hello anatomy colleagues this is dr alsup again and in this video we will discuss the
movements that can occur at synovial joints and this discussion will lead into our next video
which will talk about the types of synovial joints and one of the main things we'll talk
about there are what types of movements can occur so they all kind of come together and
intermingle in terms of topics of discussion so the focus of this discussion will be the
angular movements for the most part or causing an increase or decrease in the angle between
articulating bones and we will spend some time also discussing rotation which has a bone
rotating along its longitudinal axis but before we get into these different types of movements
it's important we understand what anatomical position is this is a key
concept in anatomy as a whole anatomical position is the standard position for reference for any
description of movement or also importantly any description of anatomical structures
so when thinking of anatomical position it becomes easier to visualize and organize structures
without also having to factor in different movements or if the individual is lying down on
their back or on their stomach you can always come back to anatomical positions in your descriptions
in anatomical position an individual is standing and facing the observer like we have in this
individual right here so eyes are facing forward the feet are also facing directly forward and flat
on the ground and it's the upper limbs that may seem a little counterintuitive
the upper limbs are going to be to the side but key here is that the palms
of the hand are facing forward or anteriorly which is not a particularly natural stance
right we don't typically stand like that but the reason for this position
is that in this particular position with the palms facing forward the bones of the forearm
or the radius and the ulna are parallel to one another so they're not crossing over one
another like you would have if so the palms were facing towards the posterior portion or the back
so all movements and directional terms we will use throughout this course so not just
in the musculoskeletal section will be based around this anatomical position so spend some
time making sure you understand this i cannot reiterate enough how this particular position
or this particular reference point will come out throughout the entirety of this course
here's another area or another slide that i would also spend a bit of time on making sure
you understand and part of our understanding of these movements and some of our other
descriptions and different parts of the course will be understanding the planes of one's body
and these planes are imaginary planes as in this is something that we use for description purposes
and the planes will intersect the body when it is an anatomical position so let's review these
the median plane which i am drawing an arrow to is a vertical plane and it will pass longitudinally
through the body's midline so the median plane is exactly what it sounds like it is running right
down the middle of the body and it will divide the body into right and left halves
sagittal planes which you can see a sagittal paint plane being drawn right here sagittal
planes are similar in that they are vertical planes as well they will pass through the body
as well but these will be parallel to the median plane so sometimes that median plane
is referred to as the median sagittal plane but sagittal plane can be kind
of on any side on either side of the median plane running parallel to the median plane
the frontal or the coronal plane which we can see here is going to run also vertically
and it will pass through the body at kind of right angles to the median plane
but it will divide the body into anterior and posterior parts or anterior kind of being towards
the front and posterior being towards the back and lastly transverse planes or horizontal planes will
pass through the body perpendicular to any of the vertical planes so it will divide the body
into superior and inferior portions the superiors towards the head inferior think towards the feet
okay so we needed to understand these concepts before even understanding these concepts of
these planes before really understanding some of the movements that we're about to discuss
and like i said this slide as well as this past slide right here
is really found these two are foundational concepts that will come out throughout the course
so let's start with one of the more intuitive or two of the more intuitive movements
that can occur at synovial joints and these are called flexion and extension and these will occur
in a sagittal plane so sagittal plane now flexion means to bend it literally means to bend and this
will cause a decrease in an angle between the articulating bones okay so you can see flexion
here flexion think about putting your chin towards your chest you can flex the hip
and flexion typically occurs in an anterior direction but not
always which we'll see with the knee joint extension is kind of the opposite motion
this will be an increase in the angle between articulating bones and often you
will have a joint returning to anatomical position after being flexed with extension
now extension can extend haha see i use that twice there so extension can extend past anatomical
position even further increasing the angle between the bones and this can be done purposefully and
safely with many joints if you think about being in anatomical position and then kind of tilting
your head backwards you can do that and you can do it safely that's hyperextension but hyperextension
can be a type of movement that is not meant to happen like in the knee or in the hip joint a
little hyperextension is allowed but too much can be damaging and oftentimes the arrangement
of muscles and ligaments really help to reduce the amount of hyperextension possible lateral flexion
or lateral bending which is often referred to as does not occur in the sagittal plane
as most flexion extension does it will occur in the frontal coronal plane and this occurs at the
intervertebral joints and will allow you to move your trunks or your trunk to one side or the other
the paired actions of abduction and adduction also occur in the frontal or coronal plane and you
may hear me say a b duction or a d duction just because sometimes my enunciation leaves something
to be desired so sometimes i really try to get my point across and accentuate the a b or the a d
all right and you can always think of adduction as adding back to or put back towards the the body so
abduction or abduction is typically a movement away from the midline or away from the body
and adduction as mentioned is movement back towards the midline and sometimes
even past the midline so you can think about your upper limb
it can head back towards anatomical position in the midline it can even go a little bit further
the midline of the body is not used as a point of reference for the digits of the hands and the
feet but we will discuss those specifics when we talk about those specific joints
now if a joint can flex extend abduct and adduct that joint can also circumduct which is
a complex angular movement that involves these actions that i just discussed and what happens
with circumduction is the distal end of the body will move in a circular motion so if a
particular joint is capable of these four types of movement it is also capable of circumduction
lastly let's finish our discussion of movements with rotation and rotation is typically the most
difficult of the actions to conceptualize rotation occurs when a bone will revolve around its own
longitudinal axis i think one of the easiest to conceptualize forms of rotation is turning your
head from side to side as if you are vigorously saying no to something so think about turning your
head from side to side that is a form of rotation but when we're talking in terms of the limbs
rotation is defined relative to the bone's midline and we use the terms medial and lateral rotation
medial sometimes referred to as internal rotation is the movement that occurs when the anterior
surface of a bone is turned towards the midline so think that anterior surface will head that way
whereas with lateral or external rotation that anterior surface
will will rotate away from the midline or more laterally
there are other special movements that occur at specific joints and we will talk about those
with the individual joints one point i want to get across before we finish here is that rarely
does a total action event just involve one type of these movements that we talked about
most activities will involve more than one type or numerous types of movements
if not all of the ones we describe so sometimes it seems as if we are talking about these movements
in a vacuum but think about walking or swimming or climbing you're not just flexing the whole time to
make that activity happen you're flexing you're extending you're abducting your ad abducting and
adducting you're rotating so oftentimes action events will be a complex of all the movements
that we just discussed or many of them all right let's review a concept together here
the question is movement away from the midline in the frontal or coronal plane
is which type of angular movement abduction adduction circumduction extension or flexion
so in the stem i am honing in on away from the midline as well as
the frontal or coronal plane those two are pretty descriptive of one of these action one of these
movements that we have down here which hopefully you are thinking that that is abduction okay i
think adduction is moving back towards the midline adding back towards the midline
so um even though this also occurs in the frontal plane so abduction is the correct answer
yay great job all make sure you go back and answer those learning objective questions
that we have on that second slide based on the concepts we just discussed
and if you have any questions or you can't fully answer one of those questions please feel free to
reach out to me thank you for your time and attention and have a great rest of your day