Muscles of Mastication Flashcards
_____ ANATOMY or oral cavity includes ▪DENTITION AND SUPPORTIVE STRUCTURES▪SKELETAL COMPONENTS▪TEMPOROMANDIBULAR JOINTS a.k.a. the TMJ▪LIGAMENTS▪MUSCLES
Functional Anatomy
What bones are involved in TMJ?
Temporal and mandible
2 MAXILLARY BONES are FUSED TOGETHER AT THE ________
MID-PALATAL SUTURE
____ border of maxilla makes up the FLOOR OF THE NASAL CAVITY AND ORBIT
Superior border of maxilla
____ border of maxilla makes up the PALATE AND ALVEOLAR RIDGE
Inferior border of maxilla
What are the 4 processes of the maxilla?
Zygomatic, frontal, alveolar, palatine
_______ extends from the incisive papilla to the distal end of the hard palate. The overlying mucosa is tightly attached and thin. Relief is usually required to prevent soreness. The underlying bone is dense and often raised forming a torus palatinus
Midline palatal suture-
______ the orifice of the anterior palatine nerve and blood vessels. Relief in this area is usually not required due to the abundant overlying tissues
Major palatine foramen-
_____ aspect of the mandible includes Alveolar crest and Teeth
SUPERIOR ASPECT
____ aspect of the mandible includes Mandibular Angle, Ascending Ramus, Coronoid process, and Condyle
Body/Posterior Aspect
_________ is a ridge of dense bone from the mental foramen, coursing superiorly and distally to become continuous with the anterior region of the ramus. This line is the attachment site of the buccinator muscle and an anatomic guide for the lateral termination of the buccal flange of the mandibular denture
External Oblique Line
the anterior exit of the mandibular canal and the inferior alveolar nerve. In cases of severe residual ridge resorption, the foramen occupies a more superior position on then ridge and the denture base must be relieved to prevent nerve compression and pain
Mental Foramen
______ states that bone in a healthy person or animal will adapt to the loads under which it is placed.
Wolff’s law
Part of the mandible that articulates with the cranium; contains medial and lateral poles
Condyle
Squamous portion articulates the mandibular condyle; contains ARTICULAR or GLENOID FOSSA
Temporal bone
_____ is Thick dense bone to tolerate heavy forces
ARTICULAR EMINENCE –
____ head of the masseter has fibers that run down and back
Superificial
____ head of the masseter has fibers that run in a vertical direction
deep
What muscle is this?
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Masseter
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Origin of the ____ muscle includes: Anterior 2/3 of the lower border of ZYGOMATICH ARCH; medial surface of zygomatic arch
Masseter
Insertion of the ____ muscle includes: LATERAL SURFACE OF RAMUS andANGLE OF THE MANDIBLE
Masseter
_____ muscle elevates the mandible that is a powerful muscle providing the force for chewing
Masseter
____ head of the masseter aids in protrusion
Superficial head of masseter
_____ head of masseter STABILIZES THE CONDYLE AGAINST THE EMINENCE
Deep head of masseter
Origin of _____ muscle: TEMPORAL FOSSA and LATERAL SURFACE OF THE SKULL
Temporalis
Insertion of _____ muscle: CORONOID PROCESS and ANTERIOR BORDER OF ASCENDING RAMUS
Temporalis
_____ portion of Temporalis contain vertical directed fibers
Anterior
_____ portion of Temporalis contain fibers running obliquely across the lateral aspect of the skull
Middle
_____ portion of Temporalis contain horizontal fibers come forward above the ear to join other fibers
Posterior
What muscle is this?
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Temporalis
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_____ nerve runs thru the mandibular foramen
Alveolar nerve
_____ muscle raises mandible vertically, elevates and retrudes the mandible, and aids in retrusion of the mandible
Temporalis
____ portion of the temporalis where MANDIBLE IS RAISED VERTICALLY
ANTERIOR TEMPORALIS
____ portion of the temporalis ELEVATES AND RETRUDES THE MANDIBLE
MIDDLE TEMPORALIS
_____ portion of the temporalis AIDS IN RETRUSION OF THE MANDIBLE
Posterior temporalis
What muscle is this?
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Lateral Pterygoid
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Origin of ____ muscle is outer surface of the lateral pterygoid plate
Lateral pterygoid
Insertion of ______ muscle is the neck of the condyle
Inferior Lateral Pterygoid
_____ muscle extends back, up and out
Inferior lateral Pterygoid
BILATERAL CONTRACTION of ____ muscle Causes the condyles to be pulled down the articular eminences and the mandible is protruded
Inferior Lateral Pterygoid
UNILATERAL CONTRACTION of ____ muscle Causes mediotrusivemovement (downward, forward, and medially)
Inferior Lateral Pterygoid
Origin of ____ muscle: infratemporal surface of the greater sphenoid wing, lateral wall of the pterygoid plate
Superior lateral pterygoid
Insertion of ____ muscle: disk, capsule, and neck of the condyle
Superior lateral pterygoid
____ muscle is Inactive during mandibular opening; Active only with elevator muscles (closure of the mandible)
Superior lateral pterygoid
____ muscle is active during the power stroke: this muscle is active during mandibular closure against resistance (chewing or clenching), positions the disc against the articular eminence
Superior lateral pterygoid
Origin of ___ muscle: Inferior Head, on the lateral surface of the lateral pterygoid plate of the sphenoid bone
Inferior Lateral Pterygoid
Insertion of _____ muscle: The two heads fuse into one mass, but fibers of the superior head insert into the capsule and through it indirectly onto the anterior surface of the articular disk. The remaining fibers insert below the capsule into the anterior (medial) surface of the mandible neck in a triangular area
Inferior Lateral Pterygoid
____ movement of the mandible will move the coronoid process toward the maxilla
Lateral movement
Origin of ____ muscle: terygoid fossa, medial surface of the pterygoid plate
Medial Pterygoid
Insertion of _____ muscle: medial surface of the mandibular angle
Medial Pterygoid
What muscle is this?
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Medial Pterygoid
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____ muscle ELEVATES the mandible, PROTRUDES the mandible, UNILATERAL contraction results in mediotrusion
Medial Pterygoid
What 2 muscles make up the masseter sling?
Masseter and Medial Pterygoid
Which muscles close the mandible together?
Masseter and Medial Pterygoid
What are the 2 soft palate depressors?
Palatoglossus and Palatopharyngeal
Are the soft palate depressors attached to bone?
No
What are the 3 soft palate elevators?
Tensor veli palatini, levator veli palatini, and Musculus uvulae
_____ muscles close off oropharynx from nasopharynx
Soft palate elevators
Are the soft palate elevators attached to bone?
Yes
_______ consists of the junction between the superior constrictor and the buccinator muscles. It forms part of the retromolar pad
Pterygomandibular raphe
What 2 muscles make up the pterygomandibular raphe?
Superior constrictor and buccinator
the action of the masseter muscle reflects the buccinatormuscle in a superior and medial direction. The distobuccal flange of the denture should be contoured to allow freedom for this action otherwise the denture will be displacedor the patient will experience soreness in this area.
Masseter Groove
The _____ muscle arises from the outer surfaces of the alveolar processes of the maxilla and mandible,corresponding to the three pairs of molar teeth; and behind, from the anterior border of the pterygomandibularraphéwhich separates it from the superorconstrictor.
buccinator
where the buccinatorand superior constrictor connect; Extends from the pterygoidhamulussuperiorly to the alveolar ridge inferiorly under the retromolar gland
Pterygomandibular raphe
The muscles that form the sides, entrance, and floor of the oral cavity are the _____, _____, and ______
buccinators, orbicularis oris, and mylohyoids
The parts of ____ muscle arise from the lower third of the posterior margin of the medial pterygoidplate and its hamulus(Pterygopharyngealpart); from the pterygomandibularraphe (Buccopharyngealpart); from the alveolar process of the mandible above the posterior end of the mylohyoid line(Myolopharyngealpart); and by a few fibers from the side of the tongue (Glossopharyngeal part)
Superior Constrictor
What muscles comprise the suprahyoid group?
GENIOHYOID, MYLOHYOID, DIGASTRIC, and STYLOHYOID
_____ muscles ELEVATE HYOID BONE and DEPRESS THE MANDIBLE WHEN HYOID BONE IS FIXED
Suprahyoids
Origin of ____ muscle: Inferior genial tubercle on the inner surface of mandibular symphysis
Geniohyoid
Insertion of _____ muscle: Anterior surface of body of hyoid bone
Geniohyoid
What is this group of muscles called?
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Suprahyoids
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Origin of _____ muscle: LINE FROM LAST MOLAR ROOT TO MANDIBULAR SYMPHYSIS
Mylohyoid
Insertion of ____ muscle: MEDIAN RAPHE FROM CHIN TO HYOID BONE
Mylohyoid
_____ muscle forms the muscular floor of the mouth. Arises from the ____ ridge of the mandible. Determines the lingual flange extension of the denture. Ends at about thefirst molar area.
Mylohyoid muscle; Mylohyoid ridge
_______ is present on the lingual surface of the anterior mandible and serve as the attachment sites of the genioglossusand geniohyoidmuscles of the tongue. In patients with severe ridge resorption (see R photo), the geniotuberclesmay cause discomfort if they are more exposed to the denture base.
Geniotubercle (Mental Spines)
Origin of ____ muscle: The posterior belly, longer than the anterior, arises from the mastoid process▪The anterior belly arises from a depression on the inner side of the lower border of the mandible, close to the symphysis
Digastric Muscle
Insertion of ____ muscle: hyoid bone
Digastric muscle
Origin of ____ muscle: posterior border of styloid process
Stylohyoid muscle
Insertion of ____ muscle: hyoid bone
Stylohyoid muscle
Oris orbicularis, Zygomatic Major and Minor, Risorius, and Levator Labii superioris make up the ____ muscles of the mouth
Maxillary
Oris orbicularis, Depressor labii (inferior), Mentalis,Depressor angularis, and Risorius make up ____ muscles of the mouth
Mandibular
What are the 4 muscles of facial expression?
Modiolus, Buccinator, Mentalis, and Orbicularis oris
Do the muscles of facial expression insert in bone?
No
_____ is at the corner of the mouth
Modiolus
______ is a concentration of several muscle groups and is situated laterally and slightly superiorly to the corner of the mouth. This is an area where extrinsic perioral muscles join intrinsic fibers of the orbicularis orismuscle. It is a very forceful area which can influence the labial flange thickness of the maxillary denture.
Modiolus
_____ muscle provides support and mobility of the soft tissues of the cheek. The muscle fibers contract in a line parallel to the plane of occlusion. As people age, tension is lost in this muscle which predisposes a patient to cheek biting (espwith a new denture). The masseter often exerts it’sforce through this muscle
Buccinator
This muscle and associated fat pad, can be an interference when prepping 2ndmolars for a crown.
Buccinator
______ elevates the skin of the chin and turns the lower lip outward. Dictates the length and thickness of the labial flange extension of the lower denture.With the severely resorbed mandible, this muscle will lose it’s attachment.
Mentalis
Origin of ___ muscle: incisive fossa of the mandible
Mentalis
Insertion of ____ muscle: soft tissue of the lower lip
Mentalis
_______ is the sphincter muscle of the mouth. It has no skeletal attachmentsand is composed of many muscles that converge at the modiolus.
Orbicularis Oris
The muscles of facial expression are all innervated by ______
Facial Nerve (CN VII)
Muscles of _____ these muscles assist with the functions of chewing, swallowing, and speaking. Any deficiency may create problems with these actions, andmay create difficulties with wearing a dental prosthesis.
Facial Expression
The modiolus is a chiasma of facial muscles held together by ______, located lateral and slightly superior to each angle of the mouth. It is important in moving the mouth, facial expression and in dentistry.
fibrous tissue
When the _____. muscle contracts, the lips close
Orbicularis oris
The ______ muscle has no real bony origin. Instead, it is entirely rimmed by the insertions of other muscles of facial expression, most of which do originate on bone.
orbicularis oris
Origin: Height of zygomatic bone just anterior to the zygomaticus major
Insertion: Corner of the mouth
Zygomaticus Major
The _______ muscle is oblong, flat, and cylindrical. It is positioned lateral to and above the angle of the mouth. It originates at the zygomatic bone, lateral to the levatorlabii superioris muscle, and inserts in skin just superior to and at the angle of the mouth.
zygomaticus major
The _____ muscle’s action is to draw the angle of the mouth laterally and upward.
Zygomaticus Major
_____ muscle is medial to zygomaticus major and elevates corner of mouth
Zygomaticus minor
Origin: frontal process of the maxilla
Insertion: Skin of the wing of the nose.
Levator Labii Superioris alaeque nasi LLSAN
_____ muscle acts to elevate the upper lip, widen the nasal opening, and raise the corner of the mouth
Levator Labii superioris LLS
O –a line paralleling the infraorbital margin
I -skin of the lip just below the nasolabial sulcus as far as the vermilion border
Levator Labii superioris LLS
____. muscle acts to draw the angle of the mouth downward
Depressor anguli oris DAO
O –lower border of the lateral body of the mandible just above platysma
I –The modiolus at the corner of the mouth
Depressor anguli oris DAO
____ muscle depresses and inverts the lower lip
Depressor labii inferioris DLI
O –On the lateral body of the mandible, just above the depressor angulioris
I –by tiers to the skin above the mentolabialfold
Depressor labii Inferioris DLI
O –On the lateral body of the mandible, just above the depressor anguli oris
I –Risorius, and orbicularis oris, modiolus
Depressor angular oris DAO
_____ muscle draws the angle of the mouth downward and laterally
Depressor angular oris DAO
____ muscle tightens lower lip and moves lip down
Mentalis
O –forms a circular area that extends from the central incisor to the canine eminence, on the anterior lateral mandible
I –Into the skin, the chin and the lip
Mentalis
O –labial border of the mandible
I–into the lower lip
Depressor labii inferioris
To depress the mandible, what muscles must contract?
INFERIOR LATERAL PTERYGOIDS and DIGASTRIC
To depress the mandible, what muscles must relax?
MASSETERS, MEDIAL PTERYGOIDS, and TEMPORALIS
What muscles must contract to elevate mandible?
MASSETERS, MEDIAL PTERYGOID, TEMPORALIS, and SUPERIOR LATERAL PTERYGOID
What muscles must relax to elevate the mandible?
INFERIOR LATERAL PTERYGOID and DIGASTRIC
What muscles must contract to allow right lateral movement of mandible?
Left inferior lateral pterygoid
What muscle must relax to allow right lateral movement?
Right Inferior Lateral Pterygoid and Slightly elevators
Protrustion of the mandible is caused by the contraction of what muscles?
Inferior lateral pterygoids
What muscles assist in contraction to protrude the mandible?
Masseters and medial pterygoid
What muscles contracts to retrude the mandible?
Temporalis