Erector spinae (back muscles)
Summary
TLDRThis educational video script delves into the complex anatomy of the back muscles, breaking them down into layers: superficial, intermediate, and deep. It explains the functions of these muscles, particularly the erector spinae, which is crucial for back extension and rotation. The script also touches on the deeper transverse spinal muscles, hinting at their role in back pain and spasms.
Takeaways
- 📚 The script discusses the anatomy of the back muscles, focusing on their complexity and layers.
- 💪 The muscles of the back are categorized into superficial, intermediate, and deep layers, each with specific functions.
- 🤔 The main challenge for students is to understand the various muscles and their functions, as well as how to locate them.
- 🏋️♂️ The superficial muscles, such as the trapezius and latissimus dorsi, are primarily involved in moving the upper limb.
- 🌟 The intermediate layer includes muscles like serratus posterior inferior, which assists in respiration by bracing and pulling down the ribs.
- 🔍 The deep muscles, also known as intrinsic muscles, are crucial for back extension and include the erector spinae group.
- 🧍♂️ The erector spinae muscles are responsible for extending the vertebral column when standing up from a bent position.
- 🔑 The deep muscles are further divided into spinalis, longissimus, and iliocostalis, based on their attachment points on the spine.
- 📐 These muscles are also categorized by the region of the spine they affect: lumbar, thoracic, cervical, and capitis for those attaching to the head.
- 🌀 The splenius muscles, part of the deep layer, attach to the head and are involved in neck rotation and extension.
- 🔬 There is an even deeper layer of muscles called the transversospinales, which are involved in back pain and spasms and will be discussed in a subsequent session.
Q & A
What is the main focus of the video script?
-The main focus of the video script is to explain the muscles of the back, breaking them down into layers and discussing their functions.
What are the superficial muscles of the back?
-The superficial muscles of the back include the trapezius, latissimus dorsi, and rhomboids. These muscles are primarily involved in moving the upper limb.
What is the role of the serratus posterior inferior muscle?
-The serratus posterior inferior muscle helps in respiration by bracing and pulling the ribs down.
What are the intermediate layer muscles of the back?
-The intermediate layer muscles include the serratus posterior inferior and serratus posterior superior. These muscles are involved in elevating and bracing the ribs.
What is the primary function of the deep muscles of the back?
-The primary function of the deep muscles of the back, also known as the intrinsic muscles, is to extend the vertebral column, helping to stand up straight from a bent position.
What is the term used to collectively refer to the deep group of intrinsic muscles of the back?
-The deep group of intrinsic muscles of the back are collectively referred to as the erector spinae.
How are the muscles of the back categorized based on their location?
-The muscles of the back are categorized based on their location as spinalis, longissimus, and iliocostalis, which run from medial to lateral.
What are the three groups of muscles that make up the erector spinae?
-The three groups of muscles that make up the erector spinae are spinalis, longissimus, and iliocostalis.
What is the function of the splenius muscles in the neck?
-The splenius muscles in the neck, specifically the splenius capitis and splenius cervicis, help in extending the neck and rotating the head.
What is the significance of the erector spinae in everyday movements?
-The erector spinae play a crucial role in everyday movements such as flexion and extension of the back, lateral flexion, and rotation.
What is the deeper layer of muscles in the back that is mentioned in the script?
-The deeper layer of muscles in the back mentioned in the script is the transversospinalis muscles, which are involved in back pain and spasms.
Outlines
📚 Introduction and Overview of the Back Muscles
The introduction of the video acknowledges the complexity of the back muscles. The speaker mentions the challenge students face in understanding the different layers and functions of the back muscles. They propose breaking the information down into manageable chunks to make it easier to comprehend. The introduction also highlights the importance of understanding these muscles for proper anatomical knowledge.
🔍 Superficial and Intermediate Muscles of the Back
The speaker discusses the superficial muscles of the back, including trapezius and latissimus dorsi, which are mainly involved in moving the upper limb. They also introduce the intermediate muscles like serratus posterior inferior and superior, which assist in respiration by bracing and moving the ribs. These muscles are described as extrinsic muscles of the back, which will be set aside for the focus on deeper layers.
🏋️ Deep Muscles and Their Functions
The focus shifts to the deep, or intrinsic, muscles of the back, which are primarily responsible for extending and stabilizing the vertebral column. The erector spinae group is introduced, consisting of spinalis, longissimus, and iliocostalis muscles. These muscles work to extend the back and provide lateral flexion and rotation. The importance of understanding these muscle groups and their anatomical positions is emphasized.
🔎 Specific Deep Muscle Groups and Their Roles
The detailed anatomy of the erector spinae group is explored, with emphasis on their divisions based on regions of the spine: lumborum, thoracis, cervicis, and capitis. The speaker explains how these muscles interact and their specific roles in movements and stability of the spine. The video highlights the complexity of these muscle groups and their importance in maintaining posture and facilitating various movements.
Mindmap
Keywords
💡Muscles of the back
💡Trapezius
💡Latissimus dorsi
💡Serratus posterior inferior
💡Erector spinae
💡Spinalis
💡Longissimus
💡Iliocostalis
💡Splenius
💡Intrinsic and extrinsic muscles
💡Lumbar, thoracic, cervical, and capitis regions
Highlights
Introduction to the complexity of the back muscles and the approach to understanding their structure and function.
Explanation of the superficial muscles of the back, including the trapezius and latissimus dorsi, and their role in moving the upper limb.
Identification of the nuchal ligament covering the spinous processes and its relevance to the muscles discussed last week.
Introduction to the intermediate layer of back muscles, including serratus posterior inferior and its function in respiration.
Description of the deep muscles of the back, also known as intrinsic muscles, and their primary function in extension of the vertebral column.
The role of deep muscles in lateral flexion and rotation of the back, with a focus on the quadratus lumborum.
Overview of the erector spinae muscle group, which includes various muscles responsible for the extension of the back.
Differentiation of the three medial to lateral groups within the erector spinae: spinalis, longissimus, and iliocostalis.
Regional classification of the erector spinae muscles based on their attachment to different regions of the vertebral column.
Introduction to the splenius muscles, which are part of the deep layer and attach to the head, contributing to neck rotation and extension.
The importance of understanding the functional units of the back muscles in relation to the vertebral column and their movements.
Discussion on the complexity of the back muscles and the strategy to break down this complexity into manageable parts.
Mention of the even deeper layer of muscles, the transversospinal muscles, and their involvement in back pain and spasms.
Emphasis on the importance of not giving up when faced with the intricate anatomy of the back muscles.
Encouragement to stay engaged with the material, promising that understanding the back muscles will become clearer over time.
Summary of the key points covered in the session, including the anatomy and function of the back muscles and their layers.
Transcripts
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hello okay this is a challenging one
then last week we looked at vertical
bones and I said that we would next look
at the muscles of the back so I've got
lots of different models that show lots
of different bits of the back the trick
is that there are an awful lot of bits
of the back and lots of layers so
there's a student your difficulty is oh
my how do I untangle all of this how do
I work out what's what how do I manage
all of these structures and understand
what they do where they are is stuff
like that I mean I imagine the last you
just kind of look at the back and give
up so what we'll do is we'll break it
down into chunks into layers and it will
make sense right but the other trick
I've got is do I have enough things to
show the things that I want to talk
about don't know the thing applies they
forgot your skeleton here I can fit him
in and as I go in here I go wee man over
here
so we'll rotate around until we can do
right okay the muscles on the back then
see let's see this model here on this
side we see the superficial muscles of
the back so you can see trapezius up
here and we can see latissimus dorsi all
of these muscles of the back are very
very superficial you can see the spinous
processes covered by the nuchal ligament
here
we will talk about the spinous processes
of the vertebra last week and you can
palpate me on your own back on you and
these superficial muscles are actually
moving the upper limb really so we
talked about those when we're talking
about the shoulder on the upper limb so
that this is the most this is the
superficial layer of muscles of the back
today
we can ignore them these also known as a
layer of extrinsic muscles of the back
so trapezius that isthmus d'Orsay the
rhomboids all these guys think they're
gone in that first layer of the
superficial muscles of the back in the
next layer are the intermediate group
and there are only a couple of muscles
here right so do you see this this is
serratus posterior inferior hopefully
you remember serratus anterior as the
boxers muscle the sweetest anterior
muscle is passing from the ribs gives
you all those fingers so slips of muscle
you see and on the sides of super-heroes
massive chests and these pull length of
the scapula and they pull the scapular
anteriorly right which gives you that
reach give the box for some of the power
of their punch so that's the rate as
anterior that's not a muscle of the back
that's a muscle of the shoulder of the
upper limb but this is why this is
called serratus anterior because this is
serratus posterior and this is serratus
posterior inferior so laters could is
serrated serrated because it's a passion
to the ribs and it's going down to the
vertebra here we're doing all these
muscles today as well we talked about
these muscles when we talked about
respiration so
so eaters posterior inferior braces the
ribs and I'll pull the ribs down helping
with exploration right and if there's a
serratus posterior inferior and there
must be a straightest posterior superior
and there it is up here we can't see it
but these are the intermediate layers
which we just posterior superior there
are tears form underneath the rhomboid
and they're elevating the ribs and also
bracing the ribs that's going to need a
group of muscles of the back also
extremely muscles of the back also
something we're going to ignore today
and then we get down to the intrinsic
muscles of the back also known as the
deep muscles of the back this is the
deep group of the deep layer and they're
these muscles that you can see here now
we need to think about what the function
of these muscles is if these other
muscles we've been talking about moving
the upper limb and bracing the ribs and
that sort of thing
what do the deep group of muscles of the
back do women need our backs to do it's
one of the reasons there's always a
skeleton in my Amin frame is that he's
usually what I focus on so that when I
stand by it
I should be in focus he's more focused
on me she is focused on me okay so what
we do with our backs then well one of
the big things we do is that when we're
bent over we stand up straight again and
what we're doing here is all this is
them so this would be flexion of the
back of this way and then just stand up
again this would be extension of the
vertebral column or extension of the
back right so these deep muscles of the
back I mean one thing they're working
eccentrically to lower us like this and
then they're contracting working
concentric ly to extend the back and you
can extend further as well right
currently something else we can do is
because we can flex laterally and yes we
were also using the muscles of our core
here there are other muscles involved
just as there are pretty much in any
move we make there are other muscles
involved
but the muscles of the back will also
give some lateral flexion and a little
bit of rotation but we know you can do
these movements you can feel all these
other muscles and deep muscles like
quadratus lumborum all these other thing
these are also laterally flexing the
back and a probably more powerful at it
but the muscles of the think group of
the back can also do a better lateral
flexion but their main job is extension
right and this group of muscles then if
we look at if this is a series of
spinous processes here which you can
feel you can feel lateral to that on
either side a good chunk of muscle right
and it kind of it bulges out around here
and that's the deep group that we're
talking about and there are lots and
lots of muscles here and this is where
students can get lost but when you when
you do that and when you extend the back
you can feel those muscles you can feel
that bulge of muscles when you have your
back and that bulge of muscles if you
group all of those muscles together we
call those erector spinae alright so
we've got a lot of muscles in there lots
of different muscles lot of different
groups which we'll talk about in a
minute if we group all of those muscles
together all of that deep group of
intrinsic muscles of the back
we call them erector spinae an erector
spinae is main job then is extension of
the vertical column when you're bent
over that is also lower you you know
what I'm talking about
that's erector spinae these are the
muscles we're interested in today what
we need to do what we need to do next
then is is look at the groups within the
heck within that group
don't give up stay with me it's not so
bad okay
who should we look at so local women if
you're wise we men like that he means we
he's little so this is the erectus
Spinney muscle group here there's
serratus posterior inferior so imagine
that's not there much that's been
removed these are all the superficial
muscles forget them
it's this bulge here now we've got three
layers of muscles and we can think of
those three these three groups of
muscles from medial to lateral and the
most medial group of muscles are called
spinalis or spine eyeless and the spine
arles muscles or spin Arliss still Ali
sounds nicer than just buying spoilers
display nihilus muscles then are the
most medial and for them to be the most
medial then they're going to have to run
between the spinous processes of the
vertebrae so you can see how those
muscles running between the spinous
processes can help with extension of the
bat first spinalis
then we have a long isthmus so long
muscles and the long muscles then a
little bit more laterally and these are
running between the transverse processes
our vertebrae okay and then we have a
Yoko stylist now elio cost Dallas you
can break down any Oh ileum
so the ileal cost Arliss muscles are
coming from you can see these guys here
they're coming from the iliac crest and
the sacrum and they're running up to the
ribs costal right up to the ribs up here
like you can see here how they running
out to the ribs we have spinalis most
medially then Langham it long Isthmus
and then any across stylus over your
three groups that's almost it you have
to think about we have we have groups of
muscles kind of running across a number
of vertebrae alright they're not
attached to the vertebrae next to them
they're running across a few vertebrae
so we've got lots of groups of muscles
overlapping and running up the length of
the vertebral column so we then group
those muscles by whatever region Erin
lumborum if they're in the lumbar region
thoracis if then they're in the thoracic
region and services if they're in the
neck and if they go to the ahead and
head is coupled right home so if they go
to the head then they get called capitis
so we've got
spin analyst long is Imus iliocostalis
here we can see these iliocostalis
muscles so these would be in eco stylish
thoracis muscles do you see what I mean
now not all of these layers extend the
full length of the vertebral column the
longest immersed group for example don't
really go down into the London region so
they don't have a lumborum section so we
have long asommus thoracis long asommus
services and that's almost here that's
almost the whole picture
well spoilers there's more but not for
today's video we've also got some other
models up some other muscles up in up in
the head as I said cathetus which go to
the head right ok so now up in the neck
we can see this muscle here and this is
another muscle of the back and it's part
of that intrinsic group that do play as
you can see the superficial intermediate
and deep layers now do you remember when
we were looking at the half section of
head and we looked at the splendor of
the corpus callosum like and I said
splaining was a roller bandage well for
some reason these muscles get called
roller bandages as well why think anyway
this is a bandaged muscle splenius and
it's going to the head so it's capitis
can you see it's going to the mastoid
process here and you can feel your
masters young area here right and you
can feel your mastoid process here big
lump of muscle pretty important
anatomical landmark and that's where
splenius capitis is going for so you can
imagine the splenius capitis alright
then another muscle as well actually
deep to it it's under here and we can't
see it but there's also splenius
services so another splenius muscle
versus of isis or services because it's
just going between
cervical vertebrae little gap we're
looking through here that that may well
be it what's under there somewhere
and it's running between the vertebra at
about the t3 t4 level not so bad c1 so
it's covering this region here right and
then we have splenius capitis here which
is running from again c6 c7 t1 t2 t3
kind of down here maybe a little bit
higher and then that's running out to
the mastoid process of the head so you
can imagine then that these going
laterally is going to help with rotation
of the neck and head but also like other
like a rector spinae muscles it's also
extending if they work together on both
sides right it's going to extend the
neck as part of that extension of the
back that make sense plus chipiya start
a whole bunch of other muscles they're
all they're all acting together as they
always do but that's all those muscles
do okay so have that last week we looked
at the vertebrae you know all about the
spinous processes and the transverse
processes and allowing the pedicles and
things like that and today we've talked
about many of the deep muscles of the
back of the superficial intermediate and
deep muscles we've talked about the deep
muscles of the back and how those attach
to the vertebrae and work together as
erector spinae to extend the back the
other muscles we talked about in the
upper limb as I said now hopefully the
back doesn't seem too terrifying or too
complicated to you anymore
even if it did in the first place there
is a lot going on here but just think
about those functional units but
unfortunately there is more this is got
a block that comes out so there are also
there's an even deeper layer of the
muscles of the back now you might read
different descriptions and different
textbooks for Groovy's these groups of
muscles differently don't worry about
that we would you like to describe
things in different ways but while I was
talking about
erector spinning being part of the deep
muscles of the back which is one way of
describing them and being part of the
intrinsic group of muscles of the back
there's an even deeper layer of muscles
called the transverse Oh spinal muscles
and these guys are really really deep
and they run between the processes of
pretty much adjacent vertebrae and they
do a whole bunch of other things these
guys are involved in back pain back
spasms that sort of thing whole battle
will come back to those guys next week
to chunk by chunk by chunk and then
you'll understand the anatomy of the
musculature or the musculature at the
back all right well yeah there is a lot
here
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