cervical muscles and muscles of facial expressions

Sternocleidomastoid Muscle (SCM)

One of the largest and most superficial cervical muscles paired Thick serves as a primary muscular landmark of the neck during an extraoral examination of a patient divides the neck region into anterior and posterior cervical triangles This helps define the location of structures such as the lymph nodes for the head and neck

Clinical Note: Incompetent Lips and Lip Seal Failure

Orbicular Oris Muscle Incompetent lips or failure to provide a lip seal can affect the position of the maxillary incisors, canines, and the premolars Also present can be dehydration of anterior teeth at incisal edges due to open mouth resting posture of the lips

Zygomaticus Major Muscle: Origin and Insertion

The muscle originates from the zygomatic bone, lateral to the zygomaticus minor passes anteriorly and inferiorly to insert into the skin at the ipsilateral labial commissure, in and around the obicularis oris

Depressor Labii Inferioris Muscle: Origin and Insertion

The muscle originates from the inferior border of the mandible passes superiorly to then insert into the skin of the lower lip

Epicranial Muscle: Action

both bellies of the epicranial muscle raise the eyebrows and scalp - surprise two bellies can act independently of each other during certain facial expressions

nasalis

Nasal Muscle largest and best developed of the group active when the nares are flared

The three muscles associated with the nasal region:

Nasalis Procerus depressor septi nasi

Levator Labii Superioris Muscle

broad, flat muscle of facial expression in the oral region

Levator Anguli Oris Muscle: Action

elevates the labial commissure when a person smiles

Zygomaticus Major Muscle: Action

elevates the labial commissure of the upper lip and pulls it laterally when a person smiles

Zygomaticus Minor Muscle: Action

elevates the upper lip assists in smiling

Levator Labii Superioris Alaeque Nasi Muscle: Action

elevates the upper lip and ala of the nose dilates each nares, as in a sneering expression

Trapezius Muscle: Innervation

eleventh cranial or accessory nerve third and fourth cervical nerves

Sternocleidomastoid Muscle: Innervation

eleventh cranial or accessory nerve.

orbicularis oculi muscle

encircles the orbit important functions in protecting and moistening the eye, as well as in facial expression loss of its use can possibly damage the eye(s) due to the subsequent dryness

Facial paralysis can occur with a

stroke (or cerebrovascular accident), Bell palsy, or possibly with parotid salivary gland cancer because the seventh cranial or facial nerve travels through the gland.

Corrugator Supercilii Muscle

orbital region, deep to the superior part of the orbicularis oculi muscle

Trapezius Muscle

superficial to both the lateral and posterior surfaces of the neck broad, flat, triangular

The epicranial aponeurosis is at the most ____ part of the skull

superior

Trapezius Muscle: Origin and Insertion

originates from the external surface of the occipital bone and the posterior midline of the cervical and thoracic regions inserts on the lateral third of the clavicle and parts of the scapula

Levator Labii Superioris Muscle: Origin and Insertion

originates from the infraorbital rim of the maxilla passes inferiorly to insert into the skin of the upper lip

Orbicularis Oculi Muscle: Origin and Insertion

originates on the: -orbital rim -nasal process of the frontal bone -frontal process of the maxilla most fibers insert into the skin at the lateral canthus some inner fibers completely encircle the orbit

Sternocleidomastoid Muscle (SCM) origin and insertion

originates-the medial part of the clavicle and the sternum's superior and lateral surfaces. inserts-on the mastoid process of the temporal bone as well as by a thin aponeurosis or layer of flat broad tendons into the lateral half of the superior nuchal line of the occipital bone This insertion is just posterior and inferior to the external acoustic

Muscles of Facial Expression

paired muscles within the superficial fascia of the facial tissue Use of these muscles is noted during an extraoral examination, assuring the function of the nerves to these muscles

Zygomaticus Major Muscle

A muscle of facial expression in the oral region is the zygomaticus major muscle, that is located lateral to the zyomaticus minor muscle

Epicranial muscle

AKA epicranius muscle of facial expression in the scalp region this muscle and its tendon are one of the layers that form the scalp

Muscles of Facial Expression: Innervation

All are innervated by the seventh cranial or facial nerve -each nerve serving one side of the face Branches designated according to location across the face

Muscles of Facial Expression: Origin and insertion

All originate from the surface of the skull bone (rarely the fascia) insert on the dermis of skin

Clinical consideration of the facial muscles

An inability to form facial expressions on one side of the face may be the first sign of damage to the seventh cranial or facial nerve that innervates the muscles of facial expression. Nerve damage results in facial paralysis of facial expression on the involved side Paralysis is the loss of voluntary muscle action that can be on either a temporary or permanent basis

Levator Anguli Oris Muscle

Deep to both the zygomaticus major and zygomaticus minor muscles of facial expression in the oral region is the levator anguli oris muscle.

Depressor Labii Inferioris Muscle

Deep to the depressor anguli oris muscle is the depressor labii inferioris, a small quadrilateral muscle of facial expression in the oral region.

Clinical Note: Orbicularis Oris Muscle Loss of Use

If a patient does not have the ability to close the lips, the patient may experience excessive drooling. This can occur after a stroke (cerebrovascular accident, CVA) or other neurological events and syndromes.

Sternocleidomastoid Muscle: Action

If one muscle contracts, the head and neck bend to the unilateral side, and the face and front of the neck rotate to the contralateral side. If both muscles contract, the head will flex at the neck and extend at the junction between the neck and skull.

two cervical muscles

Sternocleidomastoid trapezius superficially located on the neck serve to hold and stabilize the head as well as position the head in relation to the rest of the body

Trapezius Muscle: Action

The cervical fibers act to lift the clavicle and scapula-when the shoulders are shrugged

Levator Labii Superioris Alaeque Nasi Muscle

The levator labii superioris alaeque nasi muscleis a muscle of facial expression in the oral region

Mentalis Muscle

The mentalis muscle is a short, thick muscle of facial expression superior and medial to the mental nerve in the oral region

Corrugator Supercilii Muscle: Action

The muscle draws the skin of the eyebrow medially and inferiorly toward the nose causes vertical wrinkles in the glabella area of the forehead and horizontal wrinkles at the bridge of the nose, as when a person frowns

Levator Labii Superioris Muscle: Action

The muscle elevates the upper lip

Buccinator Muscle: Origin and Insertion

The muscle originates from three areas: the alveolar processes of both the maxilla and mandible, as well as a fibrous structure, the pterygomandibular raphe Between the origin and insertion, the fibers from the buccinator muscle intersect and take on an overall "braided" effect.

Platysma Muscle: Origin and Insertion

The muscle originates in the skin superficial to the clavicle and shoulder passes anteriorly to insert on the inferior border of the mandible and into the other muscles surrounding the mouth

Zygomaticus Minor Muscle: Origin and Insertion

The muscle originates on the body of the zygomatic bone inserts in the skin of the upper lip adjacent to the insertion of the levator labii

Corrugator Supercilii Muscle: Origin and Insertion

The muscle originates on the frontal bone in the supraorbital region passes superiorly and laterally to insert into the skin of the eyebrow

Depressor Anguli Oris Muscle: Origin and Insertion

The muscle originates on the inferior border of the mandible passes superiorly to insert into the skin at the ipsilateral labial commissure

Mentalis Muscle: Origin and Insertion

The muscle originates on the mandible near the midline inserts in the skin of the chin

Platysma Muscle

The platysma muscle is a muscle of facial expression that runs from the neck all the way to the mouth, superficial to the anterior cervical triangle and external jugular vein.

Risorius Muscle: Origin and Insertion

The risorius originates from fascia superficial to the masseter passes anteriorly to insert into the skin at the ipsilateral labial commissure

Orbicularis Oris Muscle: Origin and Insertion

The vermilion zone fibers of the muscle encircle the mouth between the skin and labial mucosa of the lips, with no bony attachment These fibers then insert into the skin of the lips at both labial commissures

Orbicularis Oris Muscle: Action

This muscle has four relatively distinct movements: pressing together (closing lips) tightening and thinning (pursing lips) rolling inward between the teeth (grimacing) thrusting outward (pouting and kissing)

Levator Labii Superioris Alaeque Nasi Muscle: Origin and Insertion

This muscle originates from the frontal process of the maxilla passes inferiorly to insert into two areas: the skin of the ala of the nose and upper lip

Levator Anguli Oris Muscle: Origin and Insertion

This muscle originates in the canine fossa of the maxilla, usually superior to the root of the maxillary canine passes inferiorly to insert into the skin at the ipsilateral labial commissure

Platysma Muscle: Action

This muscle raises the skin of the neck to form noticeable vertical and horizontal ridges and depressions. It can also pull the labial commissures down, as when a person grimaces.

Epicranial Muscle is separated by what

a large, spread-out scalpal tendon, the epicranial aponeurosis or galeaaponeurotica

Zygomaticus Minor Muscle

a small variable muscle of facial expression in the oral region, medial to the zygomaticus major muscle

Risorius Muscle

a thin muscle of facial expression in the oral region

Risorius Muscle: Action

acts to stretch the lips laterally, retracting the labial commissure widens the mouth thought (erroneously) to produce "grinning" or "smiling" really produces more of a grimace Joker grin

Orbicularis Oculi Muscle: Action

closes the eyelid If all fibers are active, the eye can be squinted, and wrinkles or "crow's feet" form at the lateral canthus

Depressor Anguli Oris Muscle :Action

depresses the labial commissure when a person frowns

Depressor Labii Inferioris Muscle: Action

depresses the lower lip, exposing the mandibular incisor teeth Some experts have suggested that it expresses irony

muscular divisions of the head and neck

divided off of functions cervical muscles muscles of facial expression muscles of mastication hyoid muscles muscles of the tongue muscles of the pharynx

Epicranial Muscle-two bellies

frontal occipital

The epicranial aponeurosis insertion and orgin

frontalis muscle (frontal belly) inserts into the skin of the eyebrow and root of the nose occipitalis muscle (occipital belly) originates from both the superior nuchal line of the occipital bone and the mastoid process of the temporal bone and then inserts in the epicranialaponeurosis

orbicularis oris muscle

important in the oral region acts to shape and control the size of the mouth opening creates the lip positions and movements during speech

action of the muscle

movement that is accomplished when the muscle fibers contract

Muscles of Facial Expression: Action

muscles contract = the skin moves cause wrinkles at right angles to the muscles' action line act in various combinations to show varying expressions to change the appearance of the face similar to the muscles of mastication

Buccinator Muscle: Action

pulls each labial commissure laterally and shortens the cheek both vertically and horizontally this action causes the muscle to keep food pushed back on the occlusal or masticatory surface of the posterior teeth, as when a person chews assists the muscles of mastication by keeping the food in the correct position when chewing trumpet muscle

Mentalis Muscle: Action

raises the chin, wrinkling the skin, causing the displaced lower lip to protrude, narrowing the oral vestibule when active, fibers may dislodge a complete denture in an edentulous patient with loss of alveolar process height

A muscle in the muscular system

shortens under neural control, causing soft tissue and bony structures of the body to move. each muscle is attached at both ends of these moving structures each end is categorized according to its role in movement

Clinical Note: Orbicularis Oris Muscle and Smoking Habit

shows more defined wrinkling with cigarette use or other prolonged oral habits point out within tobacco cessation discussions

Pterygomandibular Raphe (Fold)

tendinous band located posterior to the most distal mandibular molar as it spans the area between the mandible and the point at which the hard and soft palates meet it is noted on a patient in the oral cavity as the pterygomandibular fold a landmark for the administration of the inferior alveolar (IA) block

orgin

the end of the muscle that is attached to the least movable structure

insertion

the other end of the muscle and is attached to the more movable structure

Buccinator Muscle

thin quadrilateral muscle of facial expression forms the anterior part of the cheek or the lateral wall within the buccal region of the oral cavity

Depressor Anguli Oris Muscle

triangular muscle of facial expression in the inferior oral region