hello anatomy colleagues this is dr alsup and in this video we will be discussing the two
main classification schemes for joints so the two ways to classify joints are structurally
which is where we will spend the majority of the rest of our time discussing joints as well
as functionally which we will introduce here and will be a much smaller focus in subsequent videos
we will also discuss the term ligament or ligaments if we're talking plural as these
are so important to joints overall and these often play a role in how we actually describe a joint
so as we mentioned the two major ways to describe joints are structurally which
will describe the tissues that will actually connect the bones so kind of the key here
is what tissues are are connecting the bones and where that where it's located remember
there will be some connective tissues between the bones always bones don't actually touch
there will also be functional classifications and these are really more describing the degree
of movement permitted at a joint so of the functional classifications there are three types
the joints that are immovable so no movement whatsoever these are syn arthroses
and amphiarthrosis is a slightly movable joint and when i say slightly movable i definitely mean
that sometimes the movement is so slight that it's not even perceivable and lastly typically
when we think of a joint we are thinking of diarthrotic joints which are freely movable
all synovial joints which is a structural classification are diathrotic diathroses come
in a variety of shapes and permit many different types of movement and to varying degrees
in terms of structural classifications there are two basic ways that bones will
connect with one another to form joints the first is the simplest
these are the simplest the bones will be attached to one another
by a solid sheet and that's that's key here a solid sheet of connective tissue so no space
between the bones so you can see that really well here you're gonna have a bone here a bone here and
in between you have a solid sheet of connective tissue that's actually connecting the bones
what can differ in this classification scheme is the type of connective tissue which makes
up the connections is it going to be dense irregular connective tissue like you have
in fibrous joints or is it going to be cartilage like you have in cartilaginous joints the other
way that joints form is a bit more complex but it's actually the most common type and this has
bones being joined by a connective tissue capsule which you can see on the outer ends of the bone
and so that's what is actually connecting the bones and then in the middle there will
be this lubricated cavity which is not composed of a sheet of connective tissue it's in essence
a slight space between the bone so not that solid sheet of connective tissue
and this allows more possibilities for movement and these types of joints are called synovial
joints which is where we are going to spend the majority of our time in our joint discussions
each one of these structural categories fibrous cartilaginous
and synovial will have their own video so we'll we will talk in more details there
but before we finish here let's talk a little bit about ligaments ligaments are going to connect
bone to bone which is different from tendons tendons will connect muscle to bone and ligaments
are composed of dense regular or dense irregular connective tissue depending on the source you may
see different things but what they look like and where they are located can vary wildly and
widely and ligaments are identified how they're identified can vary quite a bit by discipline
and sometimes even within a discipline for our purposes we are going to describe ligaments
that actually bind the bone so what we saw here with that sutural ligament so what is actually
binding the bones those solid sheets of connective tissue between the bones those will be intrinsic
ligaments and those that are playing a supportive role those will be referred to as extrinsic and
these are particularly important with synovial joints sometimes these ligaments can be located
as part of an articular capsule or even within an articular capsule and these are often referred
to as capsular or intracapsular dependent on their location and sometimes the ligaments are
completely separate from the articular capsule but will support support the joint overall and
will help prevent unwanted movements and those are referred to as extra capsular
so definitely more to come on ligaments we will discuss specific ligaments with each
joint each of the main joints that we will discuss later on all right so that was some
good fun and introducing joints and let's review a concept regarding those functional classifications
so question functionally i have it right there in the the questions then functionally
a freely movable joint is described as what a an amphiarthrosis b a diathrosis or c a synarthrosis
pause the video if needed and when ready i hope you have landed on b diathrosis
being the correct answer amphiarthroses are very slightly movable but certainly
not described as freely movable whereas a synarthrosis is immovable so definitely not
freely movable all synovial joints will be diarrhotic or freely movable so that
that um relationship between free movement and synovial joints is a really important one that
is where we get those typical movements of the body that we often think of all right so that is
it for these concepts thank you for your time and attention here and have a great rest of your day