USMLE Step 1 Neuroanatomy Review 27 02 The Medulla

USMLE Step 1 Neuroanatomy Review 27 02 The Medulla

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Play USMLE Audio MP3 27 02 The Medulla Below

 

Begin 27 02 The Medulla Transcription

Moving on, number 11, the medulla.  We are first going to take a look at the medulla, the rostral medulla.  Please refer to figure 11.1. 

Student doctor, where in the rostral medulla is the medial lemniscus located?

  • The medial lemniscus in the rostral medulla is located near the midline, posterior to the corticospinal tract.

Now, the medial lemniscus in this location carries what kinds of traffic? 

  • Input for proprioception, vibration sensation, and two-point discrimination.

From where? 

  • From the contralateral extremities and the hemitrunk

Where in the rostral medulla is the inferior olivary nucleus located?

  • The inferior olivary nucleus is the most prominent structure in the anterolateral tegmentum.

To where does the inferior olivary nucleus generate output? 

  • The inferior olivary nucleus generates output to the cerebellum.

Now, the inferior olivary nucleus receives input from what two areas?

  • From the cerebral cortex and the brainstem.

How does it function? 

  • It functions as a cerebellar relay nucleus receiving input from the cerebral cortex and the brainstem and generating output to the cerebellum.

Student doctor, where in the rostral medulla is the dorsal motor nucleus of the vagus nerve (cranial nerve ten) located? 

  • The dorsal motor nucleus of the vagus nerve is located lateral to the hypoglossal nucleus along the floor of the fourth ventricle.

What kinds of fibers arise from the dorsal motor nucleus of the vagus nerve?

  • Preganglionic parasympathetic fibers arise from this nucleus.

Student doctor, where in the rostral medulla is the solitary nucleus and tract located?

  • Lateral to the dorsal motor nucleus of the vagus nerve.

Now, the solitary nucleus and tract receive what kinds of fibers from which cranial nerves?

  •  The solitary  nucleus and tract receive afferent taste fibers from cranial nerve seven.

 This services what part of the tongue?

  • The anterior 2/3 of the tongue.

And from cranial nerve nine, which is what part of the tongue?

  • The posterior 1/3 of the tongue.

 And from cranial nerve ten, the vagus, and this is from what structures?

  • The palate and the esophagus.

In the region lateral to the solitary tract and nucleus are a group of cranial nerve nuclei that receive input from the vestibular portion of cranial nerve eight.  Student doctor, what is this cranial nerve nucleus? 

  • This is the vestibular nuclei.

And what is the nucleus located in the anterolateral tegmentum that provides motor innervations to the skeletal muscles innervated by cranial nerves seven, nine, and ten?

  • This is the nucleus ambiguus.

 Now let’s take a look at the inferior cerebellar peduncle.  The inferior cerebellar peduncle transmits fibers to what structure?

  • To the cerebellum.

Now the inferior cerebellar peduncle is transmitting fibers from what two structures to the cerebellum?

  • From the spinal cord and the inferior olivary nuclei.

Student doctor, where in the rostral medulla is the inferior cerebellar peduncle or restiform body located?

  • In the posterolateral medulla.

 

****END OF TRANSCRIPTION****

 

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