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 different difficulties and they give you
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if you don't like it get your money back 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