test 2 Flashcards
Classification of muscle tissue
Skeletal - voluntary
Smooth - involuntary
Cardiac - Involuntary
what is the difference between voluntary and involuntary muscles
voluntary - we control it
involuntary - not consciously controlled, body controls it
Why do we study the muscles 3
Extra oral patient exams
Distinguish normal/abnormal
Understand source of muscle pain/loss of function
define origin and insertion
origin: Part of the muscle that does not move
insertion: attached to the more moveable structure
define belly
thicker, middle region of muscle between origin and insertion; located between 2 ends
define innervation
the supply of nerves to a specific body part; one to one relationship
what are the muscle groups
-Cervical muscles
-Muscles of facial expression
-Muscles of mastication
-Hyoid muscles (Suprahyoids and infrahyoids)
-Muscles of the tongue (Extrinsic and intrinsic muscles)
what are the clinical considerations for occlusal trauma 2
abfraction: loss of tooth structure at the cervical area (where tooth and gum meet)
attrition: gradual wear and loss of tooth structure due to the mechanical forces of chewing and grinding (tooth to tooth contact)
what are the cervical muscles
sternocleidomastoid and trapezius
sternocleidomastoid
origin
insertion
bellies
action
origin- clavicle and sternum
insertion- mastoid process of temporal and occipital bone
bellies- none
action- bends head to the side that contracts, flexes neck when both contract
trapezius
origin
insertion
bellies
action
origin - external surface of occipital bone; midline of cervical and thoracic regions
insertion - clavicle and scapula
bellies - none
action - lift clavicle and scapula when shoulders are shrugged
clinical considerations of cervical muscles 5
- muscle malfunction may cause head to move to one side or the other
- may not be able to raise chin during treatment
- may not be able to sit in ergonomically correct position
- usually from acute trauma such as vehicle/sport accidents or chronic stress via movement
- possibly related with headaches in lower skull region
describe muscles of facial expression
- paired
- all origins originate from surface of the skull bone (rarely the fascia)
- all insert on dermis of the skin
clinical considerations for muscles of facial expression
- Facial paralysis: damage to CNVII; inhibits muscle movement on the side of nerve damage; loss of voluntary muscle action; temporary or permanent; can occur with stroke, bell palsy, or parotid salivary gland cancer; twitching/spasms/weakness may resolve over time
- facial nerve within the parotid salivary gland can become anesthetized with an incorrectly administered inferior alveolar mandibular block leading to transient facial paralysis
epicranial muscle
origin
insertion
bellies
action
expression
origin - frontal belly originates at epicranial aponeurosis; occipital belly originates at occipital and temporal bones
insertion - frontal belly inserts at the eyebrow and root of the nose; occipital belly inserts at the epicranial aponeurosis
bellies - 2: frontal and occipital bellies separated by the epicranial aponeurosis
action - raise the eyebrows and scalp; the two bellies can act independently from eachother
expression - surprise
orbicularis oculi muscle
origin
insertion
bellies
action
expression
origin - orbital rim, frontal bone, and maxilla
insertion - lateral canthus
bellies - none
action - closes the eyelid, squints (crows feet)
expression - closing eye/ squint
orbicularis oris
origin
insertion
bellies
action/expression
origin - facial modiolus
insertion - labial commissure > diffusely in lip/nose; upper lip
bellies - none
action/expression - closing/pursing lips; pouting; grimacing; speech; press; tighten/thin; roll inward; thrust outward
buccinator
origin
insertion
bellies
action
origin - maxilla, mandible, pterygomandibular raphe
insertion - labial commissure (facial modiolus)
bellies - none
action/expression - compresses cheeks during chewing; pulls labial commissure laterally; shortens cheek vertically and horizontally; assists muscles of mastication
*pierced by parotid duct
risorius
origin
insertion
bellies
action
origin - fascia superficial to masseter muscle
insertion - labial commissure at facial modiolus
bellies - none
action/expression - stretches lips; widens mouth; stretches labial commissure laterally; grimace
*often underdeveloped, connected with platysma that stretches with it
levator labii superioris
origin
insertion
bellies
action
origin - maxilla
insertion - labial commissure of upper lip
bellies - none
action/expression - raises upper lip
levator labii superioris alaeque nasi
origin - maxilla
insertion - ala of nose; upper lip
bellies - none
action - raising upper lip and dilating/raises ala/nares with sneer/snarl
*Elvis muscle
zygomaticus major
origin - zygomatic bone
insertion - labial commissure
bellies - none
action/expression - smiling; elevates labial commissure laterally
*lateral to zygomaticus minor; genuine happiness is expressed when this muscles contracts WITH the orbicularis oculi
zygomaticus minor
origin - zygomatic bone
insertion - upper lip
bellies - none
action/expression - raising upper lip to assist in smile
*adjacent to insertion of levator labii superioris
levator anguli oris
origin - maxilla (canine fossa)
insertion - labial commissure
bellies
action/expression - assist in smiling, raises labial commissure
- deep to zygomaticus major and minor; connects with zygomaticus major, depressor anguli oris and orbicularis oris
depressor anguli oris
origin- inferior border of mandible
insertion - labial commissure
bellies - none
action/expression - frowning, lowers labial commissure
depressor labii inferioris
origin - inferior border of mandible
insertion - lower lip
bellies - none
action/expression - depresses lower lip; exposes canines
*deep to depressor anguli oris
mentalis
origin - mandible
insertion - chin
bellies
action/expression - raises chin, protrudes lower lip, “peach pit dimple”
*could dislodge a complete lower denture in an edentulous patient who lost alveolar process height
platysma
origin - clavicle; shoulder
insertion - mandible; muscles of mouth; facial modiolus
bellies
action/expression - raises neck skin; assist in grimace by pulling labial commissures down; horror/disgust
- creates platysma bands with age (turkey neck)
corrugator supercilii muscle
origin
insertion
bellies
action
expression
origin - supraorbital region of frontal bone
insertion - skin above the eyebrow
bellies - none
action - draws eyebrow inferiorly and medially
expression - anger/frowning
- chemodenervation to alleviate glabellar/frown lines (botox)
describe the muscles of mastication 6
- four paired muscles
- deep to muscles of facial expression
- all connect to the mandible at some point
- masseter, temporalis, medial and lateral pterygoid muscles
- may be involved w pathology associated with TMJ
- embryonic derivatives of first branchial/mandibular arch
masseter
origin
insertion
bellies
action
clinical consideration
origin - zygomatic arch
insertion - angle and ramus of mandible
bellies/heads - 2 heads, superficial and deep head
action - during bilateral contraction it elevates the mandible
masseteric hypertrophy
*most powerful and superficial muscle of mastication
what is masseteric hypertrophy 6
- enlargement of masseter muscle
- caused by clenching/grinding/bruxism/gum chewing
- asymptomatic, slightly firm when palpated
- usually bilateral, can be unilateral
- may be confused with dental infections and other diseases; however no symptoms of tenderness or pain are present
- may be associated with TMJ pathology
temporalis
origin
insertion
bellies
action
origin - temporal fossa
insertion - coronoid process of the mandible ramus
bellies - none
action - maintains mandible in rest position, allows freeway space, bilateral contraction of entire muscle raises mandible; bilateral contraction of posterior portion retracts/retrudes mandible
medial pterygoid
origin
insertion
bellies
action
origin - Deep head: medial side of lateral pterygoid plate and pterygoid fossa of sphenoid Superficial head: maxillary tuberosity and palatine bone
insertion - both onto medial surface of mandibular angle/ramus
bellies - 2 heads
action - bilateral contraction elevates mandible
*works with masseter
lateral pterygoid
origin
insertion
bellies
action
origin - superior head: infratemporal crest of greater wing of sphenoid bone. inferior head: lateral side of lateral pterygoid plate
insertion - anterior surface of neck of mandibular condyle
bellies - none
action - unilateral contraction shifts mandible to opposite side (lateral deviation); bilateral contraction protrudes* mandible forward and depresses* when opening
*fills in temporal fossa
what are the suprahyoid muscles
digastric
mylohyoid
stylohyoid
geniohyoid
what are the infrahyoid muscles
omohyoid
sternohyoid
sternothyroid
thyrohyoid
what is the action of the suprahyoids
- elevate the hyoid and larynx
- occurs during swallowing
- contraction of anterior suprahyoids depresses the mandible
what muscles are apart of the anterior group for suprahyoids
digastric (anterior belly)
mylohyoid
geniohyoid
what muscles are apart of the posterior group for suprahyoids
digastric (posterior belly)
stylohyoid
digastric muscle
origin
insertion
bellies
action
anterior or posterior/ supra or infra
origin - anterior belly: intermediate tendon. posterior belly: mastoid notch of temporal bone
insertion - anterior belly: digastric fossa (medial surface of mandible). posterior belly: intermediate tendon
bellies: anterior and posterior
action: elevates hyoid bone or depresses mandible
both; anterior belly and posterior belly; suprahyoid
mylohyoid muscle
origin
insertion
bellies
action
anterior or posterior/ supra or infra
origin - mylohyoid line (medial surface of mandible)
insertion - mylohyoid raphe and body of hyoid bone
bellies - none
action - elevates hyoid, depresses mandible, forms floor of mouth and elevates tongue
anterior; suprahyoid
stylohyoid muscle
origin
insertion
bellies
action
anterior or posterior/ supra or infra
origin - styloid process
insertion - body of the hyoid bone
bellies - none
action - elevates and retracts hyoid bone
posterior; supra
geniohyoid muscle
origin
insertion
bellies
action
anterior/posterior; supra/infra
origin - genial tubercles
insertion - body of hyoid bone
bellies - none
action - elevates or protrudes hyoid bone; depresses the mandible
anterior; supra
general description of the infrahyoid muscles
- 4 paired muscles
- inferior to hyoid
- depress hyoid bone
omohyoid
origin
insertion
bellies
action
supra or infra
origin - inferior belly: scapula. superior belly: short tendon attached to inferior belly
insertion - inferior belly: short tendon to superior belly. Superior belly: lateral border of hyoid bone
bellies - superior and inferior belly
action - depresses hyoid bone
infra
sternohyoid muscle
origin
insertion
bellies
action
supra or infra
origin - sternum and clavicle
insertion - body of hyoid bone
bellies - none
action - depresses hyoid bone
infra
sternothyroid muscle
origin
insertion
bellies
action
supra or infra
origin - sternum and first rib
insertion - thyroid cartilage
bellies - none
action - depresses thyroid cartilage and larynx (doesn’t directly depress hyoid bone)
infra
*only hyoid muscle that doesn’t connect to hyoid bone
thyrohyoid muscle
origin
insertion
bellies
action
supra or infra
origin - thyroid cartilage
insertion - body and greater cornu of hyoid
bellies - none
action - depresses hyoid, raises thyroid and larynx
infra
what are the intrinsic muscles of the tongue
located entirely inside the tongue
superior longitudinal (most superficial); transverse; vertical; inferior longitudinal (close to ventral surface)
superior longitudinal muscle
origin/ insertion
action
direction of muscle
origin/insertion - n/a (inside the tongue)
action - curls tongue superiorly; shortens and thickens tongue; works w inferior long. muscle
direction of muscle - runs oblique and longitudinal on the dorsal surface from base to apex
transverse muscle
origin/ insertion
action
direction of muscle
origin/ insertion - n/a (inside the tongue)
action - narrows and elongates tongue
direction of muscle - transverse direction from median septum outwardly toward lateral surface of tongue
vertical muscle
origin/ insertion
action
direction of muscle
origin/ insertion - n/a (inside the tongue)
action - flattens and broadens the tongue or both lengthens and narrows the tongue
direction of muscle - runs from dorsal surface to ventral surface of tongue body
inferior longitudinal muscle
origin/ insertion
action
direction of muscle
origin/ insertion - n/a (inside the tongue)
action - curls the tongue superiorly or both shortens and thickens the tongue (works with superior)
direction of muscle - runs in a longitudinal direction on the ventral surface from base to apex
what is the medium septum
- also called lingual septum
- vertical layer of fibrous tissue
- extends through entire length of median plane of tongue
- deep to the superficial median sulcus (learned in surface anatomy)
what are the extrinsic tongue muscles
styloglossus
genioglossus
hyoglossus
styloglossus muscle
origin
insertion
action
origin - styloid process of temporal bone
insertion - tongue
action - retracts tongue
genioglossus muscle
origin
insertion
action
origin - genial tubercles (medial surface of mandible)
insertion - hyoid bone and tongue
action - protrudes tongue and depresses parts of it
hyoglossus
origin
insertion
action
origin - greater cornu and body of hyoid bone
insertion - tongue
action - depresses tongue
clinical considerations with impaired muscles
- impairment of all these muscles can alter dental treatment because they are involved in speech and swallowing
- strokes on the left side of the brain impact muscles on the right side and vice versa
- dysphagia, mouth droop
- may need extra dental suctioning to prevent choking
- active tongues may need a mouth prop or relaxant
- patience and adaptability are key factors
what is dysphagia
difficultly swallowing
what is mouth droop
inability to close the mouth
which cranial nerve innervates the TMJ
mandibular branch of the trigeminal nerve (CN V)
cranial nerve five
define joint
where is the TMJ located generally
what are the articulations of the TMJ (general)
what nerve innervates it
joint- site of junction/union between TWO BONES
both sides of the head
mandibular condyle articulates with temporal bone
trigeminal nerve (mandibular branch)
what does the articulating portion of the temporal bone include 3
- articular eminence: smooth rounded ridge that is ramp shaped
- articular fossa: (glenoid fossa) posterior to articular eminence; oval shaped depression (actually articulating
- post glenoid process: posterior to articular fossa
direction of the condyle
strongly convex anteroposteriorly; slightly convex mediolaterally
describe the joint capsule 3
- fibrous joint capsule completely encloses the TMJ
- Superiorly: wraps around the temporal bone’s articular eminence and articular fossa
- Inferiorly: wraps around the mandibular condyle and neck
describe the joint disc (6)
- Located between the temporal bone and mandibular condyle; allowing articulation
- attached to the lateral and medial poles of the mandibular condyle; not free; indirectly attached to the temporal bone through the capsule
- shape conforms to adjacent articulating bones
- Divides the TMJ into 2 synovial cavities; both lined with membranes that produce clear viscous synovial fluid (upper and lower division)
- Disc can develop calcifications, be dislocated forward by injury to the posterior attachment, or can become thin/perforated during aging
- attached to post glenoid process in upper division and neck of the condyle in lower division by an ELASTIC LAMINA
what are the two areas/divisions of the joint disc 3
- Upper Division of the posterior part of the disc: attached to the temporal bone at the post-glenoid process
- Lower division of posterior part: attached at the neck of the condyle; where nerves and blood vessels enter the joint
- disc blends with the capsule at these points
- attached by elastic lamina
the ______ is vascularized and innervated
the _____ area of the disc is avascular
periphery; central
define ligament
band of fibrous tissue that connects bones
what 3 ligaments are associated with the TMJ
- temporomandibular ligament *
- stylomandibular ligament
- sphenomandibular ligament
describe the temporomandibular ligament 4
-formed on lateral side of each TMJ forming a reinforcement of the lateral part of the joint capsule
-base attached to the zygomatic process of temporal bone
-apex attached to the lateral side of the neck of the condyle
-prevents excessive retraction or backward movement of the mandible
describe stylomandibular ligament 3
-runs from the styloid process of the temporal bone to the angle of the mandible
-separates the parotid and submandibular salivary glands. don’t remember this
-becomes tight when the mandible is protruded
describe the sphenomandibular ligament 4
-long band on the medial surface of the mandible runs from the angular spine of the sphenoid bone to the lingula which is near where the inferior alveolar nerve enters the medial aspect of the body of the mandible
-although not part of the TMJ it becomes tight when the mandible is protruded
*-is a landmark used for the inferior alveolar nerve block which anesthetizes the mandibular teeth
*- if not penetrated during the injection, it may prevent anesthesia
what are the two basic movements of the TMJ
1.Gliding
- Allows the jaw to protrude (go forward) and retract (go backward)
- Aids in depression of the mandible (opening) and elevation of the mandible (closing)
- Aids in lateral movements
- occurs between disc and articular eminence in upper synovial cavity
2.Rotating-
- Aids opening and closing (depression&protrusion/elevation&retraction)
- Aids in lateral movements
- (chewing)
- occurs between disc and condyle in lower synovial cavity
what muscles are responsible for protrusion and retraction in terms of “gliding”
Protrusion- bilateral contraction of lateral pterygoids
Retraction- bilateral posterior portions of the temporalis muscles
combination of gliding and rotation allows____
- opening, closing, and lateral movements
- opening: depression and protrusion
- closing: elevation and retraction
lateral deviation: unilateral TMJ movement
- Involves gliding and rotational movements
- One disc/condyle glides forward and medially on the articular eminence in the upper synovial cavity while the other disc on the opposite side remains stable
- Move jaw to left, right lateral pterygoid moves the right condyle/disc forward while the left side remains stable
- Causing rotation around the stable joint
anterior suprahyoid muscles are involved in _________ the mandible
depressing the mandible when they bilaterally contract
protrusion of the mandible moving forward
- what temporomandibular joint movements are involved
- what are the associated muscles
- gliding in both upper synovial cavities
- lateral pterygoid with bilateral contraction
retraction of mandible moving backward
- what temporomandibular joint movements are involved
- what are the associated muscles
- gliding in both upper synovial cavities
- posterior part of temporalis and/or suprahyoids with bilateral contraction
elevation and retraction; closing jaw
- what temporomandibular joint movements are involved
- what are the associated muscles
- gliding in both upper synovial cavities with rotation in both lower synovial cavities
- masseter, temporalis, medial pterygoid with bilateral contraction
depression and protrusion of mandible; open jaw
- what temporomandibular joint movements are involved
- what are the associated muscles
- gliding in both upper synovial cavities with rotation in both lower synovial cavities
- suprahyoids and lateral pterygoid with bilateral contraction
lateral deviation of mandible; shifting to one side
- what temporomandibular joint movements are involved
- what are the associated muscles
- gliding in one upper synovial cavity while the condyle and disc of other side spin around approx. vertical axis within upper synovial cavity
- lateral pterygoid with unilateral contraction
rest position of the mandible
- interocclusal clearance/ freeway space
- 2-4 mm between opposing teeth
- joint disc is in upper most posterior portion of articular fossa
- resting is not with the teeth biting together
palpation of TMJ
- feel anterior to EAM bilaterally
- patient should open and close while feeling
- patient should move laterally left/right w jaw
- repeat with fingers IN the EAM bilaterally
clinical considerations with TMJ
temporomandibular disorder
sublaxation > lock jaw
trismus > reduced opening of the jaw
what is TMD 4
- can be cause by 30 different conditions
- 2x more common in women (ages 35-44) textbook says 20-40 years of age
- can be seen alone or in combination with other disorders such as sleep dysfunction, chronic headaches, and irritable bowel diseases
- 11-12 million adults experience pain in that region
what are the 3 main categories of TMD disorders, explain them
1.Myofascial Pain
- the most common disorder
- Internal Derangement of the Joint
- Displaced Disc
- Dislocated Jaw
- Injury to the condyle - Arthritis-degenerative/inflammatory disorders
- can include osteo or rheumatoid arthritis
t/f just because you have jaw clicking doesnt mean you have TMD
true: 40-60% of people experience jaw clicking/popping without TMD
TMD causes
Trauma:
- Macrotrauma- car accident or injury
- Microtrauma- parafunctional habits like bruxism (more common)
Disease:
Osteoarthritis
what is subluxation (slides)
- can occur in some patients when they open too wide and are stuck open
- Due to the head of the condyle moving too far anteriorly on the articular eminence
- Can be treated by carefully moving the
mandible downward and backward
*lock jaw
what is limited opening
- TMD produces a limited opening of the mandible and
make treatment very challenging - Patients with a history of TMD may require the use of a bite block to gently hold the mandible open during
appointments - Limit appointment times with patients who have a history of TMD
symptoms of TMD
- Radiating pain in face , neck, or jaws
- Jaw muscle stiffness
- Limited opening or locking of jaw
- Painful clicking , popping or grating in the joint when
opening or closing - Change in bite: Research does not support the belief that a bad bite or orthodontic braces cause TMDs.
assessment of TMD
physical assessment (questionaire) > then Psychosocial assessment (assesses their pain)
conservative/reversible TMD treatments
- Soft foods/Ice pack
- Avoid yawning, gum chewing or loud yelling
- Stretching exercises
- Stress reduction- Psychological Therapy
- Behavior modification- biofeedback, meditation
- Exercise and Diet modification-decrease caffeine and nicotine before bedtime
- Stabilization splints—rigid not soft splint to prevent tooth destruction
- Splints used primarily to prevent destruction of tooth
structure > still should address underlying causes - Physical therapy and exercise-stretching and posture
- Therapeutic Injections/Acupuncture- Trigger Point injection
- Pharmacologic Therapy –NSAIDS, tricyclics and SSRIs, muscle relaxants
Irreversible Procedures for TMD
Joint Surgery- usually as a last resort
Botox-does not help with TMD
