What is the end of the muscle that is attached to the least moveable structure?
What is the end of the muscle that is attached to the more moveable structure?
What is the movement accomplished by a muscle when the muscle fibers contract?
Elevation, depression, protrusion, retursion, and lateral movements
What are the 5 primary jaw movements?
5th cranial/ trigeminal
All muscles of mastication are innervated by what nerve?
Masseter, medial pterygoid, lateral pterygoid, and temporalis
What are the 4 main pairs of muscles of mastication?
Masseters, medial pterygoid, and temporalis
What 3 pairs of muscle are responsible for the elevation of the mandible?
Masseter and medial pterygoid
What muscles form a sling around the angle of the mandible?
What muscle pair is responsible for protrusion of the mandible?
What muscle pair is responsible for retrustion of the mandible?
Insertions of some fibers of what muscle extend into the TMJ capsule and to the articular disc?
Lateral pterygoid, digastric, and other suprahyoid muscles
What muscles are responsible for depression of the mandible?
Which muscles consists of 2 bellies?
Elevator, retrudor, and protrudor
Assymetrical contraction of what other muscle actions are used for lateral movements of the jaw?
Contraction of one side of what muscle will shift the mandible to the opposite side?
Suprahyoid and infrahyoid
What 2 divisions are the muscles attached to hyoid bone separated into?
Swallowing and mastication
What actions do the suprahyoid and infrahyoid muscles play an important role in?
Digastric, Mylohyoid, geniohyoid, and stylohyoid
What are the 4 suprahyoid muscles?
Origin and insertion points
What do the names of muscles frequently reflect?
What sheet-like muscle forms the floor of the mouth?
Meets in the middle/the midline
The Mylohyoid muscle meets where before it continues to its insertion point?
Elevation of what bone is important for swallowing?
What are the small, bony projections on the interior surface of the mandibular symphisis?
Depression of the hyoid bone
What is the primary function of the infrahyoid muscles?
Sternothyroid, sternohyoid, omohyoid, and thyrohyoid
What are the infrahyoid muscles?
Skull, a joint capsule, a meniscus (disc) and 3 ligaments
What are the components of the TMJ?
The TMJ is the only one of what kind of joint/articulation on the skull?
Temporal and mandible
What 2 bones make up the articulations of the TMJ?
What covers the articular surfaces of the bones of the TMJ?
Which bone is the cranial articulation of the TJM?
Glenoid (articular) fossa and the articular eminence
What 2 features of the temporal bone make up the articulating area for the TMJ?
External acoustic meatus
The articular fossa is anterior to what?
What is the smooth, rounded ridge that is posterior to the articular fossa and forms the posterior border of the TMJ?
What bone is the facial articulation of the TJM?
The articulating surface of what part of the mandible articulates with the temporal bone in the articular fossa?
The joint capsule
What is fibrous and encloses the TMJ?
TMJ joint capsule
What wraps around the margin of the articular eminence, the articular fossa, and mandibular condyle and neck of the condyle?
What is located between the temporal bone and the condyle in the TMJ?
The shape of the adjacent articulating bones
The shape of the disc conforms to what?
The disc divides the TMJ into how many compartments?
Upper and lower synovial cavities
What are the 2 compartments of the TMJ called?
What fills the synovial cavities and lubes the joints?
Mandibular condyle, Postglenoid process, and the joint capsule
What 3 things are the meniscus/disc attached to?
What is a band of fibrous tissue that connects bones called?
Temporomandibular joint ligament, sphenomandibular ligament, and stylomandibular ligament
What are the 3 paired ligaments associated with the TMJ?
Temporomandibular joint ligament
What ligament is located on the lateral side of each TMJ joint and forms a reinforcement of the joint capsule?
The TMJ ligament prevents what excessive movement of the mandible?
Ramus (attaching just below the neck of the condyle)
The TMJ ligament runs from the zygomatic process of the temporal bone to the posterior surface of what?
What ligament is located on the medial side of the mandible?
The spenomandibular ligament runs from what feature of the sphenoid bone to the lingula of the mandible?
What ligament is located on the medial side of the mandible and distal to the sphenomandibular ligament?
The stylomandibular ligament is located on the medial side of the mandible and distal to the sphenomandibular ligament?
Spenomandibular and stylomandibular ligaments
What 2 ligaments become taut during protrusion of the mandible?
Gliding and rotation
Normal function of the TMJ includes what 2 movements?
What motion of the TMJ is primarily between the disc and the temporal bone?
The disc and condyle glide up and down along what, causing the mandible to protrude and retract?
What motion of the TMJ is primarily in the lower synovial cavity between the condyle and the disc?
Elevation and depression
What movements of the mandible are the results of rotation?
Depression and protrusion
Opening the jaws involves what motions?
Elevation and retrusion
Closing of the jaws involves what motions?
What movements are created by gliding movements on one side of the jaw and little (if any) condular displacement on the other?
Deviation, pain, popping, and limitations
What are the 4 signs of pathology during joint movement?
Temporomandibular disorder (TMD)
What is the name given to pathologies of the TMJ?
What is an example of TMD that involves dislocation of the condyle anterior to the articular eminence causing muscle spasms and an inability to move the condyle back into position?
What is a limitation of mandibular movement often caused by many factors?
What name refers to the sounds the TMJ may make that are associated with displacement of the meniscus?
Popping, clicking, and grinding
What are the sounds the TMJ may make if it has crepitus?