Neuroanatomy, decussations, commissures, spinal tracts, upper & lower motor neurones

Strap yourselves in, this one's a bit of a monster. It's not always best to chop up anatomy into small chunks because it helps to link bits together, to make sense of it all. I'm going to talk about decussations within the nervous system, that is, nerve fibres crossing over from one side of the body to the other.

We'll talk about:
- decussations and commissures
- spinothalamic tracts, dorsal columns (sensory)
- corticospinal tracts (motor)
- upper motor neurones vs lower motor neurones
- the weird things that can happen when only half of the spinal cord is injured

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[studyorrelaxationmusic]

You have turned anatomy into something very interesting for a person who used to procrastinate hearing the word Anatomy... thank u very much sir. I am watching your videos back to back without even getting slightly bored.

[oganesson]

I can't thank you enough for actually making this video. You have turned something so complex into something so simple/straight forward and with freaking pipe cleaners!!! You sir are a genius and an outstanding teacher.
Hopefully we can see more neuoranatomy videos, especially one on cranial nerve decussations in the future.
Cheers!

[jessicamarchiori]

I can't thank you enough, for 3 years I've been trying to learn this. My final exam is on Wednesday and I have finally been able to get in a way I can explain it. you are an absolute lifesaver. you are a natural teacher. Great visuals. xoxoxoxox

[margaritaasparuhova]

Fist time I watch the videos - I got fascinated and excited about the topic and by the way you teach. Second time I put my efforts into learning - writing, drawing, talking about it with my loved ones - and I am really learning - all thanks to your great teaching. Thank you so SO much....

[angelainglismusic]

Boy oh boy, are you fabulous. Thank you so much. You're a pleasure to watch and listen to. So much better than text books.

[ianliwag]

Amazing instructor and very honest educator. Thank you so much, Sam.

[agie]

You make it way easier for me to understand Doc. Thank you. I like how honest you are too when you said that it's a bit challenging to learn NeuroAnatomy even though you are the best at teaching.

[drdoody]

Dear Sam,
you've been extremely thorough and presenting stuff that can be iffy and too solid for any fun in a very unique & exciting way. This is in almost all (if not all) your teaching video posts - I haven't seen them in total.

Please allow me to mention the following that might be additive for more clarity, if not mistaken:

- The spinothalamic tract (ascending) is subdivided into:
1) Lateral spinothalamic tract - the main one and for pain & temperature. It decussate "Two Segments" above entry.
2) Anterior spinothalamic tract - for crude touch & pressure. It decussate similar to above.
- The dorsal & ventral spinocerebellar tract (ascending) - the ventral doesn't decussate, while the dorsal decussate twice. Thus lesions are always "ipsilateral". It's for unconscious proprioception. This one is a bit confusing but clinically important.

- The corticospinal tract (descending) is also subdivided into:
1) Lateral corticospinal tract (pyramidal tract at medulla) - decussate at inferior part of medulla, and for muscles of the limbs.
2) Anterior corticospinal tract - decussate at segmental levels, and for muscles of the trunk.
- The rubrospinal (from red nucleus) tracts (descending) - decussate early in its pathway, and for flexors & extensors muscles.
- The reticulospinal (from reticular system) tracts (descending) - doesn't decussate, and only for supplementing and facilitating the corticospinal tract(s). This is a key point in some aspects of rehabilitation recovery in very simple terms.

Human body is amazingly formed and created! We will keep forever discovering & confirming this fact.
Happy for your feedback!

[caitlinmoore]

I wish I'd found this channel before, I've never picked anatomy up so fast! Great teacher

[futurephysio]

If there was ever a video I needed two weeks

[phubusa]

Your lectures are so interesting!!! The way you make use of the visual aids have improved my understanding of the discussions!!!

[NixQuit]

Spent honestly 4hrs+ trying to understand this topic using a variety of sources. This video was finally the one that made it 'click' for me - thank you!

[golffitnessireland]

I just love sit sit down on Saturday evening after work put feet up and watch your videos! Such interesting and great entertainment!

[harikachawhan]

love from India Sam..u are a life saver.. thanks buddy

[wandaterry]

I really find it interesting the discussions that this has brought about which is more learning. Love it!!!

[mohammadadnan]

YOU'RE A DAMN GENIUS!! For this 'experiment'

[sonia_uc]

thank you so much prof, i have been struggling with neuroanatomy and hearing you say it’s hard even for you makes me feel a lot better❤️

[jentomholbarrett]

Thank you, it looked really painful talking about it, but you made it really easy to understand. thank you so much.

[suefowler]

Thanks for tackling that. From my point of view it was definitely worth doing. Thanks again.

[bernard_wandera]

watching this from Kenya, I love your work.