USMLE Step 1 Review 02 17 Anatomy Muscles of Mastification

USMLE Step 1 Review 02 17 Anatomy Muscles of Mastification

 

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Play USMLE Audio MP3 02 17 Anatomy Muscles of Mastification Below

 

Begin 02 17 Anatomy Muscles of Mastification Transcription

Alright for CN V, we’ve gone over taste, texture, and salivation.

What is our fourth function in digestion?

  • Mastication.

What are the four muscles of mastication innervated by CN V? 

  • Masseter, medial, and lateral ptyergoids, and temporalis.

Which division of CN V, the trigeminal, supplies all four muscles of mastication?

  • The mandibular division.

What is the nerve to the medial pytergoid?

  • It’s called the nerve to medial pyterygoid.

And the nerve to temporalis?

  • Deep temporal nerve.

And the nerve to lateral pytergoid?

  • Lateral pyergoid nerve.

And the nerve to masseter?

  • Masseteric nerve.

Which of these muscles of mastication open the mouth?

  • The lateral pytergoids.

What’s a memory key for remembering that the lateral ptyergoids are the ones that open the mouth?

  • Lateral loosens.

And what’s the memory key for remembering which 3 of the muscles of mastication cause the mouth to close?

  • Mash mouth together.  MMT.

And what are the 3 muscles of mastication that close the mouth?

  • Masseter, medial pytergoid, temporalis.

Alright, in the same order then, what would be the three nerves innervated branches of the mandibular division of the trigeminal which cause the mouth to close?

  • Masseteric nerve, nerve to medial pyterogoid, and the deep temporal nerve.

Which of the muscles of mastication act to move the jaw laterally? 

  • The lateral pytergoid muscles.

Which of the two lateral pyergoids would move the jaw to one side?

  • The lateral pyergoid on the same side.

Which pair of muscles working together protrude the jaw, jut the mandible forward?

  • Again, the lateral ptyergoid muscles except this time, working together.

And finally, which pair of muscles working together causes the jaw to retract?

  • Temporalis muscles.

So what branch of the mandibular branch of the trigeminal is involved in innervating retraction of the jaw?

  • The deep temporal nerve.

And what’s the memory key just for review for knowing which muscle moves the jaw laterally?

  • Lateral is lateral.

The masseter muscle is actually in two parts. What are the two parts?

  • The deep part and the superficial part.

Of these 3 muscles, the deep part and the superficial part of the master, and temporalis, which is the most deep?

  • Temporalis.

To what part of the mandible does temporalis attach?

  • The coranoid process of the mandible.

Why is temporalis the one involved in retracting the mandible?

  • Because the angle of the fibers of the coranoid process of the mandible back to the temporal bone is diagonal – mostly superior but somewhat posterior.

****END OF TRANSCRIPTION****

 

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