.
- Facial expressions: By contributing to various expressions, such as frowning or sniffing.
- Speech: By influencing the resonance of the voice.
It's important to note that these muscles work together to control the nostrils, and their function can vary depending on the specific action.
