2011-04-25

Chew On This.

Hope everyone's Easter went well. I celebrated exactly as intended: went for a walk in the sun (that did come out of hiding!), heard some birds, saw many yellow tulips, and devoured this chocolate.

Today was my Anatomy final exam. Bum, bum, bum! I spent all weekend studying for this exam; over one hundred pages of lecture material to be read, memorized, and most importantly, understood. If there is one thing I've learned about writing Dr. T's Anatomy exams, it's that you need to understand the concepts rather than just regurgitate what was taught. Speaking of understanding, one of the questions was about melatonin (see? my blog helps me study!).
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Muscles of Mastication (i.e. Chewing Muscles): We have four main muscles that help us to chew: the Temporalis, Masseter, Medial Pterygoid, and the Lateral Pterygoid muscles. These muscles work together to allow us to preform the following jaw/mouth movements:

Depression - i.e. open the mouth, this is the most interesting movement because it is done mostly by gravity. Normally our mouth is elevated (see below), but when we sleep, our elevator muscles are relaxed and then gravity kicks-in, causing our mouth to sag open. Hence why some people drool while sleep, because their mouth is open!
Elevation - i.e. close the mouth, muscles: temporalis, masseter, medial pterygoid
Protrusion - i.e. pushing your chin out as far as possible, muscles: lateral pterygoid (mostly), temporalis, masseter
Retraction - i.e. pulling your chin deeper into your head, muscles: temporalis, masseter
Grinding/Back-and-Forth - this action is preformed by contralateral (opposite side) protruders, and ipsilateral (same side) retractors

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