Tuesday, April 23, 2013

Lateral medullary syndrome and lateral pontine syndrome mnemonic

*Super super excited to share this mnemonic with you* ^__^
 But let's get to the basics first!

What is lateral medullary syndrome?
Neurological symptoms due to injury to lateral part of the medulla.
Also called Wallenberg's syndrome.

When does it happen?
When the posterior inferior cerebellar artery is occluded.

What is lateral pontine syndrome?
Neurological symptoms due to injury to lateral part of the pons.

When does it happen?
When the anterior inferior cerebellar artery is occluded.

What do both the lesions have in common?

Ipsilateral horner's syndrome.
Why? Descending hypothalamic tracts affected.

Contralateral loss of pain and temperature.
Why? Lateral spinothalamic tract affected.

Ipsilateral cerebellar ataxia.
Why? Cerebellar peduncles affected.
Inferior cerebellar peduncle in medullary and middle cerebellar peduncle in pons.

Nausea, nystagmus, vertigo, vomiting.
Why? Vestibular nuclei involved.

Ipsilateral loss of pain and temperature sensation from the face (facial hemianesthesia).
Why? Spinal trigeminal nucleus and tract involved.

Ipsilateral hearing loss.
Why? Cochlear nuclei and intraxial nerve fibers involved.

So how do I tell the difference between the two? @__@

Lateral medullary syndrome:
Dysphagia, dysarthria, dysphonia
Why? Nucleus ambiguus involved.

Lateral pontine syndrome:
Ipsilateral paralysis of the upper and lower face (lower motor neuron lesion).
Ipsilateral loss of lacrimation and reduced salivation.
Ipsilateral loss of taste from the anterior two-thirds of the tongue.

 Why? Facial nucleus and facial nerve involved.

How do I remember this? Mnemonic! *drum roll*

Lateral medullary syndrome and lateral pontine syndrome mnemonic

Cool fact:
There is a loss of pain and temperature sensation on the contralateral (opposite) side of the body and ipsilateral (same) side of the face. This finding is diagnostic.

That's all!

I created the mnemonic all by myself =D
Hope that was fun and helpful :)



  1. Replies
    1. rocking mnemonic as usual :-)

    2. I have been saying pika pika to all the anonymous comments, shylesh, you make me break the chain!
      Thank you pika pika xD

  2. Just to clarify though, the dysphagia is due to inability to swallow (CN9) right? It has nothing to do with being able to chew (CN5). Beside this little confusion, everything was great, thanks.

    1. Oh well, if you get confused there, you can remember where the nuclei are located =)

      You see, the nucleus ambiguus is present in the medulla and the motor nucleus of the trigeminal nerve is present in the pons. If you get confused between these two, remember the M in Medulla and M in aMbiguus.

      I do agree CN 5 is associated with chewing but it was just a silly mnemonic and since the locations of the nuclei are different, that never crossed my mind! Thank you for letting us know though!
      Maybe we should replace "Pikachu" with the pokemon "Swellow" =P

      PS: Nucleus ambiguus supplies the striated (branchial) muscles of the pharynx, larynx, and upper esophagus via the ninth, tenth, and eleventh nerves. So it's not just CN 9 that is involved.. In fact, for all practical clinical purposes, the ninth nerve cannot be tested separately, and isolated lesions are almost unknown.

  3. Thank you for the great mnemonic.

  4. Great thorough explanation. Thanks!

  5. how s "Drum Roll" Mnemonic works

  6. gud 1...plz give sm mnemonics on LMS and all syndromes

  7. Hey Ikan thanks for helping us out with awesome mnemonic.Any good one for Mca,Aca and Pca?

    1. You're most welcome, Shil.

      Umm, there's one with a diagram. Try Googling it. I'll try posting one myself soon.

  8. How the mnemonic *drum roll* works please? Can someone explain please?? Thanks

    1. Drumroll is an expression used to imagine the sound of drums before introducing something exciting (in the case of the blog, it was the introduction of the mnemonic). The drum roll is not the mnemonic.

      The mnemonic is the Pokemon, Pika-chu. PICA can't chew.


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