Muscles of the Head and Neck

Orbicularis Oris Muscle (round, mouth) Description: encircles the mouth Origin: *NOT on bone (an exception); lies around the lips Inserts: angles of the mouth, philtrum Action: purses and closes lips (pucker-contracts)

(Facial Expression Muscle) What muscle is this?

Closing: masseter, temporalis, medial pterygoid. Opening: anterior suprahyoids, inferior head of lateral pterygoids.

For movements of speech/mastication what are the bilateral muscles involved in closing and opening?

What is a muscle?

Muscles contract and lengthen when stimulated by nerves, thereby moving the structures they are attached to. Originates on bone and inserts on skin.

What general information is there to know about the muscles of mastication?

Muscles of mastication are four paired muscles that are located deeper within the face than the muscles of facial expressions. These muscles are attached in some manner to the mandible and include: the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles. They are responsible for closing/opening jaw, moving it in coordination with TMJ to produce its motions of depression, elevation, protrusion, retraction, and lateral deviation. All muscles of mastication are innervated by branches of mandibular nerve of the fifth cranial or trigeminal nerve, with each nerve serving one side of the face.

Prefixes- What does ORB, OCULI, ORIS, LABI, LEVATOR, DEPRESSOR stand for?

ORB: round OCULI: the eye ORIS: oral LABI: the lip LEVATOR: to elevate or rise DEPRESSOR: to lower

Define muscle origin and muscle insertion.

Origin: end of muscle attached to the least moveable structure. (Most of the time part of bone-Fixed: does not move) Insertion: end of the muscle attached to the more moveable structure; insertion moves toward the origin.

They are mastication muscles because they help with swallowing. They hyoid bone is inferior to the mandible; it does not articulate with any other bone so it uses only muscular and ligamental attachments through the hyoid muscles to stabilize.

What are hyoid muscles?

Muscles found below the hyoid bone; most depress the hyoid and larynx, facilitates swallowing. All innervated by the 2nd and 3rd cranial nerves) There are 4: sternothyroid, sternohyoid, omohyoid, thyrohyoid.

What are infrahyoid muscles?

Muscles found above the hyoid bone. (Also categorizes as anterior and posterior) There are 4: digestive, mylohyoid, geniohyoid, stylohyoid. All elevate the hyoid bone and larynx (swallowing); Also closes the mandible.

What are suprahyoid muscles?

1) Gliding 2) Rotating 3) Lateral Deviation 4) Movements of speech/mastication

What are the 4 TMJ movements?

There are 5: palatoglossus, palatopharyngeus, levator veli Palatine, tensor veli palatine, and the muscle of uvula. Forms the posterior area of the palate and connects laterally with the tongue. It helps with speaking and swallowing. Extend over the anterior oropharynx to prevent food from entering the nasal cavity. All are innervated by the pharyngeal plexus of nerves.

What are the muscles associated with the soft palate and uvula and general function?

Pharyngeal Constrictor Muscle Group: A series of 3 muscles that overlap each other, wrapping around the pharynx; consists of superior, middle and inferior pharyngeal constrictors which forms the lateral borders of the soft palate. Moves food; facilitates swallowing. All insert on the median pharyngeal raphe. 1) superior pharyngeal constrictor: origin: pterygoid hamulus, mandible, pterygomandibular raphe. 2) middle pharyngeal constrictor: origin: hyoid bone, stylohyoid ligament. 3) inferior pharyngeal constrictor: origin: thyroid and cricoid cartilages (lower in throat)

What are the three muscles? (1) (2) (3)

Temporomandibular Joint is the movement of mandible and cranium. It is made up of- 1) Temporal bone: (articular eminence-holds condyle in place, articular fossa, postglenoid process-holds condyle in place). 2) Mandible: (condyle-fits into the articular fossa, coronoid process, mandibular notch)

What bones make up the TMJ?

It is a fibrous tissue which encloses the TMJ (condyle, articular fossa and postglenoid eminence). NO blood vessels are present in the capsule tissue. The purpose is to protect joint from wear and tear.

What does the fibrous capsule do?

Can be acute or traumatic. Symptoms: tenderness, swelling, muscle spasms, limited opening. Diagnosis: palpating of TMJ and associated muscles, x-rays, MRI. Causes: behavioral stress, grinding, clenching, malocclusion, osteoarthritis, aging disc, trauma, hormones. (More cases in women) Most of the time that it is most likely a combination of multiply factors.

What is TMD, how would it be diagnosed and what causes it?

Union of 2 or more bones which move upon each other.

What is a joint?

Within the uvula (a projection of tissue on posterior portion of soft palate) no specific origin or insertion. Action: shortens and broadens the tissue to close off the pharyngeal wall from the nasopharynx, which prevents aspiration into the lungs. Some people don't have one or get it removed.

What is the description and action of the uvula muscle and what makes it so unique?

Looks like a meniscus made of fibrous tissue. Made to the shape of the head of the condyle. It has synovial cavities (space between disc and bone)-superior: above, inferior: below. There is synovial fluid that is produced and can be found on the inside of the join capsule . This to fill the cavities and lubricate the joint.

What is the disc for TMJ and what are some of its characteristics?

DOES NOT directly attach to the temporal bone- it attaches indirectly through the capsule. Disc does not have any blood vessels or nerves, but are behind it does because it is fully vascular. (Uses lateral pterygoid muscle)

What is there to know about the disc attachments for the TMJ?

There are two categories: 1) intrinsic: muscles within the tongue- superior longitudinal, inferior longitudinal, transverse, vertical. (All intrinsic and extrinsic are innervated by the 12th cranial nerve) 2)extrinsic: muscles outside that attach to the tongue. Median septum separates muscles; visible by the sulcus on the dorsal side of the tongue; very complex movements.

What is there to know about the muscles of the tongue and what are the two categories?

TMJ ligament: attaches lateral to the joint, on lateral side of the mandible- from zygoma to the neck of the condyle (goes to zygomatic bone). Stabilizes the joint capsule and prevents retraction of the MN

What is this ligament? (1)

Spenomandibular Ligament: Attaches on the medial sides of the mandible- from sphenoid to the lingula. Is a landmark for local anesthesia.

What ligament is this?

Stylomandibular Ligament: attaches from styloid process to the angel of the mandible.

What ligament is this? (2)

Intrinsic: Superior Longitudinal: superficial; shorter, thicker, runs oblique and longitudinal on dorsal surface from base of tongue to its apex; shortens/thickens tongue. (Life up and thicken)

What muscle is this and is in extrinsic or intrinsic? (1)

Styloglossus muscle: Extrinisc Origin: styloid process Insert: at apex and base of the tounge

What muscle is this and is in intrinsic or extrinsic? (1)

Hyoglossus Muscle: Extrinisc- thicker, connects hyoid bone to tongue. Origin: greater Cornu of the hyoid bone. Inserts: lateral areas of the tongue (side of tongue)

What muscle is this and is in intrinsic or extrinsic? (2)

Intrinsic: Transverse: runs transversely from median septum to lateral sides. Horizontal-meet in middle. Vertical: runs vertically from dorsal to ventral sides of tongue.

What muscle is this and is it extrinsic or intrinsic? (2)

Intrinsic: Inferior longitudinal: long, narrow, runs horizontally on ventral surface from base to apex of tongue; shortens and thickens appearance of the tongue.

What muscle is this and is it extrinsic or intrinsic? (3)

Genioglossus muscle: Extrinsic-fan shaped; superior to the geniohyoid. Origin: genial tubercles Inserts: on tongue, from base to apex.

What muscle is this and it is extrinsic or intrinsic? (4)

Levator Veli Palatini Muscle: tiny- when contracts lifts back of throat. Centered; superior to the soft palate. Closes nasopharynx when speaking and swallowing. Origin: inferior part of temporal bone. Inserts: median palatine raphe.

What muscle is this? (1)

Palatoglossus Muscle: fibrous, long, thin; forms the anterior tonsillar pillar (back of mouth to side of tongue). Origin: median palatine raphe Inserts: lateral sides of the tongue

What muscle is this? (3)

Palatopharyngeus Muscle: forms the posterior tonsillar pillar (back of throat down to cartilage). It moves the soft palate to close the nasopharynx during swallowing. Origin: soft palate Inserts: Laryngopharynx and thyroid

What muscle is this? (3)

Helps with speaking, swallowing, middle ear function. Consists of stylopharyngeus, pharyngeal constrictor group, soft palate muscles.

What muscles are part of the pharynx and what do they do?

Stemocleidomastoid: Description- Largest, most superficial, thick, neck landmark; divides into anterior and posterior cervical triangles; paired. Origin- Medial portion of clavicle, superior of sternum. Inserts- Mastoid process of temporal bone. Action- Bends head side to side.

(Cervical Muscle)- What muscle is it?

Trapezius: Description- Broad, flat, triangular shape, covers lateral and posterior neck; paired. Origin- Occipital bone and cervical/thoracic regions. Inserts- Clavicle, scapula. Action- Shrugs the shoulders.

(Cervical Muscle)- What muscle is it?

Buccinator Muscle: Description: paired; anterior part of the cheek; deep within; lies horizontally positioned. 3 Origins: 1) alveolar process of maxilla 2) mandible 3) pterygomandibular raphe Inserts: angle of the mouth Action: shortens the check, keeps food in the areas of the molars, assists chewing

(Facial Expression Muscle) What muscle is this?

Mentalis Muscle Description: paired; short, thick, beneath depressor labii inferioris (strong) Origin: Mandible-near the midline Inserts: chin Action: Raises skin on the chin, protrudes lower lip (pout), is the muscle of the lower lip hygienists "fight" with.

(Facial Expression Muscle) What muscle is this?

Platysma Muscle (Not cervical muscle- because helps with facial expressions) Description: paired: very long, flat and broad; runs from neck up to the mouth; covers the anterior cervical triangle. Origin: on the skin above the clavicle and shoulder Inserts: lower border of the mandible and mouth (corners) Action: raises skin of the neck; pulls corner of the mouth down (grimace muscle), shows early signs of agin when tone is lost (neck wrinkles)

(Facial Expression Muscle) What muscle is this?

Rigorous Muscle: (superficial) Description: paired; thin muscle, runs horizontally from the corners of the mouth. Origin: Fascia above the masseter muscle. Inserts: corners of the mouth. Action: widens the mouth, SMILE muscle

(Facial Expression Muscle) What muscle is this?

Zygomaticus Major Muscle (major below bigger) More posterior to minior Description: paired; runs diagonally of the upper lip Origin: zygomatic bone Inserts: angle of the mouth Action: Elevates the upper lip and moves it laterally; SMILE muscle

(Facial Expression Muscle) What muscle is this? Number Five

Levator Anguilla Oris Muscle (Deeper muscle) runs vertically Description: paired; beneath both zygomaticus muscles Origin: canine fossa (superior to the apex of the cuspid) Inserts: corners of the mouth Actions: elevates angle of the mouth; SMILE muscle

(Facial Expression Muscle) What muscle is this? Number Four

Depressor Labii Inferioris Muscle (lips) Description: paired; beneath depressor anguli oris and below lips; runs vertically Origin: lower border of the mandible Inserts: lower lip Action: depresses the lower lip; "bares" the lower incisors

(Facial Expression Muscle) What muscle is this? Number One

Levator Labii Superioris Alaeque Nasi Muscle (lift lips nose) (Closer to side of nose) Description: paired, runs anterior and parallel to levator labii superioris. Origin: frontal process of the maxilla. Inserts: on the ala, upper lip. Action: flares nostrils, lifts upper lip

(Facial Expression Muscle) What muscle is this? Number One

Zygomaticus Minor Muscle (minor above smaller) Description: paired; medial to the zygomaticus major Origin: zygomatic bone Inserts: upper lip Action: elevates the upper lip

(Facial Expression Muscle) What muscle is this? Number Three

Depressor Anguli Oris Muscle (Corner of mouth) Description: paired; triangular shape; in area below the mouth; runs vertically. Origin: lower border of the mandible Inserts: angle of the mouth Actions: depresses angle of the mouth; FROWN muscle

(Facial Expression Muscle) What muscle is this? Number Two

Levator Labii Superioris Muscle (lift-lip) Can't lift lower lip Description: paired, broad, flat, above the upper lip, runs vertically. Origin: infra orbital part of the maxilla Inserts: lateral sides of upper lip Action: "Elvis"- elevates the upper lip

(Facial Expression Muscle) What muscle is this? Number Two

Corrugated Supercilli Muscle Description: superior to orbicularis oculii Origin: frontal bone, supra orbital region Inserts: tissues of the eyebrow (skin on eyebrows) Action: frowning, draws eyebrows together.

(Facial expression muscle) Number 1

Orbicularis Oculi Muscle: (round, eye)-from name Description: encircles the eye Origin: orbital rim, nasal process of frontal bone, frontal process of maxilla Inserts: skin, lateral eye, circular Action: squinting, closes eyelid

(Facial expression muscle) Number 2

Epicranial muscle: Covers scalp area; has 2 bellies; separated by the "epicranial aponeurosis" (a tendon) where the parietal and occipital bones meet. Origin- (front belly): from epicranial aponeurosis Origin- (occipital belly): from occipital bone and mastoid process Inserts- (frontal belly): eyebrows, root of nose Inserts (occipital belly): epicranial aponeurosis Action: Raises eyebrows, moves the scalp.

(Facial expression muscle) What are both of these?

Mylohyoid Muscle: deep to the digastric; transverse fibers (horizontal); *forms floor of mouth* Large broad muscle. Origin/Inserts: R & L fibers originate from lingual border of the MN and unite at the midline; most posterior fibers are on the hyoid bone.

(Hyoid-Suprahyoid Muscle) What muscle is this? (2)

Stylohyoid Muscle: (sphenoid) attaches directly onto bone. Thin; superficial to the digastric muscle. Origin: styloid process Inserts: hyoid bone

(Hyoid-Suprahyoid Muscle) What muscle is this? (3)

Digastric Muscle: fairly long. 2 bellies (anterior and posterior) they lie beneath the chin. Helps pull chin down. Origin: (anterior belly): on an intermediate tendon that is attached to the greater Cornu of the hyoid bone. Origin: (posterior belly): mastoid notch (medial to the mastoid process. Inserts: (anterior belly): inner side of the MN at the symphysis. Inserts: (posterior belly): onto the same intermediate tendon.

(Hyoid-Suprahyoid Muscle) what muscle is this? (1)

Geniohyoid Muscle: Found deep to the mylohyoid. (#2 is mylohyoid msucle) Origin: medial side of the MN, at the genial tubercle (one corner to the next) Inserts: body of the hyoid bone.

(Hyoid-Suprahyoid Muscle) what muscle is this? (1)

Stemohyoid Muscle (bigger); superficial to sternothyroid, thyroid gland and cartilage. Origin: sternum-near where it joins the clavicle. Inserts: body of the hyoid.

(Infrahyoid Muscle-Hyoid Muscle) What muscle is this? (1)

Sternothyroid Muscle (thin); superficial to the thyroid gland. Depresses thyroid cartilage and larynx. Origin: posterior surface of sternum. Inserts: thyroid cartilage

(Infrahyoid Muscle-Hyoid Muscle) What muscle is this? (2)

Omohyoid Muscle: lateral to the sternothyroid; has a superior and inferior belly. Origin (inferior belly): scapula, crosses the jugular and stermocleidomastiod. Inserts (inferior belly): by a tendon to the superior belly. Origin (superior belly): from a tendon attached to the inferior belly. Inserts (superior belly): on the lateral body of the hyoid bone. (All insert on hyoid bone)

(Infrahyoid Muscle-Hyoid Muscle) what muscle is this? (4)

Thyrohyoid Muscle: deep beneath the omohyoid, and is a continuation of the sternothyroid muscle. Origin: thyroid cartilage Inserts: body and greater Cornu of the hyoid bone.

(Infrahyoid Muscle-Hyoid Muscle) what muscle is this? (5)

Masseter Muscle Most superficial, broad, large, strongest, easily overdeveloped. 2 heads. Elevates the mandible (closes jaw) Origin (superficial head): from lower border of zygoma on the anterior two thirds area (mandible) Origin (deep head): posterior and middle of zygoma (back part) Inserts (superficial head): on lateral surface of the mandible (outside of bone) Inserts (deep head): on ramus

(Mastication Muscle) What muscle is this?

Temporalis Muscle Fan shaped, within temporal fossa (broad-thin) If entires muscle contracts it elevates the MN (moves up and to side). If only posterior portion contracts it retracts the MN (lifting mandible up). Origin: inferior temporal line of temporal bone (originates on temporal bone0 Inserts: coronoid process of MN (first hum)

(Mastication Muscle) What muscle is this?

Medial Pterygoid Muscle (vertical) Deeper muscles, elevates the MN. Origin: pterygoid fossa on medial surface of pterygoid plate (sphenoid). Inserts: medial surface of the angle of the MN.

(Mastication Muscle) What muscle is this? (2)

Lateral Pterygoid Muscle (horizontal) Deep within the infratemporal fossa; has two heads: superior and inferior. If both sides contract together-protrudes the jaw (pulls in). If only one side contracts- causes lateral deviation of jaw movement. Origin (superior head): inferior surface of greater wing of spheniod. Origin: (inferior head): lateral surface of lateral pterygoid plate of the sphenoid. Inserts: pterygoid fovea (anterior side of the condyle) by second hump on MN.

(Mastication Muscle) what muscat is this? (1)

Stylopharyngeus Muscle: paired muscle, elevates and widens the pharynx. Origin: styloid process Inserts: lateral and posterior pharyngeal walls of the pharynx.

(Pharynx) What muscle is this? (2)

What is pterygomandibular raphe?

(Spheniod bone) Fibrous tissue Extends vertically, at about the arenas of the angle of the jaw. Runs from the hamulus to the mylohyoid line. Muscles attach to it (buccinatior, superior pharyngeal constrictor) Can be palpated Intra orally.

What are some facts about muscles of facial expressions.

-All paired; all innervated by the 7th cranial (facial) nerve. -All inserts on the skin; wrinkles occur at right angles to the action line of the muscle. -Many combinations of actions; forms all facial expressions. -Damage to the facial nerve (doesn't keep muscles working) from stroke, Bell's palsy, parotid gland cancer, surgery, trauma, local anesthesia, can cause loss of motor function and ability to form facial expressions.

Age- very thick and dense in youth; gets thinner, perforated with age and use. Injury- can dislocate the disc forward if posterior attachment sustains a blow.

Can the disc of the TMJ change and if so what causes that?

Crunching or clicking sound occurring with TMJ movement. Disc is dislocated or caught between the condylar head and the articular eminence. (Where disc is pushed out of spot, you can have crepitis and not TMD because it is not always accompanied by pain)

Define Crepitis?

Muscles go into spasms. Opened to long or open to wide.

Define Trismus?

Can't open or shut. Total dislocation of both joints. May be caused by upper-opening of the mouth. Both condyles move ahead of the articular eminence. Mouth is caught open. Treated manually moving the mandible down and back.

Define subluxation?

Movement occurs within upper synovial cavity between the disc and articular eminence. Both disc and condyle move forward/backward up and down the eminence.

Describe gliding for the TMJ?

Involves both glowing and rotating. One disc moves while the other remains stable (rotation is around the stable condyle).

Describe lateral deviation (lateral excursion) for the TMJ?

Movement occurs within lower synovial cavity between the disc and the condyle. Mandible is depressed or elevated.

Describe rotating for the TMJ?

Define action.

Describes the movement produced.