Muscles surrounding the mouth

The muscles surrounding the mouth slit are divided into two groups. One group is represented by the circular muscle of the mouth, m. Orbicularis oris, the contraction of which narrows the mouth of the mouth. The other group includes muscles that are located radially with respect to the mouth slit; Their reduction leads to its expansion.

1. Circular muscle of the mouth , m. Orbicularis oris, is formed by circular muscular bundles located in the thickness of the lips. Muscle bundles are tightly fused to the skin. The superficial layers of this muscle take in their composition bundles of muscles that fit into the mouth slit. In the muscle, the marginal part, pars marginalis, and the labial part, pars labialis, are distinguished.

Function: Narrows the mouth and extends the lips forward.

Blood supply: aa. Labiales superior et inferior, mentalis.

2. Large zygomatic muscle , m. Zygomaticus major, begins from the external surface of the zygomatic bone. Part of the muscle bundles is an extension of m. Orbicularis oculi. Going down and medially, the zygomatic muscle is intertwined in the circular muscle of the mouth and the skin of the corner of the mouth.

Function: pulls the corner of the mouth up and out.

Blood supply: aa. Infraorbitalis, buccalis.

3. Small zygomatic muscle, m. Zygomaticus minor, starts from the anterior surface of the zygomatic bone.

Medial bundles of this muscle are intertwined with muscle beams m. Orbicularis oculi.

4. The muscle lifting the upper lip , m. Levator labii superioris, begins from the infraorbital margin, above the infraorbital foramen.

5. The muscle lifting the upper lip and the wing of the nose , m. Levator labii superioris alaeque nasi, is located next to the previous; Begins from the base of the frontal process of the upper jaw.

The last three muscles are sent down, somewhat convergent and form a quadrangular muscular plate, the bundles of which are woven into the skin of the upper lip, partly in m. Orbicularis oris, as well as in the skin of the wing of the nose.

Function: lifts the upper lip and tightens the wing of the nose.

Blood supply: aa. Infraorbitalis, labialis superior, buccalis.

6. Muscle lifting the corner of the mouth, m. Levator anguli oris, is located deeper than the previous one. It begins below the infraorbital foramen, from the canine fossa, and, going down, is weaved into the skin of the corner of the mouth and m. Orbicularis oris.

Function: pulls the corner of the mouth up and out.

Blood supply: aa. Infraorbitalis, buccalis.

7. Genital muscle, m. Buccinator ("trumpet muscle"), begins from the lower third of the anterior edge of the mandible, the wing-jaw joint (raphe pterygomandibularis), and also from the outer surface of the upper and lower jaws in the area of ​​the alveoli of large molars. Going forward, the bundles of the buccal muscle are weaved into the circular muscle of the mouth, as well as into the mucous membrane and skin of the corner of the mouth, upper and lower lips.

To the external surface of the muscle adjoins the fatty body of the cheek, corpus adiposum bucais, to the inner - the mucous membrane of the vestibule of the mouth. At the level of the anterior edge of the masticatory muscle, m. Masseter, middle parts of the buccal muscle perforate the excretory duct of the parotid gland, ductus parotideus.

Function: pulls the corner of the mouth to the side, with bilateral cuts stretches the mouth slit, presses the inner surface of the cheeks to the teeth.

Blood supply: a. Buccalis.

8. The muscle of laughter , m. Risorius, impermanent, is partly a continuation of the bundles of platysmatis; Part of the muscle beams originates from the chewing fascia and skin of the nasolabial fold area. Heading in the medial direction, the muscle bundles of it are woven into the skin of the corner of the mouth.

Function: pulls the corner of the mouth into the lateral side.

Blood supply: aa. Facialis, transvera faciei, buccalis.

9. The muscle that lowers the corner of the mouth , m. Depressor anguli oris, begins with a broad base from the anterior surface of the lower jaw, below the chin opening. Going up, the muscle narrows, reaches the corner of the mouth, where part of its beams interweaves in the skin of the corner of the mouth, and part - into the thickness of the upper lip and m. Levator anguli oris.

Function: pulls the corner of the mouth down and out.

Blood supply: aa. Labialis inferior, mentalis, submentalis.

10. Muscle lowering lower lip , m. Depressor labii inferioris, somewhat covered by the previous one. It starts from the front surface of the lower jaw, above the beginning of the previous muscle, anterior to the chin opening, is directed upwards and weaves into the skin of the lower lip and chin.

Medial muscle bundles near the lower lip are intertwined with the same beams of the same-named muscle of the opposite side.

Function: pulls the lower lip downwards.

Blood supply: aa. Labialis inferior, mentalis, submentalis.

11. The chin muscle, m. Mentalis, begins next to the previous one from the alveolar elevation of the incisors of the lower jaw, is directed downward and weaves into the skin of the chin.

Function: pulls the chin's skin up, pulls the lower lip.

Blood supply: aa. Labialis inferior, mentalis.

12. The transverse muscle of the chin, m. Transversus menti, a fickle little muscle that crosses the median line immediately under the chin; Is often an extension of m. Depressoris anguli oris.