Articulations
The “Moving” Part of Anatomy!
Introduction
• Many major sports, activities
and hobbies require us to be
able to move around
• These movements define us as
human because we have a
unique ability to move in the
animal kingdom
• There is almost no parallel of
fine and large movement in the
animal kingdom
https://www.youtube.com/watch?v=wNG0QJw7-4A
Introduction
• However movement does come
at a cost
• It means that things that protect
and are stiff and rigid will have
to be able to bend
• Since there are transitions
between areas that are designed
for support and areas that are
designed for movement,
weaknesses can occur
https://www.youtube.com/watch?v=r_wPOfTGegA
Introduction
• While the previous slide
incorporated several different
major impacts, small impacts
can damage parts of the body
• Articulations, also known as
joints, can be damaged from
relatively small impacts or
repeated motions
• This often presents as stubbed
fingers, sprained ankles and
swollen joints
https://www.youtube.com/watch?v=lgNttdd7UIc
Types of Articulations
• There are two different
categories of joints
• The first category of joint defines
it based on how much the joint
moves
• Once that has been determined,
the second category further
defines the joint based on the
features that make it up
Types of Articulations
• There are three different types of
joints that are based on their
movement
• A synarthrosis is an immovable
joint
• Stays There
• An amphiarthrosis is a slightly
moveable joint
• Almost There
• A diarthrosis is a freely moveable
joint
• Defiantly There
Types of Articulations
• Once you figure out what type of
joint it is, you have to figure out
what type of material the joint is
made of
• A bony joint has the ability to
connect two bones without
anything in-between
• A fibrous joint has no joint cavity
and are connected by fibrous
connective tissue
• A cartilaginous joint is connected
entirely by cartilage
• A synovial joint has synovial fluid
surrounding the joint
Types of Movement
• Articulations provide the ability to
move many different ways
• The movement can happen in several
different ways
• Gliding movement is movement from
the base of the articulation
• This is good but it does not happen often
in the body
• Angular movement is when the angle
created from the base of a joint
changes
• Rotation happens with the angle of
the base stays the same, but the
position of the appendage changes
Types of Movement
• Try this…
• Put your pencil or pen tip on the
center of the cross in your notes
labeled gliding movement
• Use your massive brain power to
create a scenario where you
create gliding movement
• If you are having trouble with
this, think about moving from
the base
Types of Movement
• Ok smarty-pants…
• Now put your pencil tip on the
cross labeled as angular
movements
• Now try to make an angular
movement
• Hint: This is movement that
changes the angles of the base
Types of Movement
• Last one…
• Put your pencil at the center of
the cross labeled rotation
• Make the pencil rotate
• … But don’t change the base
angle
Synovial Joints
• Synovial joints are diarthoses
(defiantly there) that are
surrounded by a joint capsule
• A joint capsule is a double
layered sack that contains
synovial fluid
• The joint capsule functions as a
protection, nutrient distribution
medium and a shock absorber
for the joint
Synovial Joints
• Synovial joints do not have
bones that touch
• The bones are capped in
articular cartilages that protect
the bones from rubbing on each
other
• The cartilages never actually
touch because there is always a
thin film of synovial fluids that
separate them
Synovial Joint Accessory Structures
• Many synovial joints have
accessory structures that are
used to aid function within the
joint and protect it from harm
• A meniscus is a crescent shaped
pad of fibrocartilage located
between bones
• Menisci allow for better flow of
synovial fluid, divide the joint
cavity or allow for variations in
the shapes of surfaces
Synovial Joint Accessory Structures
• Fat pads are localized masses of
adipose tissue covered by
synovial membrane
• They commonly surround the
joint
• Because a joint can move, it
often has different shapes to it’s
cavities
• These pads fill the spaces that
are created when the joint
moves
Ligaments
• Inside of or outside of the joint
capsules ligaments support,
strengthen and reinforce
synovial joints
• Ligaments connect bones to
different bones
• These ligaments are very
important to maintaining the
structure of the synovial joint
Ligaments
• Ligaments are dense regular
connective tissue
• This means that they are very
strong in one direction because
all of their fibers run in one
direction
• This is why ligaments are often
found in groups
• They cover the stresses from
many different angles is synovial
joints
Ligaments
• While ligaments are strong, they
are not invincible
• A sprain is a situation where a
ligament is stretched to the
point where some collagen
fibers are torn but the ligament
is still intact
• A torn ligament is where the
ligament separates from itself or
the bone completely
Video
• A full ACL reconstruction surgery • https://www.youtube.com/watc
h?v=M-FQGMPfGac
• Take a moment to think do I
want to watch someone have
ACL reconstruction surgery
• If you do not want to see
incisions and bone drilling please
do not watch the video
Tendons
• Tendons connect muscles to
bones (or other structures like
the eye)
• While they are not part of the
articulation, they often times are
responsible for the force and
range of motion within the
articulation
Tendons
• Just as an example the tendons
in the rotator cuff provide much
of the support for the shoulder
joint
• The movements of this
diarthrosis (defiantly there) are
limited by the arrangements of
the tendons
• Try this out by stretching your
arms!
Bursae
• Bursae are small fluid filled
pockets of connective tissue
• These are found connected to
and around synovial joint
cavities
• These bursae are lined by
synovial membrane tissue
• Each one contains synovial fluid
Bursae
• These bursae are generally
designed to keep tendons and
ligaments from rubbing on other
tissues
• They serve as a buffer that helps
protect the ligaments and
tendons from damage
• This makes their job vital in a
synovial joint
Bursae
• Bursae can be broken due to
stress or damage to the synovial
joint
• Generally it leads to a large
amount of swelling as the
synovial fluid leaks out
• Also they can develop in non
synovial joint tissues if there is
an excessive amount of rubbing
or pressure
Synovial Movement
• Synovial Joints can move in very
interesting ways
• These joints can make a wide
variety of complex movements
that make up the movements of
the body
• Since synovial joints vary greatly,
there are many different types of
movements that can be
performed
Synovial Movement
• The first basic type of movement is
flexion and extension
• Flexion is the movement where
articulating bones decrease their
angle
• Extension is the movement where
articulating bones increase their
angle
• Hyperextension is movement past
standard anatomical position
• This can be seen in the elbow and
neck
Video
• Hyperextension could be
normal…
• https://youtu.be/5MayaRACKso
?t=33s
• Or not normal…
• https://www.youtube.com/watc
h?v=eGIQ4AzzXnE
Synovial Movement
• However not all movement is
regulated to linear movements
• Abduction is movement away
from the center line of the body
• Adduction is movement towards
the center line of the body
• These movements can be seen
in the hand
Synovial Movement
• Sometimes there is a mixture
between angular movement and
rotational movement
• Circumduction is the term given
when a limb moves in a circular
direction
• This would be similar to drawing
a big circle on the whiteboard
without moving the wrist or
elbow
Synovial Movement
• Rotational movements are often
seen in the body
• If the head rotates to the left or
right side of the body it is a right
rotation or left rotation
• If a limb rotates to the outside of
the body we call it a lateral
rotation
• If a limb rotates to the inside of
the body we call it a medial
rotation
Synovial Movement
• The rotation between radius and
ulna are a special case
• During pronation the radius
moves across the surface of the
ulna and the hand moves
opposite of anatomical position
• During supination the radius
moves back across the ulna and
the hand moves to anatomical
position
Ball and Socket Joint
• There are several different types
of synovial joints
• Each has a function and purpose
that helps the human body
move and articulate in the
natural world
• Each type has strengths and
advantages
• At the same time each type has
drawbacks and weaknesses that
are important to understand
Ball and Socket Joint
• Ball and socket joints are joints
where a rounded bone fits into a
concave bone
• The hip and the shoulder are
good examples of this type of
joint
• Ball and socket Joints allow for
maximum range of movement
Ball and Socket Joint
• The downside of a ball and
socket joint is that they rest
inside of a concave bone
• The rounded bone can migrate
from the original location
• When this happens we call it a
dislocated joint
• This can happen when playing
contact sports or during trip and
fall events.
Video
• http://on.aol.com/video/howto-relocate-a-dislocatedshoulder-326724540
• https://www.youtube.com/watc
h?v=GLEklCEKyx4
• Always locate medical
professional help!!!
• If no medical help is around,
there are ways to place your
shoulder back in the socket
before being able to go see a
doctor
• This is not advised if you can
make it to a doctor in any
capacity!!!
Hinge Joint
• A hinge joint is the area where a
rounded bone meets a bone that
curves inward
• These types of joint are surrounded
by ligaments and tendons that
prevent side to side motion
• This makes them able to articulate
in one direction, but prevents
damage from other directions
• The elbows and knees are great
examples of this
Hinge Joint
• Since you have two bones that
are meeting and making a
repeated motion, there can be a
large amount of ware and tare
over a lifetime
• When the protection inside of
the synovial joint wears down, it
is known as arthritis
• This can often be painful and
sometimes debilitating
Video
• https://www.youtube.com/watc
h?v=FVCtXxd_P1c
• http://www.businessinsider.com
/cracking-knuckles-arthritisscience-2014-12
Gliding Joints
• Gliding joints are created where
there are two flat bones that
meet and move
• These may also be called plane
joints
• These types of articulations
happens when a gliding
movement is seen
• The wrists and ankles are
excellent examples of gliding
joints
Gliding Joints
• Because these joints are gliding
joints there are many different
things that can affect how they
move
• Any small defect or deformity in
the area of the gliding joint will
create pain and damage as the
bones move over each other
• Things like fractures, deformed
disks and bone spurs can cause
debilitating pain
Saddle Joints
• A saddle joint is when one bone
that is shaped like a saddle
glides along another bone
• This provides a joint with a large
amount of movement that is
relatively stable and safe
• It can move in almost every
single direction except for where
the concave surface of one joint
interacts with the convex surface
of the other
https://youtu.be/0cYal_hitz4?t=6m8s
Saddle Joints
• Saddle joints can be seen in
different parts of the body
• The most famous saddle joint is
your thumb
• Because of how the bones glide
over each other, there is
movement in almost every
direction
• However the “saddle” prevents
it from left and right rotation
Pivot Joints
• Pivot joints consist of the
rounded end of one bone fitting
into a ring formed by the other
bone
• This gives a good amount of
rotational movement
• However it also supports the
joint by holding it tight within a
bone
Pivot Joints
• Pivot joints are seen in a few
different capacities throughout
the body
• A very easy one to recognize is
the joint between C1 (The Atlas)
and C2 (The Axis)
• The Atlas holds The Axis within a
bone and ligament structure and
allows for rotational movement
while supporting the head
Condylar Joints
• The condylar joint (aka ellipsoid
joint) is formed when an oval
head of one bone rests within
the elliptical cavity of another
• This gives a large range of
motion, however it limits motion
in the rotational direction
• This is because the oval and
elliptical cavity will prevent
rotational movement
Condylar Joints
• The condylar joints are seen in
the fingers
• The joint between the
metacarpals (2-5) and the
proximal phalanges (2-5) forms a
condylar joint
• This allows your fingers to move
in almost every direction except
for rotationally
The Shoulder Joint
• The shoulder joint
(glenohumeral joint) permits the
greatest range of motion of any
joint
• Since it allows the most motion,
it is also one of the most injured
joints in the body
• Stability must be sacrificed to
create mobility
The Shoulder Joint
• The ball in this joint is the head
of the humerus
• The socket of this joint is made
up the glenoid cavity of the
scapula
• The head of the humerus sits
inside of the glenoid cavity and
can articulate in a wide range of
motions
The Shoulder Joint
• The shoulder is held together by
five ligaments that hold various
parts of the humerus, scapula
and clavicle together
• The muscles that hold the
shoulder together do more to
stabilize the shoulder than the
all of the ligaments combined
• Four tendons bind the shoulder
together in order to create a
stable and movable joint
The Shoulder Joint
• The teres minor is a small thin
muscle that connects from the
lower scapula to the humerus
• The infraspinatus is a large flat
muscle that connects from the
scapula to the humerus
• The subscapularis is a large flat
muscle that connects from the
bottom of the scapula to the lower
part of the shoulder
• The superspinatus is a thin muscle
that connects the top of the
scapula to the top of the humerus
The Shoulder Joint
• https://www.youtube.com/watc
h?v=D3GVKjeY1FM
The Knee Joint
• The knee joint is a hinge joint that
connects the femur to the lower
leg
• Since the knee has to support large
amounts of weight from many
different directions the knee is
fairly complex
• The knee contains three different
articulations
• Twi between the femur with the tibia
• One between the femur and patella
The Knee Joint
• The joint has 7 major ligaments
that keep it providing flexion and
extension while limiting rotation
• The patellar ligament connects
the patella to the tibia
• The two popliteal ligaments
surround the patella and
connect the ends of the femur
and the tibia/fibula
The Knee Joint
• Inside the joint capsule the
anterior cruciate ligament (ACL)
and the posterior cruciate
ligament (PCL) attach the femur
to the tibia
• The tibial collateral ligament
and the fibular collateral
ligament run outside the capsule
and connect the femur to their
respective bones
The Knee Joint
• https://www.youtube.com/watc
h?v=Tkb4YzvFSE4