The nasalis muscle is a
sphincter
A sphincter is a circular muscle that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning. Sphincters are found in many animals. There are over 60 types in the h ...
-like muscle of the
nose
A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes ...
. It has a transverse part and an alar part. It compresses the
nasal cartilages, and can "flare" the
nostrils
A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...
. Some people can use it to close the nostrils to prevent entry of
water
Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
when
underwater. It can be used to test the
facial nerve
The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste ...
(VII), which supplies it.
Structure
The nasalis muscle covers the
nasal cartilages of the lower surface of the
nose
A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes ...
. It consists of two parts, ''transverse'' and ''alar'':
* The ''transverse part'' (compressor naris muscle) arises from the
maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...
, above and lateral to the
incisive fossa
In the human mouth, the incisive foramen (also known as: "''anterior palatine foramen''", or "''nasopalatine foramen''") is the opening of the incisive canals on the hard palate immediately behind the incisor teeth. It gives passage to blood ves ...
. Its fibers proceed upward and medially, expanding into a thin
aponeurosis which is continuous on the bridge of the nose with that of the muscle of the opposite side, and with the aponeurosis of the
procerus muscle
The procerus muscle (or pyramidalis nasi) is a small pyramidal slip of muscle deep to the superior orbital nerve, artery and vein. ''Procerus'' is Latin, meaning tall or extended.
Structure
The procerus muscle arises by tendinous fibers from t ...
. It compresses the nostrils and may completely close them.
* The ''alar part'' (
dilator naris muscle
The dilator naris muscle (or alae nasi muscle) is a part of the nasalis muscle. It has an anterior and a posterior part. It has origins from the nasal notch of the maxilla and the major alar cartilage, and a single insertion near the margin of th ...
) arises from the
maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...
over the lateral incisor and inserts into the
greater alar cartilage
The major alar cartilage (greater alar cartilage) (lower lateral cartilage) is a thin, flexible plate, situated immediately below the lateral nasal cartilage, and bent upon itself in such a manner as to form the medial wall and lateral wall of th ...
. Its medial fibres tend to blend with the
depressor septi nasi muscle
The depressor septi nasi muscle (or depressor alae nasi muscle) is a muscle of the face. It connects the incisive fossa of the maxilla and the orbicularis oris muscle to the nasal septum of the nose. It draws the ala of the nose downwards, ...
, and has been described as part of that muscle.
Nerve supply
Like all the other muscles of facial expression, the nasalis muscle is supplied by the
facial nerve
The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste ...
(VII).
Function
The nasalis muscle compresses the
nasal cartilages. It may also "flare" the
nostrils
A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...
.
Some people can use it to close the nostrils to prevent entry of
water
Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
when
underwater.
Clinical significance
Cleft lip and cleft palate
The nasalis muscle is one of the key muscles not formed or inserted correctly with
cleft lip and cleft palate
A cleft lip contains an opening in the upper lip that may extend into the nose. The opening may be on one side, both sides, or in the middle. A cleft palate occurs when the palate (the roof of the mouth) contains an opening into the nose. The te ...
deformity.
The head of the transverse part needs to be identified during
reconstructive surgery
Reconstructive surgery is surgery performed to restore normal appearance and function to body parts malformed by a disease or medical condition.
Description
Reconstructive surgery is a term with training, clinical, and reimbursement implicat ...
so that it can be
surgically sutured (connected to) the
nasal septum
The nasal septum () separates the left and right airways of the nasal cavity, dividing the two nostrils.
It is depressed by the depressor septi nasi muscle.
Structure
The fleshy external end of the nasal septum is called the columella or co ...
.
The origin at the
maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...
may also be repositioned for better
symmetry.
Facial nerve testing
Due to it being superficial, the nasalis muscle can be used to test the
facial nerve
The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste ...
.
Specifically, it can be used to test the
zygomatic branches.
Additional images
File:Sobo 1909 260.png
File:Sobo 1909 262.png
File:Sobo 1909 264.png
File:Sobo 1909 266.png
File:Nasalis muscle animation small.gif, Position of nasalis muscle (shown in red).
File:Gray157.png, Left maxilla. Outer surface.
References
External links
Interactive diagram at ivy-rose.co.uk
{{Authority control
Muscles of the head and neck