The zygomaticus minor muscle is a

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

of facial expression. It originates from the

zygomatic bone In the human skull, the zygomatic bone (from ), also called cheekbone or malar bone, is a paired irregular bone, situated at the upper and lateral part of the face and forming part of the lateral wall and floor of the orbit, of the temporal fos ...

, lateral to the rest of the levator labii superioris muscle, and inserts into the outer part of the upper lip. It draws the

upper lip The lips are a horizontal pair of soft appendages attached to the jaws and are the most visible part of the mouth of many animals, including humans. Mammal lips are soft, movable and serve to facilitate the ingestion of food (e.g. sucklin ...

backward, upward, and outward and is used in smiling. It is innervated 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 ta ...

(VII).

Structure

The zygomaticus minor muscle passes inferomedially from its origin to its insertion at an angle of approximately 30°. It has a mean width of around 0.5 cm.

Origin

It originates from the lateral aspect of just posterior to the zygomaticomaxillary suture.

Insertion

It inserts into the muscular tissue of the upper lip, blending distally with

levator labii superioris The levator labii superioris (: ''levatores labii superioris'', also called quadratus labii superioris, : ''quadrati labii superioris'') is a muscle of the human body used in facial expression. It is a broad sheet, the origin of which extends fro ...

muscle.

Innervation

The zygomaticus minor muscle receives motor innervation from the zygomatic branches and buccal branches of the facial nerve (CN VII).

Relations

The zygomaticus minor lies lateral to the rest of levator labii superioris muscle, and medial to its stronger synergist

zygomaticus major muscle The zygomaticus major muscle is a muscle of the face. It arises from either zygomatic arch (cheekbone); it inserts at the corner of the mouth. It is innervated by branches of the facial nerve (cranial nerve VII). It is a muscle of facial expres ...

Variation

The zygomaticus minor muscle may have either a straight or a curved course along its length. It may attach to both the

and the lateral alar region. It may be underdeveloped in some people, with its role taken over by nearby synergists. These synergists rarely change shape or position, but any difference in smile is usually imperceptible.

Function

The zygomaticus minor muscle draws the

up, back, and out, such as during smiling.

History

The zygomaticus minor muscle is sometimes referred to as the "zygomatic head" of the

muscle.

Additional images

File:Zygomaticus minor muscle animation small.gif, Zygomaticus minor muscle (shown in red).

References

External links

PTCentral
{{Authority control Facial muscles