Post on 25-Dec-2015
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 from the
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 • 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
• https://www.youtube.com/watch?v=M-FQGMPfGac
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
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 Movements
• 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 Movements
• 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