Muscles of Form and Expression (Test 1) Flashcards
The musculature system
covers, shapes, and supports the skeleton.
The restorative artist is interested in muscles that influence:
surface forms and expressions.
Relationship with the surface
bones, muscles, fascia & glands, and integument (skin)
____________ muscles will affect __________ form.
superficial, surface
Contracting muscles draw the skin with it. Resulting surface formations are:
- prominences 2. hollows 3. folds 4. furrows
Loss of muscular tone results in:
- sagging of the tissue 2. an effect on the form of the head and features.
Gravitational pull
- when standing the pull is inferior 2. when lying horizontal the pull is lateral & posterior 3. there may be complaints of the old looking “too young”
Movement of muscles
- for every muscle pulling in one direction, another is there to return it to position.
Points of attachment (movement of muscles)
- origin - end of the muscle attached to a fixed point (bone, cartilage). 2. insertion - end of the muscle attached to a movable part or skin.
Furrows
(wrinkles) - cross the direction of muscles at right angles. EX: forehead muscles are vertical so wrinkles are horizontal.
Construction of muscles
over 500 muscles in the human body, and account for 40-50% of body weight.
Length and number of fibers (construction of muscles)
muscles whose fibers are long and few in number have little strength. Muscles whose fibers are short and many in number are powerful.
Muscle types: Quadrilateral
fibers are parallel and run directly from origin to insertion.
Muscle types: sphincter
fibers surround a natural orifice
Muscle types: Fan-shaped
fibers which converge to a narrow insertion. EX: temporalis muscle.
Muscle types: double bellied
consist of two fleshy portions which are separated by a tendon or an aponeurosis (a flattened, ribbon-shaped tendon).
Muscles of the cranium - occipitofrontalis - epicranius
Covers the top and side of the skull from the occipital bone to the eyebrows. It is composed of 2 broad bellies: occipital belly and frontal belly which is continuous with the procerus muscle (over the top of the nose). The two broad bellies are connected by a large intermediate aponeurosis, the galea aponeurotica. The inferior furrows of the forehead are usually deeper.
Muscles of mastication: Temporalis (2)
a broad fan shaped muscle. Strongest of the chewing muscles. The fibers converge as they descend and end in a strong tendon which inserts in the coronoid process, a part of the mandible.
Muscles of mastication: Masseter (2)
it’s name means “to chew”. Raises the lower jaw. Thick quadrilateral muscle. Origin: anterior 2/3 of zygomatic arch, and lower border of the cheekbone. Insertion: lower half of the jaw and angle of the ramus.
Muscles of the face (general description)
are cutaneous muscles. They lie within layers of superficial fascia. Are shorter and thinner (more active and responsive).
Muscles of the eyelids: Obicularis Oculi (2)
sphincter muscle. Crow’s feet (layman’s term) - Optic facial sulci.
Muscles of the eyelids: Corrugator (2)
Frowning muscle, draws eyebrows downward and medial.
Muscles of the eyelids: Levator palpebrae superioris (2)
Palpebrae = eyelid. Raises the upper eyelid. May cut when unable to close eyelid.
Muscles of the nose: Procerus (1)
Fibers merge with the frontalis muscle. draws the medial ends of the eyebrows down. (lower muscles affect the nostrils).
Muscles of the mouth: obicularis oris (1)
this large sphincter muscle encircles the mouth, 10 pairs of muscles insert into the sphincter.
Quadratus Labii Superioris
quadrilateral muscle. Originates along the entire lower margin of the eyesocket. Runs downward to upper lip. Composed of 3 heads (levator labii superioris alaeque nasi, levator labii superioris, and zygomaticus minor).
Heads of Quadratus Labii Superioris: Levator labii superioris alaeque nasi (2)
“common elevator” of the upper lip and wing of the nose.
Heads of Quadratus Labii Superioris: levator labii superioris (1)
raises the upper lip
Heads of Quadratus Labii Superioris: zygomatic minor (2)
from the anterior part of the zygomatic bone it moves obliquely downward and medialward inserting in the upper lip at the angle of the mouth.
Contraction of the Quadratus Labii Superioris
together with the levator anguli oris, lends to the increasing development of the fold of skin at the anterior margin of the cheek known as the nasolabial fold.
Levator anguli oris (2)
elevator of the angle of the mouth. Located in the region of the canine tooth (originates from the canine fossa and inserts into the angle of the mouth). Contributes to the formation of the nasolabial fold and angulus oris eminence (natural facial markings).
Zygomaticus major (2)
descends obliquely from the posterior portion of the cheekbone to the angle of the mouth. “Laughing muscle” - draws the angles of the mouth backward and upward. Helps create the the prominence of the nasolabial fold. Point of insertion contributes to the fullness of the angulus oris eminence. Change of planes from the front to the side of the face.
Buccinator (2)
“Trumpeter’s muscle”. Thin quadrilateral muscle. Principal cheek muscle. Creates the lateral wall of the mouth.