MUSCLES OF FACIAL EXPRESSION

Editor's Notes

1. Forehead wrinkles are also called worry lines or expression lines. When a person makes the same facial expression repeatedly, temporary lines are produced in the face. Stress causes a person to frown quite a bit, which causes temporary forehead lines. Temporary lines can eventually turn into permanent lines. As the human body ages, our skin loses its elasticity and our muscles become weaker. This can lead to fine lines and wrinkles. Most wrinkles start out as fine lines, eventually turning into a wrinkle. A fine line can be hidden with light makeup. Wrinkles tend to be made worse with makeup, as the makeup sinks into the crevices of the face
2. The corneal reflex, also known as the blink reflex, is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), though could result from any peripheral stimulus. Stimulation should elicit both a direct and consensual response (response of the opposite eye). The reflex occurs at a rapid rate of 0.1 seconds. The purpose of this reflex is to protect the eyes from foreign bodies and bright lights (the latter known as the optical reflex).[1] The blink reflex also occurs when sounds greater than 40-60 dB are made.[2
3. Wrinkles=fine superficial lines,associated with repeated muscular contraction called mimetic lines pri’ cause-dermal elastosis & repeated facial & neck musculatar contraction
4. Parentheis lines-some individuals develops lines that arc around corners of mouth and usually ar extension of nasolabial folds They are often shallow,fine lines Marionette lines –formed mainly by depressor anguli oris muscle and platsyma run straight downwards from corners of mouth,make look unhappy Form as facial volume begins to deplete creases begin to form below mouth Inlection should be 1cm lateral to angle of mouth to avoid asymmetry Lipstick lines-that etchvertically from upper andlower lips -more prevalent on upper lips -while they are sometimes called=smokers lines,most individuals develop the lines are not smokers =are result of loss of volume that occurs with age -can contribute to lipstick bleeding,hence name=lipstick lines
5. Modiolus-fibro muscular node ,connecting insertions of facial muscles Serve as-hub, forms DIMPLE on cheek
6. The Orbicularis oris is not a simple sphincter muscle like the Orbicularis oculi; it consists of numerous strata of muscular fibers surrounding the orifice of the mouth but having different direction. It consists partly of fibers derived from the other facial muscles which are inserted into the lips, and partly of fibers proper to the lips. Of the former (other facial muscles) a considerable number are derived from the Buccinator and form the deeper stratum of the Orbicularis. Some of the Buccinator fibers—namely, those near the middle of the muscle—decussate at the angle of the mouth, those arising from the maxilla passing to the lower lip, and those from the mandible to the upper lip. The uppermost and lowermost fibers of the Buccinator pass across the lips from side to side without decussation. Superficial to this stratum is a second, formed on either side by the Caninus and Triangularis, which cross each other at the angle of the mouth; those from the Caninus passing to the lower lip, and those from the Triangularis to the upper lip, along which they run, to be inserted into the skin near the median line. In addition to these there are fibers from the Quadratus labii superioris, the Zygomaticus, and the Quadratus labii inferioris; these intermingle with the transverse fibers above described, and have principally an oblique direction. The proper fibers of the lips are oblique, and pass from the under surface of the skin to the mucous membrane, through the thickness of the lip. Finally there are fibers by which the muscle is connected with the maxillæ and the septum of the nose above and with the mandible below. In the upper lip these consist of two bands, lateral and medial, on either side of the middle line; the lateral band (m. incisivus labii superioris) arises from the alveolar border of the maxilla, opposite the lateral incisor tooth, and arching lateralward is continuous with the other muscles at the angle of the mouth; the medial band (m. nasolabialis) connects the upper lip to the back of the septum of the nose. The interval between the two medial bands corresponds with the depression, called the philtrum, seen on the lip beneath the septum of the nose. The additional fibers for the lower lip constitute a slip (m. incisivus labii inferioris) on either side of the middle line; this arises from the mandible, lateral to the Mentalis, and intermingles with the other muscles at the angle of the mouth
7. The Buccinator is a thin quadrilateral muscle, occupying the interval between the maxilla and the mandible at the side of the face. It arises from the outer surfaces of the alveolar processes of the maxilla and mandible, corresponding to the three molar teeth; and behind, from the anterior border of the pterygomandibular raphé which separates it from the Constrictor pharyngis superior. The fibers converge toward the angle of the mouth, where the central fibers intersect each other, those from below being continuous with the upper segment of the Orbicularis oris, and those from above with the lower segment; the upper and lower fibers are continued forward into the corresponding lip without decussation. Relations.—The Buccinator is covered by the buccopharyngeal fascia, and is in relation by itssuperficial surface, behind, with a large mass of fat, which separates it from the ramus of the mandible, the Masseter, and a small portion of the Temporalis; this fat has been named thesuctorial pad, because it is supposed to assist in the act of sucking. The parotid duct pierces the Buccinator opposite the second molar tooth of the maxilla. The deep surface is in relation with the buccal glands and mucous membrane of the mouth.
8. Caninus (Levator anguli oris) arises from the canine fossa, immediately below the infraorbital foramen; its fibers are inserted into the angle of the mouth, intermingling with those of the Zygomaticus, Triangularis, and Orbicularis oris.
9. Zygomaticus (Zygomaticus major) arises from the zygomatic bone, in front of the zygomaticotemporal suture, and descending obliquely with a medial inclination, is inserted into the angle of the mouth, where it blends with the fibers of the Caninus, Orbicularis oris, and Triangularis.
10. Quadratus labii inferioris (Depressor labii inferioris; Quadratus menti) is a small quadrilateral muscle. It arises from the oblique line of the mandible, between the symphysis and the mental foramen, and passes upward and medialward, to be inserted into the integument of the lower lip, its fibers blending with the Orbicularis oris, and with those of its fellow of the opposite side. At its origin it is continuous with the fibers of the Platysma. Much yellow fat is intermingled with the fibers of this muscle The Quadratus labii inferioris draws the lower lip directly downward and a little lateralward, as in the expression of irony
11. Triangularis (Depressor anguli oris) arises from the oblique line of the mandible, whence its fibers converge, to be inserted, by a narrow fasciculus, into the angle of the mouth. At its origin it is continuous with the Platysma, and at its insertion with the Orbicularis oris and Risorius; some of its fibers are directly continuous with those of the Caninus, and others are occasionally found crossing from the muscle of one side to that of the other; these latter fibers constitute the Transversus menti. action The Triangularis depresses the angle of the mouth, being the antagonist of the Caninus and Zygomaticus; acting with the Caninus, it will draw the angle of the mouth medialward
12. Risorius sardonicus-smile in tetenus .it s a smile like feature in agony due to pulling of muscles of the angle Risus Sardonicus(Smile of the joker)is one of classical signs of tetanus due to spastic effect of tetanus toxinpic Risorius arises in the fascia over the Masseter and, passing horizontally forward, superficial to the Platysma, is inserted into the skin at the angle of the mouth  It is a narrow bundle of fibers, broadest at its origin, but varies much in its size and form.   
13. Mentalis (Levator menti) is a small conical fasciculus, situated at the side of the frenulum of the lower lip. It arises from the incisive fossa of the mandible, and descends to beinserted into the integument of the chin. The Mentalis raises and protrudes the lower lip, and at the same time wrinkles the skin of the chin, expressing doubt or disdain.
14. Poor streched out sheets of platysma in neck which band & double over on themselves creating turkey gobbler neck deformity