hello everyone thank you for joining me in this discussion of the movements of the synovial joints
and so when we talk about each individual synovial joint or some of the major ones say
TMJ, elbow, shoulder, etc. we're going to talk about the actions that can occur at these joints because
that's really important you can see if there's some loss in range of motion that type of stuff
that can be clinically as well as functionally important so we need to understand what those
movements actually mean we're going to begin with the discussion of what is anatomical position
and then we're going to touch on some of the big picture highlights of the six types of synovial
joints we're not going to get into nitty gritty details of each one because that's
going to come up in later discussions all right so before we do this though we really need to
talk about what anatomical position is and this has been introduced to you but i want to bring
it back up here again because a lot of these movements you have to understand that that's
being discussed with anatomical position in mind and so not only musculoskeletal is
this important but this is true throughout the entirety of the discussion of anatomy
so what is it okay so this individual is really showing you anatomical position an individual is
standing their head is facing forward their toes are facing anteriorly those things make sense
and the feet are parallel but one thing that sometimes doesn't make as much sense is that
these palms are going to be facing anteriorly and that's not really a natural position that we stand
we don't naturally stand with our palms facing anteriorly but the reasoning behind this is that
the bones in the forearm the radius and the ulna are not crossed over one another at that point
if your palms are facing anteriorly the radius and the ulna are going to be parallel to one another
and thus that's anatomical position so all these discussions that we're going to have i want you
to be thinking about from anatomical position and a few just reminders in terms of planes
because this is important if you think the median plane this is going to this is kind of going right
down the midline region it's going to split the body into right and left halves and then you can
have multiple sagittal planes that are kind of on either side of that so think a vertical plane here
a coronal plane or frontal plane you'll hear it either way will split the body into
anterior and posterior parts okay so some of these actions you'll be thinking about occurring in more
of a frontal plane or say more of a sagittal plane and then of course the reminder of the
transverse or axial plane excuse me will split the body into superior and inferior parts and you can
have multiple transverse or axial planes similar with the frontal planes and sagittal planes
okay so let's start with flexion and extension because typically this is one of the
easier ones to conceptualize and this typically occurs in a sagittal plane okay i think well
the sagittal suture is going to be located here splitting body into right and left halves
and flexion literally means flex means to bend so what we are doing here is
decreasing the angle between articulating bones i always think thinking around the elbow joint
region that's one of the easiest to conceptualize flexion think about you're reducing the angle
right here in this particular joint and extension is to stretch out it will
increase the angle between articulating bones and oftentimes extension is a restoration to
anatomical position but not necessarily so and in fact you can hyperextend past anatomical position
so most synovial joints of the body can flex and extend so the simplest ones say
like in terms of a hinge joint that is going to only be capable of flexion and extension
abduction and adduction and often you'll hear me spell out ABduction or ADduction because
these two terms sound so similar this typically occurs in that frontal plane or coronal plane
so splitting that body into anterior and posterior positions and abduction i'm going
to stand up for this one abduction you're moving away from the body and adduction you're moving
back towards the body and you can even come kind of past anatomical position
so abduction is typically away from the midline and then you can think of i'm adding ADDucting
back to the body all right so that's abduction and adduction
now if you can flex, extend, abduct, and adduct or say flex, abduction, extension, adduction or in the
opposite order if you can do those four movements you can circumduct and really all this is is just
a complex angular movement that involves these actions happening in a sequential motion and
allowing for an individual to circumduct so quite you know there's going to be many of the types of
synovial joints that can do these four types of movements and anytime you can do all four you can
circumduct I see I can even do it here with this joint but oftentimes we think of it more we know
say with the shoulder joint or with the hip joint but some of those smaller joints can do it as well
now rotation is when a bone revolves around its own longitudinal axis and this one is a little
bit more conceptually difficult so think about pivoting or rotating one of the ones that kind
of comes up first in mind to me is that the atlanto-occipital joint or the one that's
associated with the head the atlanto-axial joint as well this is going to allow you to say no
so you think about there's that rotation of C1 and C2 around one another those cervical vertebrae to
allow me to say no okay that's rotation now when we're thinking about the appendicular skeleton
this can occur in certain joints as well some of the more complex or more freely movable joints
and you can have this is off this type of rotation is often referred to as medial
or internal rotation i always think of flexing the elbow that kind of allows
you to conceptualize what's going on the shoulder joint so if you medially rotate
this portion of the humerus is going to move more medial or internally if you laterally rotate
or externally rotate that's going to kind of move away or move more posteriorly there
okay so you have medial rotation or lateral rotation and generally the terms internal or
external are used more in term used more clinically so if you hear this more in
a clinic whereas medial and lateral rotation are more anatomical terms
all right so let's real quickly touch base in terms of some of these joints so the most
freely movable are going to be your ball and socket joints so you have literally a ball
type articulating surface of the bone and a socket portion the hip
joint is a great example and then the shoulder joint is going to be the most freely movable
of the joints and so these types of joints are capable of flexion, extension, abduction,
and adduction as well as both medial and lateral rotation so really capable of all those actions
condyloid joints as well as saddle joints are going to be capable of flexion, extension, abduction ,
and adduction but not rotation okay so condyloid and saddle joints really the best example of a
saddle joint is between the trapezium and the car the first metacarpal in the thumb region
condyloid joints are found kind of throughout the body but one of the best examples is at the
wrist joint where that radius of the forearm is articulating with that proximal row of
carpal bones so that's a condyloid joint and these are really named just based on
the shape of those articulating bones so say with the saddle joint one of those
bones looks like a saddle and the other bone kind of sits within that saddle
all right a hinge joint is only capable of flexion and extension
kind of the main example of that here is that this elbow joint or the humero-ulnar joint
the knee joint is also an example of a hinge joint it's a modified hinge joint so there's
a little bit more that can occur there but the main action is going to be flexion and extension
pivot joints are going to be capable of rotation so between like i was mentioning before the C1 and
C2 vertebrae allowing us to say no though that's going to be an example of a pivot
joint but say like C1 and C2 you're not really having much flexion extension occurring there
and then lastly one of the more simplistic joints but very important in terms of really allowing
other joints surrounding it to have full range of motion are what's referred to as plane joints and
the articulating surfaces of plane joints are going to be relatively flat and literally this
is just allowing kind of a sliding and gliding movement to occur between the articulating bones
so as mentioned these are not huge movements in terms of what's happening there but that movement
and those bones will allow say the shoulder joint to be able to move a bit more and we'll
talk about those specific examples of plane joints when we get to some of those more important ones
all right excellent so this isn't the first time you've heard you're going to hear
the six types of synovial joints when we talk about each one of the more complex or
relevant synovial joints we'll talk about which type of synovial joint it is as well
excellent so that leads us to our question all right movement away from the midline in the
frontal or coronal plane that plane that splits the anterior and posterior portions of the body
is which type of angular movement okay so pause the video
and when you're ready let's talk about this so the stem here really is key so movement away
from the midline in that frontal and coronal plane is which type of movement all right so
abduction i like the sound of that we'll come back to this one adduction is movement
towards the midline so that's not right flexion and extension this typically occurs
in the sagittal plane so this isn't correct and circumduction is really this complex movement of
these two movements along with these two movements so that's not the correct answer so ABduction
or abduction is going to be the correct answer here so abduction a is the correct answer
all right so if you if it is possible for you at some point to kind of work through these
actions with yourself or with a partner to kind of act out that can be really helpful in
terms of conceptualizing these and again this is something that's going to come up quite often
in terms of being able to understand what flexion, extension means what abduction, adduction,
circumduction as well as a little bit more complex but also important rotation
thank you so much for your time and attention here as always we've had
if you have any questions please reach out thanks for your time