jaw and (extrinsic) tongue muscles Flashcards
jaw muscles important for
mastication (chewing) and speech
two categories of jaw muscles
elevators and depressors
masseter muscle
-deep head, shallow head
-elevates mandible (closes jaw)
-o: zygomatic arch
-i: ramus & angle of mandible
-biting, crushing with teeth
temporal fossa (what and origin for what)
shallow depression on lateral side of skull; origin of temporalis muscle
bone boundaries of temporal fossa
frontal bone, parietal bone, temporal bone, sphenoid bone
temporalis muscle
-fan shape helps elevate and retract mandible (fast closing)
-o: temporal fossa
-i: coronoid process of the mandible
(can feel at temples when clench teeth)
vertical (anterior) fibers of temporalis muscle ___ mandible
elevate
horizontal (posterior) fibers of temporalis muscle ___ mandible
retract
pterygoid muscles
medial and lateral pterygoids; medial elevates mandible; lateral controls side-to-side jaw movement & protrusion of jaw
between the mandible and the pterygoid muscles, which one is closer to the surface?
mandible is closer; pterygoid is deeper inside
medial pterygoids
pairs; elevates mandible
-o: sphenoid bone, palatine bone, maxilla
-i: inner surface of mandible
lateral pterygoids
pairs; controls side-to-side jaw movements and jaw protrusion; good for chewing
-o: sphenoid bone & maxilla
-i: temporomandibular joint disc and condyle of mandible
jaw depressor muscles
anterior belly of digastric muscle, mylohyoid, geniohyoid
which of the following does not contribute to elevation of mandible? temporalis, masseter, medial pterygoid, lateral pterygoid
lateral pterygoid
extrinsic tongue muscles
genioglossus, palatoglossus, hyoglossus, styloglossus
genioglossus (GG)
protracts, depresses, can groove tongue
o: mental spine of mandible
i: throughout tongue, tip to root
anterior (GGa), middle (GGm), posterior (GGp)
t/f: the different sections of the genioglossus can contract independently
true
anterior genioglossus
lowers and retracts tongue front
middle genioglossus
lowers and pulls forward tongue body; creates groove
posterior genioglossus
pulls tongue root forward
palatoglossus
elevates tongue; assists in uvular constrictions, narrows oropharyngeal isthmus (OPI); palatine aponeurosis, sides of tongue body
Hyoglossus (HG)
pulls tongue down and back; greater horn of hyoid bone, inserts into sides of tongue
styloglossus (SG)
traditionally thought to raise and retract tongue; role in speech under review; styloid process of temporal bone, sides of tongue and interlocks with intrinsic tongue muscles
