Medulla Anatomy

Question 1

Why is meant by the closed medulla?

Answer 1

The medulla below the opening of the 4th ventricle.

Question 2

What structure becomes the 4th ventricle?

Answer 2

The spinal canal.

Question 3

Which direction does the spinal canal migrate to become the 4th ventricle?

Answer 3

Dorsally.

Question 4

Which portion of the medulla is referred to as the “true” medulla?

Answer 4

The open medulla

Question 5

What does the (non-horn) gray matter of the spinal cord become in the medulla?

Answer 5

The reticular formation

Question 6

Is the motor decussation found in the upper or lower closed medulla?

Answer 6

Lower

Question 7

Is the sensory decussation found in the upper or lower closed medulla?

Answer 7

Upper

Question 8

What cranial nerve motor nucleus is found in the lower closed medulla?

Answer 8

Cranial nerve XI.

Question 9

What fibers make up the pyramids found in the medulla?

Answer 9

Corticospinal fibers

Question 10

What portion of the corticospinal fibers cross in the medulla?

Answer 10

85 %

Question 11

Where are the 15% of corticospinal fibers that do not cross found?

Answer 11

In anterior funiculus

Question 12

Where do the cranial nerve XI fibers exit the medulla?

Answer 12

Through the ventral horn

Question 13

Do the CN XI fibers ascend or descend after leaving the medulla?

Answer 13

Ascend

Question 14

What spinal region contributes fibers to CN XI?

Answer 14

The upper C-region

Question 15

What sulcus disappears in the lower closed medulla?

Answer 15

The ventral median sulcus

Question 16

What muscles are supplied by CN XI?

Answer 16

SCM

Upper trapezius

Question 17

What cranial nerve sensory nucleus is found in the lower closed medulla?

Answer 17

Spinal nucleus of CN V.

Question 18

What sensory information is sent to the spinal nucleus of CN V?

Answer 18

Pain and temperature of the face.

Question 19

What nuclei are found in the upper closed medulla?

Answer 19

• Nucleus gracilis

- Nucleus cuneatus

Question 20

What do the crossing fibers of the NG and NC form?

Answer 20

The medial lemniscus

Question 21

What are the crossing fibers of the NG and NC called individually?

Answer 21

Internal arcuate fibers

Question 22

Do the fibers of the lower extremity (sensory or motor) cross rostrally or caudally in the medulla?

Answer 22

LE cross more caudually

Question 23

Do the fibers of the upper extremity (sensory or motor) cross rostrally or caudally in the medulla?

Answer 23

UE cross more rostrally.

Question 24

What is the somato-topical arrangement of the medial lemniscus?

Answer 24

From anterior –> posterior

Sacral –> Cervical

Question 25

What 4 nuclei are begin at/ are unique to the open medulla?

Answer 25

- CN XII nuclei - CN X motor nucleus - Solitary Nucleus/ Nucleus of Tractus Solitarii - Nucleus Ambiguus

Question 26

What nucleus continues from the closed medulla into the open medulla?

Answer 26

- Spinal Nucleus of CN V

Question 27

What tract begins at the level of open medulla?

Answer 27

- Inferior cerebella peduncle

Question 28

What is the path of CN XII's fibers from its nucleus in the open medulla to the tongue?

Answer 28

- Travels ventrally and exits medulal between pyramids and olive - Ascends upwards - Enters tongue

Question 29

To which side will a tongue deviate when protracted in a unilateral CN XII lesion?

Answer 29

To the lesioned side

Question 30

How do the fibers of the dorsal motor nucleus of the vagus nerve exit the open medulla?

Answer 30

Laterally, with a ventral orientation

Question 31

What autonomic nervous system makes up the dorsal motor nucleus of CN X?

Answer 31

Parasympathetic NS

Question 32

What structures are innervated by the motor elements of CN X?

Answer 32

- Neck and below, except for lower GI

Question 33

What 3 cranial nerves make up the cell column of the nucleus ambiguus?

Answer 33

9 10 11

Question 34

How are the cranial nerves oriented in the nucleus ambiguus from superior to inferior? (dorsal to ventral???)

Answer 34

9 10 11

Question 35

What structures are innervated by the efferent fibers of the nucleus ambiguus?

Answer 35

- Pharynx | - Larynx

Question 36

What symptoms result from a lesion to the nucleus ambiguus?

Answer 36

- Dysarthria | - Dysphagia

Question 37

What 3 cranial nerves make up the cell column of the solitary nucleus?

Answer 37

7 9 10

Question 38

What information is processed by the lower half of the solitary nucleus?

Answer 38

- General visceral afferent information from the neck and body wall

Question 39

What information is processed by the upper half of the solitary nucleus?

Answer 39

VII: Anterior 2/3rds of tongue (SVA/ Taste) IX: Posterior 1/3rds of tongue (SVA/ Taste) X: Afferent information of oropharynx

Question 40

What 3 nuclei at the level of the open medulla are involved with fibers of CN X?

Answer 40

- Solitary nucleus - Nucleus Ambiguus - Dorsal motor nucleus of CN X

Question 41

What 3 nuclei are found in the transitional area between the medulla and pons?

Answer 41

- Vestibular nuclei - Cochlear nuclei - Accessory Cuneate Nucleus

Question 42

What CN projects to the cochlear and vestibular nuclei? From what orientation does it enter the brain stem?

Answer 42

- CN VIII | - Enters laterally

Question 43

What is the function of the vestibular nuclei?

Answer 43

Communicate with the vestibular apparatus in the inner ear

Question 44

What component of CN VIII projects to the vestibular and cochlear nuclei?

Answer 44

Special somatic afferent

Question 45

What tract originates at the accessory cuneate nucleus?

Answer 45

Cuneocerebellar tract

Question 46

What structure communicates the medulla to the cerebellum in the transitional area between the pons and medulla?

Answer 46

The inferior cerebellar peduncle

Question 47

What effect will a lesion to the ICP at the transitional area have on an individual?

Answer 47

Pt will lose proprioception of the body and face