The depressor septi nasi is one of the three separate nasal muscles. The muscle emerges from out of the upper jaw’s incisive fossa, which is a bone opening in the front-center of the roof of the mouth. It inserts into both the septum (the bone and cartilage that separates the nose’s two airways) and the ala's posterior side. The ala of nose is the section on the outside of the nose that juts out to establish a rounded protuberance near the nostril.
This facial muscle is situated between the lip's muscular structure and the mucous membrane. The facial nerves' buccal branches supply nerves to the muscle.
The depressor septi nasi is used to constrict the nostrils. It also works with the nasalis muscles' dilator in order to flare the nostrils wider when a person breathes in deeply through their nose. It is located near the dilator naris posterior and the dilator naris anterior, both of which are muscles.