Joints Classification Flashcards
lecture 6
What are the three joint classifications?
Fibrous , Cartilaginous, Synovial
What are fibrous joints
Fibrous joints hold bones together by keeping them steady. They provide stability and protection
What are cartilaginous joints?
Cartilaginous joints are fibrocartilage that holds bones together and allows for a little bit of movement
What are synovial joints?
Synovial joints allow the most amount of movement and different planes of movement depending on which joint it is
Example of fibrous joints
Cranial sutures
Example of cartilaginous joints
Pubic symphysis
Describe synovial joints
They are free moving and are found in most limb joints.
How much movement bones can do and what planes of movement that they can happen in ….
is determined by the joint structure and how they fit together, what the soft tissues are and where they’re located
Why do we need different classes of joints?
To prevent us from falling over and to allow us to walk and move properly, there must be different of joint classes and their functions
What is bony congruence
How much of the bone is going to touch each other (surface area of bones that will touch)
What are the features of the synovial joint
- They have a complex association of tissues and structures
- They have to allow both free movement and controlled movement
What is the difference between the bony congruence of the hip and knee joint
The hip joint has a high bony congruence which makes it more stable while the knee has a low bony congruence which makes it less stable unless there is more soft tissue in it.
Bone ends determine….
the range of motion at a joint
Describe the basic structure of a synovial joint
There are two bone ends with cartilage covering them. The joint capsule wraps around it, The thin layer behind the synovial membrane makes the fluid inside the space which is called the cavity.
Essential things in a synovial joint
- There is hyaline articular cartilage at the end of the bones.
- The joint capsule wraps around the bone to keep things in place
-The space in between the bones is called the joint cavity
-Cavity
What is the synovial membrane
It creates a lot of synovial fluid to fill the cavity
What is the smooth bone underneath the cartilage called?
Subchondral bone
Why does the bone underneath the cartilage have to be smooth
Because it has to move against the neighbouring bone. This ensures a smooth frictionless movement
The joint capsule is made out of
dense fibrous connective tissue which is a sheet that wraps the whole of the joint
Why is the dense fibrous connective tissue present
It won’t tear or rip or let the bones fall away from each other
The lining on the inside of the joint capsule is called….
Synovial membrane
What is the synovial membrane
it is a thin sheet of secretory cells which secrete synovial fluid which is the fluid in the joints
Why should there be synovial fluid in the joints
it is needed in the joint so that there is water or lubrication in the joint when the neighbouring cartilages rub against each other
Synovial fluid is not blood but…
it has the same nutrients as it
What consists of the inner layer of the joint capsule
Little layers of secretory cells making fluid to lubricate the joint
Different parts of the joint capsule will be thicker or thinner..
depending on where we need it and how much movement we need to have
What holds the bones together
Joint capsules
If the joint capsule is tight and thick
Less movement happens on that part of the joint
If the joint capsule is thin and loose
more movement can happen on the part of the joint
What do ligaments connect
Bone to bone
What are the two types of ligaments at synovial joints
Capsular and Collateral ligaments
Medial collateral ligament..
is on the medial side. It connects the femur to the tibia. If your leg tries to abduct, the ligament will stop it from doing so
What are capsular ligaments?
They are part of the joint capsule and are continuous, very articulate located bands that sit in part of the joint capsule. They are present where more support is needed.
What are the two kinds of collateral ligaments
Medial collateral ligament and lateral collateral ligament
Lateral collateral ligament
Runs from the femur to fibula, restricts adduction where it will pull tight to stop it from happening
What are intrascapular ligaments
They are inside the capsule and are separate from it. In some joints, additional bands of dense fibrous connective tissue are located internally to the capsule which hold bones together
What are the two types of cruciate ligaments of the knee
anterior cruciate ligament and posterior cruciate ligament
Describe the anterior cruciate ligament
It starts from the anterior of the tibia, runs backwards of the joint to the posterior of the femur.
Function of the anterior cruciate ligament.
Restricts posterior displacement of femur. If the femur suddenly slides backwards when standing, we will fall over
Describe the posterior cruciate ligament
It starts from the posterior of the tibia, runs through the middle of the joint and attaches anteriorly to the femur
Function of the posterior cruciate ligament
Restricts anterior displacement of femur
Some joints will have pads of cartilage. Why?
To fill in some space and to provide cushioning and shock absorption
What are fibrocartilaginous pads
They are not joints. Instead, they are made out of the same tissue of the joint
What are menisci (plural) or meniscus ( singular) in the knee?
Fibrocartilaginous pads that sit between the femur and the tibia
Shape of the menisci
Half moon or C-shaped
The more stable a joint is..
the less mobile it would be
The more mobile a joint is…
the less stable it is
In synovial joints, there is more mobility..
and there is less stability which is why it is easier to damage the synovial joints by just doing daily activities or sports compared to the fibrous and cartilaginous joints
ROM is dependent on..
-how the bones fit together
-bone end shape
-ligament location and length
-body surface contact
-muscles and the movements they can produce
Explain the body surface contact
If you flex your elbow, the number of degrees of movement you are able to move is dependent on how big your biceps are. Bigger biceps= less rom, smaller biceps = more rom
Uniaxial
One axis
Biaxial
Two axes
Multiaxial
Many axes
Describe the plane joint
Multiaxial
Sliding and Gliding joint
Flat articular surface
Types of synovial joints
Plane
Hinge
Pivot
Condylar
Ellipsoid
Saddle
Ball and Socket
Example of plane joint
Intercarpal and interarsal joint
Describe the hinge joint
Uniaxial
Movements are flexion and extension in the sagittal plane movements
Example of hinge joint
ankle or elbow, interphalangeal joints
Describe the pivot joint
Uniaxial
Movement is rotation
Example of pivot joint
Radioulnar joints, C1-C2 vertebrae
Describe the condylar joint
Biaxial
Flexion and extension
Can rotate when semi flexed
Example of condylar joint
knee and TMJ
Describe the Ellipsoid joint
Biaxial
Can flex and extend
Abduction and adduction
Therefore also circumduction
NO rotation
Example of ellipsoid joint
Wrist joint
Describe the saddle joint
Biaxial
Flexion and extension
Abduction and extension
Therefore also circumduction
Obligatory rotation - opposition
Example of saddle joint
Carpometacarpal joint (base of thumb)
Describe the ball and socket joint
Multiaxial
Flexion and extension
abduction and adduction
Therefore also circumduction
Rotation
Example of ball and socket joint
shoulder and hip
