red nucleus

[StressedMedStud]

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Can someone explain to me what red nucleus is? I have read it in books but I can seem to understand it or remember what I read. Can someone simplify it for me?

Also what other tracts besides the 3 main ones are important for step 1? Spinocerebellar? Rubrospinal?

 

[thehundredthone]

The red nucleus is present in the midbrain at the level of the superior colliculus.

It is part of a cerebellar connection called the globose-emboliform-rubral outflow. I know you said simplified, so bear with me here. The globose-emboliform nuclei are in the intermediate zone of the cerebellum, which generally deals with control of non postural musculature. So, from the cerebellum to the (contralateral) red nucleus, and then onward as the rubrospinal tract (which crosses), to control non postural musculature - mainly the flexors of the upper limb ipsilaterally.

Here you can tie in the clinical relevance. Lesions above the red nucleus lead to decorticate posturing - upper limbs flexed + lower limbs extended, and lesions below it lead to decerebrate posturing - upper limbs (+ lower limbs) extended.

So basically, the rubrospinal tract is a pathway for the cerebellum to help control the movements of the ipsilateral upper limb (along with the dentato thalamic outflow).

 

[StressedMedStud]

the red nucleus is present in the midbrain at the level of the superior colliculus.

It is part of a cerebellar connection called the globose-emboliform-rubral outflow. I know you said simplified, so bear with me here. The globose-emboliform nuclei are in the intermediate zone of the cerebellum, which generally deals with control of non postural musculature. So, from the cerebellum to the (contralateral) red nucleus, and then onward as the rubrospinal tract (which crosses), to control non postural musculature - mainly the flexors of the upper limb ipsilaterally.

Here you can tie in the clinical relevance. Lesions above the red nucleus lead to decorticate posturing - upper limbs flexed + lower limbs extended, and lesions below it lead to decerebrate posturing - upper limbs (+ lower limbs) extended.

So basically, the rubrospinal tract is a pathway for the cerebellum to help control the movements of the ipsilateral upper limb (along with the dentato thalamic outflow).

thanks so much!!!!

 

[Phloston]

Since the rubrospinal tract, via the red nucleus, is responsible for upper limb flexion and lower limb extension (as far as I'm aware), lesions above are like UMN and those below are LMN. So lesions above are hyper-upper limb flexion whereas those below are loss of upper limb flexion.

You can remember that decorticate is the "mummy" posture because the arms are at the core of the body, whereas decerebrate posture is extension of the limbs by one's side.

Decerebrate (2 on Glasgow coma scale) is worse than decorticate (3 on Glasgow coma scale).

 

[StressedMedStud]

Since the rubrospinal tract, via the red nucleus, is responsible for upper limb flexion and lower limb extension (as far as I'm aware), lesions above are like UMN and those below are LMN. So lesions above are hyper-upper limb flexion whereas those below are loss of upper limb flexion.

You can remember that decorticate is the "mummy" posture because the arms are at the core of the body, whereas decerebrate posture is extension of the limbs by one's side.

Decerebrate (2 on Glasgow coma scale) is worse than decorticate (3 on Glasgow coma scale).

THANK YOU THANK YOU!!! Thats a great mneumonic!

 

[Phloston]

I actually kept mixing up decorticate and decerebrate for a while. I was studying with a first-year student a few weeks ago who said he remembers it that way. Definitely helps.