Muscular System Flashcards
Muscles are formed from ______ which forms the bulk of the mesoderm.
Myoblasts of the Mesenchyme
The human body has more than _____muscles
600
Muscles are _____ of the body’s mass.
40-50%
_______shorten under neural control
Skeletal muscles of the head and neck
Skeletal muscles of the head and neck shorten under neural control causing
soft tissue and bony structures to move
When muscles move the resulting muscle movement is called the
action of the muscle
Each muscle is attached at both ends of these moving structures:
•Origin - the end of the muscle attached to the least movable structure
• Insertion - the end of the muscle attached to the more movable structure
What are origins of muscles?
the end of the muscle attached to the least movable structure
What is the insertion of a muscle?
the end of the muscle attached to the more movable structure
Muscles in the head and neck can be divided into what 6 main groups?
• Cervical muscles
• Muscles of facial expression
• Muscles of mastication
• Hyoid muscles
• Muscles of the tongue
• Muscles of the pharynx
Sternocleidomastoid muscle and the trapezius muscles are what kind of muscles?
Cervical muscles
The SCM and trapezius muscle is superficially or deeply located on the neck?
Superficially
Hold and stabilize the head
Position the head in relation to the
rest of the body
SCM and trapezius muscle
One of the largest and most superficial
muscles of the neck
Paired muscle
Thick
Primary muscular landmark of the neck during EO examination
SCM muscle
• Divides each side of the neck diagonally into an anterior and posterior cervical triangle
SCM muscle
Where is the origin of the SCM muscle?
medial part of the clavicle and sternum’s superior and lateral surfaces
Where is the insertion of the SCM muscle?
mastoid process of the temporal bone
What is the action of SCM muscle?
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 flexes at the neck, and extend at the junction of the neck and skull
• This muscle assists in elevating the thorax during breathing
The SCM muscle is innervated by
Eleventh (XI) cranial nerve (accessory nerve)
the SCM is examined during an EO examination by
palpation
What is Palpation?
a physical examination technique that involves using the hands or fingers to feel the body in order to examine organs or body parts
When palpating the SCM muscle how should we position to the patient’s head to make their SCM more prominent?
turn their head to the contralateral side
Having the patient turn their head contra-laterally to palpate the SCM muscles increases accessibility for effective palpation of nearby
cervical lymph nodes
The insertion of the SCM into the mastoid process is just_____ to the external acoustic meatus
posterior and inferior
What is Torticollis?
• Spasm of the SCM
Torticollis causes
pain, tightening, or turning of the neck
Torticollis can cause the head to be tilted due to the intense spasm of the SCM. The head bends toward ______face turns____
affected side; away
•Broad, flat, triangular paired muscle superficial to both the lateral and posterior surfaces of the neck
Trapezius muscle
Where is the origin of the trapezius muscle?
external surface of the occipital bone and posterior midline of the cervical and thoracic regions
Where is there insertion of the trapezius muscle?
lateral third of the clavicle and parts of the scapula
What is the action of the trapezius muscle?
The cervical fibers of the trapezius muscle act to lift the clavicle and scapula; Shrugging motion
What is the innervation for the trapezius muscle?
• Eleventh (Xl) cranial nerve (accessory nerve)
the trapezius is examined during an EO examination by
palpation
During EOE, we use the trapezius as a “base” to feel for other structures such as
cervical lymph nodes
The trapezius muscle is the most responsive muscle in the body to emotional stress - the reaction is_______
tightness and muscle pain!
________can soothe a hygienist’s sensitive trapezius muscle after long hours of patient care
Relaxation exercises and regular self-care
Name some cervical muscle pathology in DH when providing patient care
Injury to cervical muscles may not allow the patient to be able to be positioned as you normally would for hygiene treatment
Patients may not be able to turn their head, tilt or lift their chin, etc.
Patients may not be able to sit in an ergonomically correct position in a dental chair and may require additional supports and stabilizers
Having the patient in a slightly upright position and slightly turned to one side may help lessen these problems for the patient. This may be at the expense of the comfort of the clinician. Limited appointment times may be best for both parties. What problems may need this consideration?
Injury to cervical muscles may not allow the patient to be able to be positioned as you normally would for hygiene treatment
• Paired muscles located within the superficial fascia of the
facial tissue
Muscles of facial expression
All muscles of facial expression originate
from_______ and
insert on the_______.
the surface of the skull bone; dermis of the skin
When these type of muscles contract, the skin of the face moves
Muscles of facial expression
During facial expression,__________ act in various
combinations to show varying expressions to change the appearance of the face; this group involvement is similar to the muscles
of mastication
the muscles of facial expression
All muscles of facial expression are innervated by the
seventh (VII) cranial nerve, the facial nerve
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 ____of facial expression on the involved side
facial paralysis
What is Paralysis?
the loss of voluntary muscle action that can either be temporary or permanent
Facial paralysis can occur with
• Stroke (or cerebrovascular accident)
• Bell’s palsy
• Parotid salivary gland cancer
AKA Epicranius
Epicranial Muscle
Muscle of facial expression in the scalp region
Epicranial muscle
The epicranial muscle has how many bellies?
Two bellies
What are the two bellies of the epicranial muscle?
Frontal belly and occipital belly
The frontal belly of the epicranial muscle is called the
frontalis muscle
Occipital belly of the epicranial muscle is called
the occipitalis muscle
The two bellies of the epicranial muscle are separated by a
large tendon, the epicranial aponeurosis or galea aponeurotic
The origin of the epicranial muscle
Occipital belly originates from the superior nuchal line of the occipital bone and the mastoid process of the temporal bone
The Insertion of the epicranial muscle?
Frontal belly inserts into the skin of the eyebrow and root of the nose
The action of epicranial muscle?
Both bellies raise the eyebrows and scalp when a person shows surprise. The two bellies of epicranial muscle can also act independently of each other
This muscles Encircles the orbit
Orbicularis Oculi
Name means “encircling eye orifice”
Orbicularis Oculi
The eyelid muscle - extends in a wide, circular fashion around the orbit
Orbicularis oculi
Interdigitates with the muscles of expression of the brow
Eyelid muscle or orbicularis oculi
Origin of orbicularis oculi
Originates from the orbital rim, nasal process of the frontal bone, and the frontal process of the maxilla
Insertion of the orbicularis oculi
Inserts into the skin at the lateral canthus
Action of orbicularis oculi
• Closing the eyelid
• Squinting
What are the Important functions of the orbicularis oculi?
Protecting the eye
Moistening the eye
• Muscle in the orbital region deep to the superior part of the orbicular oculi muscle
Corrugator Supercili
Name means “wrinkler of the eyebrow”
Corrugator Supercilii
Origin of Corrugator Supercili
Originates from the supraorbital region of the frontal bone
Insertion of Corrugator Supercili
Inserts into the skin of the eyebrow
Action of Corrugator Supercilii
Draws the skin of the eyebrow medially and inferiorly toward the nose
Causes vertical wrinkles in the glabella area of the forehead
Corrugator Supercili
Causes horizontal wrinkles at the bridge of the nose
This is one of the targeted muscles for Botox!
Corrugator Supercili
• Muscle in the oral region that shapes and controls the size of the mouth opening
Orbicularis Oris
Important for positioning and moving lips for speech
Name means “encircling orifice/mouth”
Orbicularis oris
• Origin of orbicularis oris
- Originates from the facial modiolus at the labial commissure
What is facial modiolius?
a small fibromuscular structure at the corner of the mouth where fibers from multiple facial muscles converge, and helps coordinate the action of these muscles
Where is the Insertion of the orbicularis oris?
Inserts into the tissues of the upper and lower lips
Action of orbicularis oris?
• Pressing lips together (closing lips)
• Tightening and thinning lips (pursing lips)
• Rolling lips inward between the teeth
• Pouting and thrusting lips outward (kissing)
Loss of function of this muscle may lead to excessive drooling due to the inability to close one’s mouth
Orbicularis oris
Loss of function of orbicularis oris muscle can occur after
a stroke (CA) or other neurological events and syndromes
Patients who have lost function in the orbicularis oris muscle may not be able to _____around the saliva ejector
close their mouths
If patients who have loss function in their orbicularis oris muscle can’t close around the saliva ejector, what do you do?
Let them hold a tissue to wipe the corner of their mouth whenever they need to
Consider feelings of embarrassment and treat the patient with dignity
Smoking and other oral habits can “overuse” this muscle, causing more defined wrinkles
Orbicularis oris
Muscle that forms the anterior part of the cheek or the lateral wall within the buccal region of the oral cavity
Buccinator
• Pierced by the parotid duct
Buccinator muscle
Origin of the buccinator muscle?
Originates from three areas
• Alveolar process of the maxilla
•Alveolar process of the mandible
•Pterygomandibular raphe/fold
Insertion of the buccinator muscle?
Inserts into the tissues of the orbicular oris at the corners of the mouth
Action of the buccinator muscle?
Pulls the labial commissure laterally, shortening and compressing the cheek
Assists the muscles of mastication by keeping food in the correct position during chewing
Called the “trumpet muscle” because of its importance in forcefully expelling air
In infants, this muscle provides suction for nursing
• A thin muscle in the oral region that stretches the lips laterally, widening the mouth; produces a “grimace” or a stretched out grin
Risorius
Origin of risorius?
Originates from the fascia superficial to the masseter
Insertion of Risorius?
Inserts into the skin at the ipsilateral labial commissure at the facial modiolus
Action of Risorius muscle?
Stretches the lips laterally, widening the mouth
• Produces a “grimace” or a stretched out grin
A broad, flat muscle in the oral region; Name means “lifter of the upper lip”
Levator Labii Superioris
Origin of Levator Labii Superioris?
Originates from the infraorbital rim of the maxilla
Insertion of Levator Labii Superioris
Skin of the upper lip at the ipsilateral labial commissure of the facial modiolus
Action of Levator Labii Superioris
Elevates the upper lip in a smile
Located in the oral region; known as the elvis muscle
Levator Labii Superioris Alaeque Nasi
Muscle of the oral region; Originates from the frontal process of the maxilla
Levator Labii Superioris Alaeque Nasi
Inserts into two areas: The skin at the ala of the nose and the skin at the upper lip
Levator Labii Alaeque Nasi
Action of the Levator Labii Superioris Alaeque Nasi
Elevates one side of the upper lip towards the nose, dilating the nostril (naris)
Creates a sneer/snarl
• Located in the oral region; Located lateral to the zygomaticus minor muscle
Zygomaticus Major
Origin of zygomaticus major muscle:
Originates from the zygomatic bone
Insertion of zygomaticus major muscle:
Inserts into the skin at the ipsilateral labial commissure and the facial modiolus, in and around the orbicular oris
Action of the zygomatic major muscle
Elevates the labial commissure of the upper lip, pulling it laterally when a person smiles
Located in the oral region, Small, variable muscle; Located medial to the zygomaticus major muscle
Zygomaticus Minor
Origin of zygomaticus minor muscle:
Originates from the body of the zygomatic bone, medial to the zygomaticus
major muscle
Insertion of zygomaticus minor muscle
Inserts into the skin at the upper lip adjacent to the insertion of the levator labii superioris
Action of zygomaticus minor:
Elevates the upper lip, assisting in smiling
Located in the oral region; Located deep to both the zygomaticus major and zygomaticus minor muscles
Levator Anguli Oris
Name means “lifter of the angle of the mouth”
Levator Anguli Oris
Origin of Levator Anguli Oris muscle:
Originates from the body of the canine fossa of the maxilla, usually superior to the root of the maxillary canine
Insertion of Levator Anguli Oris muscle:
Inserts into the skin at the ipsilateral labial commissure at the facial modiolus
Action of Levator Anguli Oris muscle:
Elevates the labial commissure, as when a person smiles
Located in the inferior oral region; Located deep to both the zygomaticus major and zygomaticus minor muscles
Depressor Anguli Oris
Name means “depressor of the angle of the mouth”
Depressor Anguli Oris
Origin of Depressor Anguli Oris muscle:
Originates from the body of the inferior border of the mandible
Insertion of Depressor Anguli Oris:
Inserts into the skin at the ipsilateral labial commissure at the facial modiolus
Action of Depressor Anguli Oris:
Depresses the labial commissure, as when a person frowns
Small muscle in the inferior oral region; Located deep to the depressor anguli oris
Depressor Labii Inferioris
Name means “depressor of the lower lip”
Depressor Labii Inferioris
Origin of the Depressor Labii Inferioris
Originates from the body of the inferior border of the mandible
Insertion of the depressor labii inferioris
Inserts into the skin of the lower lip
Action of Depressor Labii Inferioris
Depresses the lower lip, exposing the mandibular incisors
Short, thick muscle in the oral and mental region; Located superior and medial to the mental nerve
Mentalis
Origin of mentalis:
Originates from the anterior mandible near the midline
Insertion of mentalis:
Inserts into the skin of the chin
Action of mentalis:
Raises the chin, wrinkling the skin and protruding the lower lip into a pout
Creates characteristic “peach pit” dimpling of the skin
Patients activating this muscle can make the vestibule shallower, making access more difficult during dental procedures
Mentalis
Paired. broad muscles located on either side of the neck
Runs from the neck to the mouth, superficial to the anterior cervical triangle and jugular vein
Platysma
Origin of Platysma
• Origin - Originates from the skin superficial to the clavicle and shoulder
Insertion of Platysma
• Insertion - Inserts into the muscles surrounding the mouth, including the facial modiolus
Action of Platysma
• Raises the skin of the neck to form noticeable vertical and horizontal ridges and depressions
• Also pulls the labial commissures down, like a grimace of horror or disgust
Four paired muscles that are located deeper within the face than the muscles of facial expression
muscles of mastication
What are the four paired muscles of mastication?
The masseter, temporalis, medial pterygoid, lateral pterygoid muscle muscles
These muscles are all attached in some manner to the mandible.
These muscles may be involved in pathology associated with the temporal mandibular joint
All of these muscles are in embryologic derivatives of the first branchial arch or mandibular arch
Muscles of mastication
The muscles of mastication generally originate on the___ and insert on the
cranium; mandible
These muscles work with the temporal mandibular joint to accomplish movements of the mandible so as to allow mastication
Muscles of mastication
Similar to the muscles of facial expression, these muscles can work in combination for mastication
Muscles of mastication
Mastication is the process of___
chewing food in preparation for swallowing and digestion
The muscles of mastication are responsible for
Closing the jaws, moving the lower jaw forward or backward and shifting the lower jaw to one side
The muscles of mastication are responsible for closing the jaw, moving the jaw forward, and backward and shifting the lower jaw to one side. These jaw movements involve the movement of the____ while the rest of the skull remains relatively stable.
mandible
The movements of the mandible include
Depression, elevation, protrusion, retraction, and lateral deviation
All muscles of mastication are innervated by
Branches of the mandibular nerve or third division of the fifth cranial or trigeminal nerve with each nerve serving one side of the face
The most superficial and one of the strongest mastication muscles
Masseter muscle
Broad thick, flat rectangular muscle on each side of of the face that is anterior to the parotid salivary gland
Masseter muscle
The masseter muscle has two heads that differ in depth called the
the superficial and deep heads
Both heads of the masseter muscle originate from
The zygomatic arch, but from differing locations
The superficial head of the masseter muscle originates from
The zygomatic process of the maxilla and from the anterior 2/3 of the inferior border of the zygomatic arch
The deep head of the masseter muscle originates from the
Posterior 1/3 and the entire medial surface of the zygomatic arch
The deep head of the masseter muscle is partly concealed by the
Superficial head of the muscle
Both heads of the masseter muscle pass inferiorly to insert on different parts of the external surface of the
Mandible
The superficial head of the masseter muscle inserts into the
lateral surface of the angle of the mandible
The deep head of the masseter inserts on the
Mandibular ramus superior to the angle of the mandible
Action of the masseter muscle
During bilateral contraction of the entire muscle: elevates demandable, raising the lower jaw. (Closing of jaw)
Innervation of the masseter muscle
Innervated by the masseteric nerve, branch of the mandibular nerve or third division of the fifth cranial or trigeminal nerve
Broad fan shaped muscle of mastication on each side of the head that fills the temporal fossa and is located superior to the zygomatic arch
Temporalis muscle
The muscle originates from the entire temporal fossa on the temporal bone
Temporalis muscle
Insertion of the temporalis muscle
the coronoid process of the mandible
Action of temporalis muscle;
If entire muscle contracts, the main action is to elevate the mandible, closing the jaw. If only posterior contracts, the muscle moves the lower jaw backward, retraction of the mandible.
Innervation of temporalis muscle
Deep temporal nerves, branches of the mandibular nerve (third division of fifth cranial nerve (trigeminal)
Why does the medial pterygoid muscle have two heads?
Due to their differing depth
Names of the two heads of the medial pterygoid muscle
Superifical and deep
Deepest muscle of mastication
Medial pterygoid
The larger deep head of the medial pterygoid muscle origin
Between the pterygoid plates of the sphenoid bone
Origin of smaller superficial head of medial pterygoid muscle
from the lateral surfaces of both the pyramidal process of the palatine bone and the maxillary tuberosity of the maxilla
Insertion of both heads of the medial pterygoid muscle
mandibular ramus and angle of the mandible
The masseter muscle is examined during an EO exam by
Palpation
How do we palpate the masseter muscle?
Place the fingers of each hand over the muscle and ask your patient to clench their teeth together several times
The masseter muscle can be enlarged in patients who
habitually clench or grind their teeth (bruxism), or habitual gum chewing
Action of medial pterygoid muscles
Elevates the mandible to close the jaw, helps out the masseter muscle but not as strong of an impact
Aka the internal pterygoid
Medial pterygoid
Aka the external pterygoid
Lateral pterygoid
Short thick muscle that lies within the infratemporal fossa, deep to the temporalis muscle
Lateral pterygoid
Does the lateral pterygoid have a superficial and deep head?
No, it has superior and inferior heads
The lateral pterygoid muscle is surrounded by which plexus of veins?
Pterygoid plexus of veins
What is the pterygoid plexus of veins?
A network of veins located in the infratemporal fossa of the skull
Origin of lateral pterygoid muscle
Superior head originates from the infratemporal surface and infratermporal crest of the sphenoid bone, and the Inferior head originates from the lateral surface of the lateral ptergoid plate of the sphenoid bone
Insertion of the lateral pterygoid muscle
Superior head inserts into the mandibular condyle at the pterygoid fovea, and also inserts partially on the TMJ disc and capsule; Inferior head inserts on the mandibular condyle at the pterygoid fovea
The only muscle of mastication that depresses the mandible
Lateral pterygoid
Action of the lateral pterygoid muscle
Depresses the mandible (opens the jaw)
If both muscles contract, it protrudes the jaw
If only one side contacts, lower jaw shifts to contralateral side
Innervation of lateral pterygoid
by a branch of the mandibular nerve (which is a division of the trigeminal nerve) called the lateral pterygoid nerve
a horseshoe-shaped bone suspended inferior to the mandible
Hyoid bone
Does the hyoid bone articulate with any other bone?
It does not
The hyoid bone is only connected to the rest of the body by
muscle attachments
These muscles assist in the actions of mastication and swallowing
Hyoid muscles
These muscles can be grouped based on their position to the hyoid bone
Hyoid muscles
The hyoid muscles are separated into what two groups?
Suprahyoid muscles
Infrahyoid muscles
Most of the hyoid muscles are in a______ position in the tissue of the neck
superficial
Both groups of the hyoid muscles are attached to the hyoid bone, except for the
sternothyroid muscle
This group of hyoid muscles is located superior to the hyoid bone
Suprahyoid muscles
The suprahyoid muscles can be further divided according to their horizontal position in relation to the hyoid bone. What are those divisions?
• Anterior suprahyoid muscle group
• Posterior suprahyoid muscle group
What are the anterior suprahyoid muscles?
•Anterior belly of the digastric muscle
•Mylohyoid muscle
•Geniohyoid muscle
What are the posterior suprahyoid muscles?
•Posterior belly of the digastric muscle
• Stylohyoid muscle
Do the hyoid muscles assist in mastication?
Yes
Two actions associated with mastication result from activation (contraction) of the______. Cause elevation of the hyoid bone and larynx (occurs during swallowing) and causes mandible to depress and jaws to open
Suprahyoid muscles
What are the two actions of the suprahyoid muscles that assist the muscles of mastication in mastication?
• Cause elevation of the hyoid bone and larynx (occurs during swallowing)
• Causes mandible to depress and jaws to open
The anterior belly digastric as apart of the anterior suprahyoid or the posterior suprahyoid?
Anterior suprahyoid
The posterior belly digastric is apart of the anterior or posterior suprahyoid muscle group?
Posterior
The digastric muscle is a suprahyoid muscle or infrahyoid muscle?
Suprahyoid muscle
The digastric muscle has two______ that demarcates the superior part of the anterior cervical triangle, and helps form parts of both the submandibular triangle and the submental triangle
Bellies
What are the two bellies of the digastric muscle called?
Anterior and posterior belly digastric
Origin of anterior belly digastric
Intermediate tendon of the digastric muscle
Insertion of the anterior belly digastric
inserts into the digastric fossa on the medial surface of the mandible,
Intermediate tendon of the digastric muscle is loosely attached to the ______of the hyoid bone
body and greater horn
Origin of the posterior belly digastric
Mastoid notch medial to the mastoid process of temporal bone
Insertion of the posterior belly digastric
Intermediate tendon of the digastric muscle
Action of the digastric muscles
Depresses the mandible and elevates the hyoid bone
Anterior belly digastric is innervated by
Mylohyoid nerve, a branch of the mandibular nerve, third division of fifth cranial nerve or trigeminal
The posterior belly digastric is innervated by
the posterior digastric nerve, a branch of the seventh cranial nerve (facial nerve)
The mylohyoid muscle is an anterior or posterior suprahyoid muscle?
Anterior
The mylohyoid muscle is located superficial or deep to the digastric muscle?
Deep
• Origin of the mylohyoid muscle
Originates from the mylohyoid line on the medial surface of the mandible
Insertion of the mylohyoid muscle
Inserts into fibrous tissues at the midline of the floor of the mouth - called the mylohyoid raphe;
additionally, the most posterior muscle fibers insert on the body of the hyoid bone
• Action of the mylohyoid muscle
Either elevating the hyoid bone OR depressing the mandible
This muscle also forms the floor of the mouth and helps elevate the tongue
Innervation of the mylohyoid muscle
mylohyoid nerve, a branch of the mandibular nerve (which is a division of the trigeminal nerve)
Thin, posterior suprahyoid muscle that has two slips
Stylohyoid muscle
How many slips does the stylohyoid bone have?
Two
What are the two slips of the stylohyoid muscle?
Superficial slip
Deep slip
Where are the two slips of the stylohyoid muscle?
Located on either side of the intermediate tendon of the digastric muscle
Origin of the stylohyoid muscle
Originates from the styloid process of the temporal bone
Insertion of the stylohyoid muscle
Inserts onto the body of the hyoid bone
Action of the stylohyoid bone:
•Elevates and retracts the hyoid bone
Innervation of stylohyoid muscle
Innervated by the stylohyoid nerve, a branch of the seventh cranial nerve (facial nerve)
Anterior suprahyoid muscle superior to the medial border of the mylohyoid muscle
Geniohyoid muscle
Origin of the geniohyoid muscle?
Originates from the medial surface of the mandible, near the mandibular symphysis at the genial tubercles
Insertion of the geniohyoid muscle
Inserts into the body of the hyoid bone
Action of geniohyoid muscles:
Either elevates and protrudes the hyoid bone OR Depresses the mandible
Innervation of geniohyoid muscle:
Innervated by the first cervical nerve, which is conducted by way of the twelfth cranial nerve (hypoglossal nerve)
Name all the suprahyoid muscles
Digastric
Geniohyoid
Mylohyoid
Stylohyoid
These hyoid muscles are Located inferior to the hyoid bone
Infrahyoid muscles
What are the 4 pairs of infrahyoid muscles?
• Omohyoid muscle
• Sternohyoid muscle
• Sternothyroid muscle
• Thyrohyoid muscle
Action of the infrahyoid muscles?
Most of the infrahyoid muscles depress the hyoid bone; some have specific additional actions
Innervation of the infrahyoid muscles
•All infrahyoid muscles are innervated by the second and third cranial nerves
An infrahyoid muscle lateral to the sternothyroid and thyrohyoid muscles
Omohyoid
The omohyoid muscle has_______that demarcates the subclavian triangle from the occipital triangle within the posterior cervical triangle and divides the inferior portion of the anterior cervical triangle into the carotid triangle and muscular triangle.
two separate bellies:
what are the two bellies of the omohyoid muscle called?
Superior and inferior belly
The superior belly of the omohyoid muscles divides the
inferior portion of the anterior cervical triangle into the carotid triangle and muscular triangle
The Inferior belly of the omohyoid muscle demarcates the
subclavian triangle from the occipital triangle within the posterior cervical triangle
Origin of the omohyoid muscle
Inferior belly originates from the scapula
Superior belly originates from the short tendon attached to the inferior belly
Insertion of omohyoid muscle
Inferior belly attaches to the superior belly; the superior belly inserts into the lateral border of the body of the hyoid bone
Action of the omohyoid muscle
Depresses the hyoid bone
An infrahyoid muscle superficial to the sternothyroid, the thyroid cartilage, and the thyroid gland
Sternohyoid muscle
Origin of sternohyoid muscle
Originates from the posterior and superior surfaces of the sternum, near where the sternum and clavicle join
Insertion of sternohyoid muscle
Inserts into the body of the hyoid bone
Action of the sternohyoid muscle
Depresses the hyoid bone
Does the sternothyroid muscle depress the hyoid?
No, it doesn’t even connect to the hyoid!
An infrahyoid muscle superficial to the thyroid gland. This muscle is not attached to the hyoid bone, which differs from all other hyoid muscles
Sternothyroid muscle
Origin of the sternothyroid muscle
Originates from the posterior surface of the sternum, at the level of the first rib
Insertion of the sternothyroid muscle
Inserts into the thyroid cartilage
Action of sternothyroid muscle
• Depresses the thyroid cartilage and larynx
An infrahyoid muscle deep to the omohyoid and sternohyoid muscles
Thyrohyoid muscle
Origin of thyrohyoid muscle
Originates on the thyroid cartilage
Insertion of thyrohyoid muscle
Inserts on the body and greater cornu of the hyoid bone
Appears as a continuation of the sternothyroid muscle
thyrohyoid muscle
Action of thyrohyoid muscle
Depresses the hyoid bone
Raises the thyroid cartilage and larynx
a thick vascular mass of voluntary muscle surrounded by a mucous membrane that is anchored to the floor of the mouth by the lingual frenum.
The tongue
The tongue has complex movements during mastication, speaking, and swallowing; these movements are a result of the
combined action of muscles of the tongue.
The tongue consists of separate halves divided from each other by the
median septum
What is the Median septum of the tongue?
a deep, tendinous band located within the midline of the tongue
The median septum of the tongue corresponds with the
median lingual sulcus, a midline depression on the dorsal surface of the tongue
The tongue is divided into what three divisions?
base, body and apex
Muscles of the tongue can be grouped according to their
location
Muscles of the tongue can be grouped according to their location. What are the two groups?
Intrinsic group and Extrinsic group
The intrinsic group of muscles of the tongue are located
entirely inside the tongue
The extrinsic group of muscles of the tongue originate on the
outside of the tongue and insert inside the tongue
Both extrinsic and intrinsic groups of the tongue intertwine within
the structure of the tongue
Each half of the tongue has muscular groups within these two main groups (intrinsic and extrinsic), separated by the
Median septum
Action of intrinsic muscles of the tongue
change the shape of the tongue
Action of extrinsic muscles of the tongue
move the tongue, while also suspending the tongue and anchoring it to bony structures of the mandible, the styloid process, and hyoid bone
Innervation of the tongue muscles:
All muscles of the tongue are innervated by the twelfth cranial nerve (hypoglossal nerve)
there are ___pairs of intrinsic tongue muscles
Four
The four pairs of intrinsic muscles of the tongue are grouped and named by their
orientation to the tongue surface
What are the 4 pairs of intrinsic muscles?
Superior longitudinal
Transverse
Vertical
Inferior longitudinal
Because intrinsic muscles are located entirely inside the tongue, do they have origins or insertions outside the body of the tongue?
No
is the most superficial of the intrinsic
muscles
Superior longitudinal muscle
This intrinsic
muscle runs in an oblique and longitudinal direction close to the dorsal surface from the base to the apex
Superior longitudinal muscle
is deep to the superior longitudinal muscle;
Transverse muscle
This intrinsic muscle runs in a transverse direction from median septum to pass outward toward the lateral surface
Transverse muscles
This intrinsic muscle runs in a vertical direction from dorsal surface to the ventral surface in the body of the tongue
Vertical muscle
This intrinsic muscle is close to the ventral surface of the tongue; runs in a longitudinal direction from base to apex
Inferior longitudinal muscle
Action of superior and inferior longitudinal muscles of the tongue are grouped
Superior and inferior longitudinal muscles act together to change the shape of the tongue by shortening and thickening it
When these muscles act independently of one another, it allows the tongue to curl
Action of transverse and vertical muscles of the tongue
Transverse and vertical muscles act together to make the tongue long and narrow
There are ___ pairs of extrinsic muscles of the tongue.
Three
The three pairs of extrinsic tongue muscles are named by
Their location of origin and adding “glossus” to the end (Glossus means “tongue”)
What are the three paired extrinsic muscles of the tongue?
• Styloglossus
• Genioglossus
• Hyoglossus
Origin of all extrinsic tongue muscles
have different origins outside the tongue; beginning of name reveals origin
Insertion of all extrinsic tongue muscles
Insert inside the tongue
Action of all extrinsic muscles of the tongue:
These muscles serve to connect the tongue and move it relative to the three main bony attachments:
• Styloid process with the styloglossus
• Genial tubercles with the genioglossus
• Hyoid bone with the hyoglossus
Innervation of all extrinsic tongue muscles
are innervated by the twelfth cranial nerve (hypoglossal nerve)
The styloglossus muscle is an extrinsic or intrinsic tongue muscle?
An extrinsic tongue muscle
Origin of the styloglossus muscle
Originates from the styloid process of the temporal bone
Insertion of the styloglossus
Inserts into two parts of the lateral surface of the tongue at the border between the body and the base of the tongue and at the apex of the tongue
Action of the styloglossus muscle
Retracts the tongue, moving it superiorly and posteriorly
Largest extrinsic tongue muscle
Genioglossus
Fan-shaped extrinsic muscles located superior to the geniohyoid muscle
Genioglossus
Origin of genioglossus muscle:
Originates from the genial tubercles on the medial surface of the mandible
Insertion of genioglossus muscle
Inserts into the tongue from the base almost to the apex
Action of genioglossus muscle of the tongue:
Protrude or depress parts of the tongue surface
helps to prevent the tongue from sinking back and obstructing respiration
“Stick out your tongue”
The hyoglossus muscle is an intrinsic or extrinsic muscle?
Extrinsic tongue muscle
Origin of hyoglossus muscle:
Originates from both the greater cornu and part of the body of the hyoid bone
Insertion of the hyoglossus muscle
Inserts into the lateral surface of the body of the tongue
Action of the hyoglossus muscle:
Depresses the tongue
What is Ankyloglossia?
a disorder where the lingual frenum (where the tongue is attached to the floor of the mouth) is too short
This is what we call being “tongue tied”
Ankyloglossia
Produces a “heart-shaped”
appearance when one sticks their tongue out
Ankyloglossia
AKA the pharyngeal muscles
Muscles of the pharynx
These muscles are involved in speaking, swallowing, and middle ear function
Muscles of the pharynx
The pharynx is part of both the____tracts, and is connected to both the _____cavities
respiratory and digestive; nasal and oral
The pharynx has what 3 parts
nasopharynx, oropharynx, and laryngopharynx
The pharyngeal muscles include:
Stylopharyngeus
Pharyngeal constrictors
Muscles of the soft palate
Paired longitudinal muscle of the pharynx
Stylopharyngeus muscle
Origin of stylopharyngeus muscle
Originates from the styloid process of the temporal bone
Insertion of the stylopharyngeus muscle
Inserts into the lateral and posterior pharyngeal walls
Action of stylopharyngeus muscle
Elevates and simultaneously widens the pharynx
Innervation of the stylopharyngeus muscle
Innervated by the ninth cranial nerve (glossopharyngeal nerve)
• Form the lateral and posterior walls of the pharynx
Pharyngeal Constrictor Muscles
Consist of 3 paired muscles based on their vertical relationship to the pharynx:
Pharyngeal constrictor muscles
The three paired muscles of the pharyngeal constrictor muscles are
• Superior pharyngeal constrictor muscles
• Middle pharyngeal constrictor muscles
• Inferior pharyngeal constrictor muscles
All 3 of the paired pharyngeal constrictor
muscles originate in different places; the muscles overlap each other and have similar insertions. True or false
True
Superior pharyngeal constrictor muscles originate from the
hamulus of the medial pterygoid plate, pterygomandibular raphe. and mandible
The superior pharyngeal constrictor muscles and the buccinator muscle are attached to each other at the
pterygomandibular raphe
These two muscles are attached to each other at the pterygomandibular raphe
The superior pharyngeal constrictor muscles and the buccinator muscle
Middle pharyngeal constrictor muscles originate on the
hyoid bone and stylohyoid ligament
Stylohyoid ligament runs from the tip
of the styloid process of the temporal bone to the lesser cornu of the hyoid bone
Inferior pharyngeal constrictor muscles originate from
both the thyroid and cricoid cartilage of the larynx
When the pharangeal constrictor muscles overlap, the ______is most superficial
inferior pharyngeal constrictor
Insertion of the pharyngeal constrictor muscles
These muscles all insert into the median pharyngeal raphe
What is the median pharyngeal raphe?
a midline tendinous band of the posterior wall of the pharynx that is itself attached to the base of the skull
Action of the pharyngeal constrictor muscles:
• Raise the pharynx and larynx
• Help drive food inferiorly into the esophagus during swallowing
Innervation of the pharyngeal constrictor muscles
by the pharyngeal plexus
What is the pharyngeal plexus?
A network of nerves that provides sensory and motor innervation to the pharynx
The pharyngeal plexus is located on the
outside of the pharynx
The pharyngeal plexus is made up of contributions from the _____nerves
vagus, glossopharyngeal, and superior cervical
• There are__ paired muscles of the soft palate
five
What are the five paired muscles of the soft palate?
• Palatoglossus muscle
• Palatopharyngeus muscle
• Levator veli palatini muscle
• Tensor veli palatini muscle
• Muscle of the Uvula
The soft palate forms the
nonbony posterior part of the roof of the mouth (oropharynx) and connects laterally with the tongue
All of the soft palate muscles are involved in
Speaking and swallowing
The combined actions of several muscles of the soft palate move the soft palate____
superiorly and posteriorly
Combined actions of several muscles of the soft palate move the soft palate superiorly and posteriorly. This, plus movement of the pharyngeal wall anteriorly creates a separation between the
oropharynx and nasopharynx during swallowing to prevent food from entering the nasal cavity while eating
Innervation of the muscles of the soft palate
• All of the muscles of the soft palate except the tensor veli palatini are innervated by the tenth cranial nerve (vagus nerve) through the pharyngeal plexus
Tensor veli palatini is innervated by the
medial pterygoid nerve, a branch of the mandibular nerve (which is a division of the trigeminal nerve)
Forms the anterior faucial pillar in the oral cavity
Palatoglossus muscle
A vertical fold anterior to each palatine tonsil
Anterior faucial pillar
Origin of palatoglossus muscle:
Originates from the median palatine raphe
What is the median palatine raphe?
Midline tendinous band in the palate
Insertion of palatoglossus muscle
Inserts into the lateral surface of the tongue
Action of palatoglossus muscle
Elevates the base of the tongue, arching the tongue against the soft palate
Depresses the soft palate toward the tongue
This muscle works with others to form a sphincter, closing off the oral cavity from the pharynx
This muscle works with others to form a sphincter, closing off the oral cavity from the pharynx
Palatoglossus
Forms the posterior faucial pillar in the oral cavity
Palatopharyngeus
A vertical fold posterior to each palatine tonsil
Posterior faucial pillar
Origin of palatopharyngeus muscle
Originates in the soft palate
Insertion of the palatopharyngeus muscle
Inserts into the walls of the laryngopharynx and on the thyroid cartilage
Action of palatopharyngeus muscle
Moves both the palate posteriorly and inferiorly and the posterior pharyngeal wall anteriorly and superiorly to help close off the nasopharynx during swallowing
Mainly located superior to the soft palate, name means “lifter of the veil (or curtain)
of the palate”
Levator Veli Palatini Muscle
Origin of Levator Veli Palatini Muscle
Originates in the inferior surface of the temporal bone
Insertion of Levator Vili Palatini muscle
Inserts into the median palatine raphe
Action of levator vili palatini muscle
Raises the soft palate
Helps bring it into contact with the posterior pharyngeal wall to close off the nasopharynx during speech and swallowing
A special, ribbon-like muscle, name means “tension of the veil (or curtain) of the palate”
Tensor Veli Palatini muscle
Origin of tensor veli palatini muscle
Originates in the auditory (pharyngotympanic)
tube and inferior surface of the sphenoid bone
The tensor veli palatini muscle originates in the auditory (pharyngotympanic) tube and inferior surface of the sphenoid bone. This muscle then forms a tendon near the
hamulus of the medial pterygoid plate
How and where is the tension created in the tensor veli palatini muscle?
The muscle originates in the auditory (pharyngotympanic) tube and inferior surface of the sphenoid bone. This muscle then forms a tendon near the hamulus of the medial pterygoid plate. The tendon winds around the hamulus (using it as a pulley) here is where the tension is!
Insertion of the Tensor Veli Palatini Muscle
Inserts into the median palatine raphe
Action of the Tensor Veli Palatini Muscle
Tenses and slightly lowers the soft palate
This muscle is usually active during all palatal movements
Some fibers of this muscle responsible for opening the auditory (pharyngotympanic) tube to allow air to flow between the pharynx and middle ear cavity
A muscle of the soft palate. This muscle lies entirely within the uvula of the palate
Muscles of the uvula
What is the uvula?
a midline tissue that hangs inferiorly from the posterior margin of the soft palate
Action of the Uvula muscles
Shortens and broadens the uvula, which changes the contour of the soft palate
This change in contour allows the soft palate to adapt closely to the posterior pharyngeal wall to help close of the nasopharynx during swallowing
Impairment of the muscles of facial expression, mastication, hyoid muscles, as well as muscles of the tongue, pharynx, and soft palate can critically influence dental treatment because these muscles are_____
involved in speech and swallowing used during the appointment
Etiology of impairments of the muscles of facial expression, mastication, hyoid muscles, as well as muscles of the tongue, pharynx, and soft palate can range from
systemic disease states or syndromes including stroke or cerebrovascular accident) to a genetically determined fault in muscle function such as muscular dystrophy
Strokes on the left side of the brain affect movement on the____
right side of the body and also attack speech function
A patient with impairment of the muscles of facial expression, mastication, hyoid muscles, as well as muscles of the tongue, pharynx, and soft palate may have difficulty
communicating with the dental team such as when answering questions to complete medical/dental histories, and may need assistance from knowledgeable caregivers
The patient may also have difficulty when asked to open the mouth
Some patients with impairment of the muscles of facial expression, mastication, hyoid muscles, as well as muscles of the tongue, pharynx, and soft palate may have difficulty swallowing. This is called
dysphagia
Tardive dyskinesia
refers to abnormal hyperkinetic movements of the muscles of the face, tongue, and neck
Tardive dyskinesia is associated with the use of
neuroleptic agents
Tardive dyskinesia is characterized by
repetitive, involuntary, purposeless movements, such as grimacing, tongue protrusion, lip smacking, puckering and pursing of the lips, and rapid eye blinking
