this video was sponsored by kenhub more on them at the end of the video hello
and welcome my name is patrick and in this video i'll teach you some of my
tips and tricks for remembering all of the skeletal muscles of the abdomen that
you would see in an anatomy class and to make this lesson more manageable for
beginners i'll present the list in smaller chunks of four to eight muscles
you can find a list of the sections and time stamps in the description below and
with that out of the way let's get into the muscles
the first chunk is the abdominal muscles and you have four big ones to remember
here luckily they all follow that straightforward and predictable naming
convention what most people know is the abs is the rectus abdominis those showy
six-pack muscles it uses the rectus nomenclature meaning a straight muscle
plus abdominis which is self-explanatory now the rectus abdominis is actually
surrounded by a sheath of connective tissue and there's another muscle in
that sheath called the pyramidalis it's triangle shaped attaching to the pubic
symphysis and other parts of the pubic crest if we peeled away the rectus
abdominis we'd find a layer of muscle that wraps all the way around the
abdomen called the external oblique and under that the internal oblique the
layers are obvious giveaways the internal is deep to the external but you
might not always know which layer you're looking at fortunately you can use the
direction of the muscle fibers to tell them apart the external oblique fibers
run this way and look like they're pointing up while the internal oblique
fibers point down to remember this i imagine an extrovert and an introvert at
a party the extrovert is looking up and happy while the introvert is like
looking down at their drink just like the external obliques fibers point up
while the internal obliques fibers point down the final muscle in the abdomen is
the transverse abdominis it's called the transverse abdominis because it wraps
around the entire abdomen literally starting on one side of your vertebrae
wrapping all around your abdomen attaching to the ribs and pelvis and the
other side of your vertebrae this muscle is a big wide muscle that transverses
your entire abdomen on the back side of the abdominal wall is the quadratus
lumborum a name that has the memory device built in we know that quadratus
means square shaped and lumborum is the region the lumbar region as we move on
to the back muscles your saving grace will be knowing your vertebrae skeletal
anatomy so let's do a quick review here's your run-of-the-mill vertebral
bone this big piece in the center is called the spinous process and these
pieces on each side are called the transverse processes so if you see
spinous or transversus in the muscle name you can start thinking about
attachments to the spinous or transverse processes respectively another quick
note some muscles are big muscles that span the entire spinal column while
others are multiple tiny muscles between each vertebrae i'll do my best to make
it clear which are which the most familiar is probably the erector spinae
the group of muscles that straighten the spine as the name implies at the gym the
erector spinae is usually illustrated as two column-shaped muscles that run up
your low back but in reality they're a group of muscles just like how when
people say the quadriceps they're referring to four muscles the erector
spinae group is three muscles the iliocostalis longissimus and spinalis
here's how i think of it all of these muscles go superior inferior and they
all have the common goal of straightening the spine so we know that
they'll run parallel to each other so once you find those long bundles of
muscles you just need to label them from medial to lateral the most medial is the
spinalis and remember how i said that the attachment on the vertebrae helps us
find the names well the spinalis attaches to the spinous process of the
vertebrae the spinal process is dead center so it's as medial as it gets
lateral to that is the lungismus the thickest and longest of the erector
spinae muscles branches of this muscle literally run from the pelvis to the
base of your skull and because it's so long it's called the long ismus finally
the iliocostalis has one of those intuitive names it connects the ilio and
costal or the ilium to the ribs you can see from its origin on the pelvis how
lateral this thing is so from medial to lateral the erector spinae is the
spinalis lungismus and iliocostalis but the erector spinae has one more detail
before we're done with it each of these long muscles are made of tinier segments
like the iliocostalis has three sections that line up with each region of the
spine lumbar thoracic and cervical having this kind of segmentation allows
us to move sections of our back independently like if the erector spinae
didn't divide further every time we straightened our lower back we'd also
crane our neck backwards the erector spinae group is the big superficial
muscle group but underneath it lies the more delicate transverso spinalis group
made up of the semispinalis multifidus and rotators this is dumb but i remember
this group because the names sound like deliciously italian the first item on
our menu is the semi-spinalis group now we already learned about the spinalis
muscle which connects spinous processed spinous process but these are
semi-spinals because they connect the spinous process to something else the
semispinalis cervicis for instance originates on the transverse processes
of the upper thoracic vertebrae and inserts on the spinous processes of
cervical vertebrae the semi-spinalis thoracis does the same thing just lower
on the spine it originates on transverse processes that inserts on spinous
process then there's the semi-spineless capitis which originates on the
vertebrae but inserts on the back of the skull the next item on our little
italian menu the multifidus is one of those muscles made up of tiny segments
that span the length of the spine from sacrum to skull it sits in that little
valley made by the transverse and spinous processes and it's mainly there
to stabilize the spine during other movements i remember this one because
it's made of multiple tiny muscles hence multifidus and even deeper than the
multifidei are the rotator muscles they connect the transverse process of one
vertebrae to the lamina and spinous process of the vertebrae above it these
muscles are so small and deep that they stabilize the spine more than they
rotate it but because they're so horizontal compared to the other long
erector muscles i can always remember that these should be my rotator muscles
as the name implies now depending on which anatomy book you have you might
only see the rotator thoracis presented they're the most developed and easiest
to find but rotators colli in the neck exist as well as the rotator's lumborum
in the low back okay we're done with the italian menu now on to dessert the
interspinalis are exactly what they sound like tiny muscles between the
spinous processes of the spine many people don't have them in their thoracic
spine so you'll almost always see them in the cervical and lumbar spine as for
memory devices that prefix inter is doing the heavy lifting here it tells us
that these guys go between the spinous processes as opposed to over them like
the larger spinalis muscle likewise the inter-transversary eye are found between
the transverse processes of the same vertebrae for the same reason inter and
transverse as we move on to the thoracic wall you'll hear a certain latin term
repeated a lot here costal in anatomy costal refers to the ribs so the
intercostal muscles refer to muscles that go between the ribs hence
intercostal you have two sets the external intercostals and internal
intercostals both of which connect rib to rib as the name implies the internals
are deep to the externals fair warning though some professors throw in the
innermost costals as a third deeper layer of muscles but you should be fine
knowing just external and internal intercostals separately from those
muscles are the subcostal muscles and here's where those prefixes come in the
intercostals went between the ribs but the subcostals go under the ribs
specifically they're found on the inside surfaces of the backside of the ribs
closer to the spine than the skin the last muscles using that costal latin
root are the levator's costarum in the back they attach the ribs to the
thoracic vertebrae above them and as the name implies when they contract their
position lets them lift the ribs next up a muscle with a shape right in the name
the serratus posterior superior and serratus posterior inferior serratus
refers to the serrated shape this kind of jagged sawtooth pattern it's the
serratus posterior since there's another big serratus muscle around the ribs the
serratus anterior which we'll talk about in a little bit finally there's a
superior muscle and inferior muscle to indicate their position they're
relatively far apart so it's pretty clear which one is superior and which
one is inferior one pro tip the serratus posterior superior and rhomboid muscles
are both in similar spots so if you find yourself confused remember the naming
conventions the serratus muscles have that jagged appearance while the
rhomboids will have a more geometric appearance if we return to the front of
the ribs we find the transversus thoracis a group of muscles on the
inside of the chest wall making this cool diamond shape around the sternum i
remember this one because it looks like it transverses or covers the entire
front of the thorax finally the diaphragm this muscle is so unique and
interesting that i never really needed a memory device for it it's this wide
muscle that attaches all over the inside of your body it's your main muscle of
breathing and separates the thoracic cavity from the abdominal cavity this
muscle is so essential to our daily life give the diaphragm the respect it
deserves and memorize it on its own no memory device is required now these are
just the tricks that i personally use to remember these muscles but if you want
another great resource for learning anatomy then you need to check out
kenhub i use them all the time when researching and writing these videos and
for this series in particular their written articles and atlas of muscles
have been extremely helpful in refreshing my knowledge of some of those
deeper smaller muscles they've also got an enormous library of in-depth videos
about muscles histology vasculature nerves and everything else you'd need to
know in anatomy class all those beautiful illustrations that you saw in
this video came from them and in addition to their library of content i
also love kenhub's quiz feature they allow you to build custom quizzes with
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if you wanna see the next video in the muscle memorization series then check
out this playlist here otherwise subscribe leave a like on the video have
fun be good thanks for watching