Medulla Anatomy

Question 1

What are the two longitudinal prominences of the medulla observable anteriorly?
(1) & (2) as indicated in the image attached.

Answer 1

The medial longitudinal prominences are the pyramidal pathways (1).
The more lateral longitudinal prominences are the olive pathways (2) (contain olivary nuceli).

Question 2

What is the prominence of the medulla observable in lateral view?

Answer 2

The inferior cerebellar peduncle is observable in lateral view of the medulla.

Question 3

What part of the medulla forms the floor of the 4th ventricle.

Answer 3

The upper portion of the posterior part of the medulla forms the floor of the 4th ventricle.

Question 4

There are two significant ‘triangles’ located within the medullary region of the floor of the 4th ventricle. Can you identify these?

Answer 4

1. The hypoglossal triangle is located medially and the vagal triangle more laterally.

Question 4

There are two continuations of the spinal cord into the lower medulla posteriorly. These two continuations end in tubercles. Can you name the two continuations?

Answer 4

Posteriorly within the lower medulla the Gracile fascicle (2) (posterio-medial) and the Cuneate fascicle (4) (posterio-lateral) terminates in the Gracile (1); Cuneate tubercles (3). These structures contain the DCML pathways.

Question 5

Which cranial nerves are located within the medulla?

Answer 5

CN VIII Vestibulocochlear
CN XI Glossopharengeal
CN X Vagus
CN XI Accessory
CN XII Hypoglossal

Question 6

What three nuclei are visible as elevations in the floor of the 4th ventricle in the upper region of the medulla?

Answer 6

1. Hypoglossal triangle contains the hypoglossal nuclei.
2. Vagal triangle contains the vagal nuclei.
3. The inferior portion of the vestibulocochlear nuclei is located most laterally.

Question 7

What two nuclei are located posteriorly in the lower medulla?

Answer 7

The Gracile (medially) and the Cuneate nuclei are located posteriorly in the lower medulla.

Question 8

What is located as indicated by the blank label in this medulla cross section?
What runs in these tracts?

Answer 8

Lateral spinothalamic spinal tract.

Pain & temperature.

Question 9

What is Wallenberg syndrome / Lateral medullary syndrome?

Answer 9

Lesions that effect the lateral medulla which give rise to characteristic clinical presentations.

Question 10

Name the structures identified, that are effected in Wallenberg syndrome / Lateral Medullary syndrome.

Answer 10

Question 11

Disruptions to blood supply via which cerebral artery is often associated with Wallenberg syndrome / lateral medullary syndrome?

Answer 11

Posterior inferior cerebral artery supplies the medulla therefore disruptions to this flow is often associated with Wallenberg syndrome.

Question 12

In Wallenberg / lateral medullary syndrome the following nuclei are effected, causing characteristic clinical features. Please list a clinical feature for each nuclei involved.

Answer 12

1. Lateral spinothalamic tract - loss of pain sensation / temperature on contralateral side.
2. Inferior cerebella peduncle - loss of coordination on ipsilateral (same side of body).
3. Vestibulocochlear nuclei - vertigo.
4. Ambiguus nucleus - difficulty swallowing and hoarseness of voice.
5. Vagus nucleus.