The nasalis muscle is a
sphincter-like muscle of the
nose. It has a transverse part and an alar part. It compresses the
nasal cartilages The nasal cartilages are structures within the nose that provide form and support to the nasal cavity. The nasal cartilages are made up of a flexible material called hyaline cartilage (packed collagen) in the distal portion of the nose. There are fi ...
, and can "flare" the
nostrils. Some people can use it to close the nostrils to prevent entry of
water when
underwater. It can be used to test the
facial nerve (VII), which supplies it.
Structure
The nasalis muscle covers the
nasal cartilages The nasal cartilages are structures within the nose that provide form and support to the nasal cavity. The nasal cartilages are made up of a flexible material called hyaline cartilage (packed collagen) in the distal portion of the nose. There are fi ...
of the lower surface of the
nose. It consists of two parts, ''transverse'' and ''alar'':
* The ''transverse part'' (compressor naris muscle) arises from the
maxilla, above and lateral to the
incisive fossa. Its fibers proceed upward and medially, expanding into a thin
aponeurosis
An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...
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. It compresses the nostrils and may completely close them.
* The ''alar part'' (
dilator naris muscle) arises from the
maxilla over the lateral incisor and inserts into the
greater alar cartilage. Its medial fibres tend to blend with the
depressor septi nasi muscle, 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 (VII).
Function
The nasalis muscle compresses the
nasal cartilages The nasal cartilages are structures within the nose that provide form and support to the nasal cavity. The nasal cartilages are made up of a flexible material called hyaline cartilage (packed collagen) in the distal portion of the nose. There are fi ...
. It may also "flare" the
nostrils.
Some people can use it to close the nostrils to prevent entry of
water 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 deformity.
The head of the transverse part needs to be identified during
reconstructive surgery so that it can be
surgically sutured (connected to) the
nasal septum.
The origin at the
maxilla may also be repositioned for better
symmetry
Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definit ...
.
Facial nerve testing
Due to it being superficial, the nasalis muscle can be used to test the
facial nerve.
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