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40 Cards in this Set
- Front
- Back
what are the primary muscles of the TMJ
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1) masseter
2) temporalis 3) medial pterygoid 4) lateral pterygoid |
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what muscles are innervated by the mandibular nerve
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1) masseter
2) temporalis 3) medial pterygoid 4) lateral pterygoid |
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the mandibular nerve is a division of what cranial nerve
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trigeminal = cranial nerve V
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where does the mandibular nerve exit the skull
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the foramen ovale
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what components of the TMJ lack sensory innervation
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synovial membrane and central part of articular disc
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where are the pain fibers and mechanoreceptors located
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the periphery of the disc, the capsule, lateral ligament, retrodiscal tissue
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what does bilateral contraction of the masseter do
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- elevates the mandible to bring the teeth into contact for effective grinding and crushing of food
- protrudes the mandible slightly |
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what does unilateral contraction of the masseter do
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causes slighty ipsilateral excursion of the mandible
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what are the two sets of fibers of the masseter
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superficial and deep
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where does the temporalis muscle lie
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fills most of the concavity of the temporal fossa of the skull
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what does bilateral contraction of the temporalis cause
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elevation of the mandible (the oblique fibers elevate and retrude)
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what does unilateral contraction of the temporalis cause
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slighty ipsilateral excursion of the mandible
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what two muscles of mastication have very similar line-of force and size
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medial pterygoid and masseter
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what does bilateral contraction of the medial pterygoid cause
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elevates and protrudes the mandible
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what does unilateral contraction of the medial pterygoid cause
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effective contralateral excursion of the mandible
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what are the divisions of the lateral pterygoid
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superior and inferior head
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explain the direction of the lateral pterygoid
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traverses nearly horizontally to insert into the neck of the mandible at the pterygoid fossa, articular disc, and the capsule of the TMJ
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where do the fibers of the superior head of the lateral pterygoid attach
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into the medial wall of the capsule and relatively small portion to the medial side of the articular disc
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activation of the superior head of the lateral pterygoid casues
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an anterior-medial force on the capsule and disc
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what does unliateral contraction of both heads of the lateral pterygoid cause
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- contralateral excursion of the mandible
- rotates the ipsilateral condyle anterior-medially within the horizontal plane |
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what does bilateral contraction of both heads of the lateral pterygoid produce
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strong protrusion of the mandible
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how do the two heads of the lateral pterygoid effect closing and opening of the mouth
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they have antagonistic roles inferior head is primary depressor of the mandible (especially during resisted opening of the mouth) and the superior head helps control the position of the disc and joint during elevation
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what are the secondary muscles of mastication
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suprahyoid and infrahypoid muscles
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what are the suprahyoid muscles
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digastrics, geniohyoid, mylohyoid and stylohyoid
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where do the suprahyoid muscles attach
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between th ebase of the cranium, the hyoid, and the mandible
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where do the infrahyoid muscles attach
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superiorly to the hyoid and inferiorly to the thyroid cartilage, sternum, and scapula
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how do the infrahyoid and suprahyoid muscles work together
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infrahyoid muscles stabilize hyoid bone while the suprahyoid muscles assist with depression of mandible
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what other actions are the suprahyoid and infrahyoid muscles involved in
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speech, tongue movement, swallowing, and controlling boluses of food prior to swallowing
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opening of the mouth is performed primarily through contraction of which muscles
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inferior head of lateral pterygoid and suprahyoid muscles
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what muscels are primarily responsible for protrusion of the mandibular condyle
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inferior head of the lateral pterygoid
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what muscles have a rotation "force-couple" for the mandible
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inferior head of the lateral pterygoid with the suprahyoid
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when does the disc-and-condyle slide forward
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during late phase of opening the mouth
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what pulls the disc anteriorly
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1) colalteral ligaments attaching the disc to the translating condyle
2) the increased intra-articular pressure created by activation of the inferior head of the lateral pterygoid |
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despite its attachment directly to the disc, which muscle is inactive while opening the mouth
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the superior head of the lateral pterygoid
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closing the mouth against resistance is performed primarily by which muscles
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masseter
medial pterygoid temporalis |
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what muscle retrudes the mandible during closing of the mouth
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the oblique posterior fibers of temporalis
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what direction is the mandible translated during retrusion
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posterior-superior, helping to reseat the condyle in the fossa
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describe the action of the superior head of the lateral pterygoid while the mouth is closing
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acts eccentrically to create forward tension on the disc and neck of the mandible.... stabilizing and positioning the disc between the condyle and articular eminence
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in addition to pain in the muscles and joint during movement, what are some additional symptoms included in TMD
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joint sounds, reduced molar bite forces, limited ROM in mouth opening, tension headaches, joint locking, referred pain to face and scalp, nocturnal eruxism
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what is nocturnal eruxism
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teeth grinding while sleeping
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