NBME 24 Lateral pterygoid (NBME Answers)

Retired NBME 24 Answers

nbme24/Block 2/Question#10 (reveal difficulty score)
A 29-year-old man is brought to the emergency ...
Lateral pterygoid 🔍 / 📺 / 🌳 / 📖
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submitted by ∗neonem(630)

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Pg 491 in FA 2018 (Neurology anatomy & physiology section): 3 muscles close the jaw: Masseter, teMporalis, Medial pterygoid 1 muscle opens the jaw: Lateral pterygoid ALL are innervated by trigeminal nerve, V3 Mnemonic: M's munch (close the jaw), L's lower (loosen/relax the jaw)

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sunshinesweetheart p 495 in FA 2019 +3

mnunez187 p 507 in FA 2020 +

fmlusmle UW 18598 +

+3 upvote downvote
submitted by ∗drpee(68)

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According to FA 2019 pg. 495 contraction of lateral pterygoids help lower the jaw, making the answer to this question seem counter intuitive. (Wouldn't you need the jaw to be open to slide the mandible back into the TMJ?) Consider, however, that the lateral LPs also facilitate protrusion of the jaw. Thus, their relaxation would make it easier to reduce the joint.

I found this video helpful for getting a visual of the LPs.

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maria_danieli i thought that when a TMJ dislocation isn't reduced quickly your muscles kind of contract in that position.. since in ATM dislocation your mouth is open you have a contracture of lateral pretygoids that prevents mouth's closure TMJ. to slide the mandible back you need to relax them otherwise the mouth won't close! Same as shoulder dislocation, you must act tempestively otherwise you'll need BZD to relax muscles could this be an explanation? +3

jj375 Agreed, it says that the person is drooling and has an "inability to elevate the jaw" therefore it is stuck in the lowered position --> a spasm of the Lateral pterygoid. I always remember it since its the only MUSCLE OF MASTICATION starting with an L there its the only one that LOWERs the mandible. Medial pterygoid, masseter, temporalis all help raise the mandible/jaw. Masseter also helps retracts the jaw. +

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submitted by ∗neil_simmons(5)

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If you're an idiot like me, this question is easiest to answer if you knew that the lateral pterygoid is the only muscle of the options listed involved in movement of the jaw.

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submitted by ∗an_improved_me(91)

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clench my external sphincter any time i see answers with muscle names like mylohyoid, digastric, levator veli palatini...

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-6 upvote downvote
submitted by ∗isaacyo94(13)

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The answer is always lateral pterygoid. Except when its not. Trust me.

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unknown001 wait... what ??? +

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