Download - JOINTS
JOINTS
Learning Objectives• To know the different
joint types• To understand how to
classify joint types• To be able to discuss the
importance of the structure and function of a synovial joint
Joints The human skeleton is jointed to
allow movement.
Muscular contraction causes the bones to move about the joints.
A joint is where two or more bones meet and
muscles act together to cause movement.
There are 3 main types of joint found in the body.
Types of Joints
1. Fibrous/ immovable joints The bones at an immoveable joint cannot move -
they overlap or interlock, and are held together by a tough fibre, e.g. the skull.
2. Cartilaginous/slightly moveable jointsThe bones at a slightly moveable joint can only move a little - they are held together by strong straps called ligaments and are joined by protective pads known as cartilage, e.g. the ribs.
3. Synovial joint/freely moveableAt a freely moveable joint the bones move freely.They are also known as synovial joints, andare the largest group of joints found in the body, e.g. the hips, shoulders and knees.
Freely Moveable joints are also known as Synovial Joints.
They are freely moving and occur where 2 or more bones meet.
There are about 70 freely moveable joints in the human skeleton.
These interest us the most because they allow the greatest range of movement and are found in the appendicualr skeleton
Freely Moveable Joints
Cartilage1. Hyaline or Articular cartilage- found on the surface of bone
2. Yellow Elastic cartilage- elastic and found in the external ear
3. White Fibrocartilage- tough, dense tissue that acts as a shock absorber. Found between the vertebrae
1. Articular/hyaline Cartilage – A material which covers the end of each bone, and which helps prevent friction between the joint.
• Absorbs compression placed on the joint, protects the joint.
2. Joint Capsule – The outer layer is a tough fibrous layer called the fibrous capsule.
• Increases stability• The inner layer is called the synovial
membrane• Secretes synovial fluid, strengthens the joint
3. Synovial Membrane– Thin membrane which lines the inside of the joint capsule.
• It produces synovial fluid
4. Synovial Fluid – The fluid which surrounds the joint and is contained in the joint cavity.
• Reduce friction between the cartilage• Nourish the cartilage• Get rid of any waste debris
5. Tendons– Strong connective tissue that attached muscle to bone.
• Connect muscle to muscle
6. Bursa- pad of fat provide cushioning between the fibrous capsule and a bone or muscle.
• Cushion the joint and act as shock absorbers
4. Ligaments – A band of strong fibrous tissue, helps prevent dislocation.
• Connect bone to bone
The Synovial Joint of the KneeThe knee is a hinge joint.
Cruciate Ligaments
TendonsTibia/Fibula
FemurArticular(hyaline)Cartilage
Synovial Fluid
Synovial Membrane
Patella
Joint cavity
Joint capsule
The Hip is a ball and socket joint.
Ligaments
Synovial Fluid
Tendons
SynovialMembrane
Pelvis
Cartilage
Femur
The Synovial Joint of the Hip
TASK
1.Label the diagram of a synovial joint using a colour code system
YOU MAY BE ASKED TO LABEL A SYNOVIAL JOINT IN EXAM OR EXPLAIN THE STRUCTURE AND FUCTION
2. List two features that increase joint stability and give their specific function?
Examples of Synovial Joints
Types of Synovial Joints
KEYBall & Socket JointHinge Joint
Pivot Joint
Gliding Joint
Saddle Joint
Condyloid Joint
Synovial joints are classifed according to the shape of the articulating surface.
KEY TERM
ARTICULATION-The different bones that form to make the joint
EXAMPLE
Joint Joint type Articulating bones MovementElbow Hinge joint Humerus, radius, ulna
Write down another example
1. Ball and Socket Joints
The ball has a head shaped of one bone which articulates with a cuplike socket.Allows the greatest range of movement
Examples
HIP
SHOULDER
2. Hinge JointsThey are cylindrical shaped of 1 bone articulates with a depression of an adjacent boneMovement is restricted to bending and straightening
EXAMPLES
ELBOW
KNEE
3. Pivot Joints
These are rounded, pointed or concave of one bone which articulates which a ring shaped bone.
Movement is restricted to 1 bone rotating around the longitudinal axis.
EXAMPLE
VERTEBRAE OFTHE NECK
4. Gliding Joints
The articulating surfaces are flat.
It allows limited movement
EXAMPLES
HAND BETWEEN THE CARPELS
5. Saddle Joints
The articulating surfaces are shaped like a saddle
It allows very limited movement
EXAMPLE
THUMB JOINT
6. Condyloid Joints
The surfaces are flatter and oval forming a shallow joint
It allows the second greatest range of movement.
EXAMPLE
WRIST JOINT
Structure and function
Hyaline/Articular cartilageStructure: Smooth, spongy cartilage that covers end of bone.Function: prevent friction between bones absorb compression placed on the joint protect bone from getting crushed
Joint capsule:Structure: Outer layer is a tough fibrous layer- fibrous membrane.
The inner layer- synovial membrane
Function:strengthen the joint secrete synovial fluid
Synovial FluidStructure; slippery fluid, contained in the joint cavityFunction; reduce friction between cartilage nourish the articular cartilage get rid of waste debris in joint
LigamentStructure; band of strong fibrous tissueFunction; connect bone to bone
Meniscus (cartilage)
Structure: white fibrocartilageFunction: improves the fit between bone ends increases joint stability reduces wear and tear at joint
BursaStructure:fluid filled sacs
Function: prevent friction where bones, ligaments and muscles may rub together
PLENARYIdentify the bones that articulate at the shoulder joint? (2 marks)
Identify the bones that articulate at the elbow joint? (3 marks)
Ball and Socket JointsThe ball has a head shaped
of one bone which articulates with a cuplike socket.Allows the greatest range of movement
Examples
HIP
SHOULDER
Hinge JointsThey are cylindrical shaped of 1 bone articulates with a depression of an adjacent boneMovement is restricted to bending and straightening
EXAMPLES
ELBOW
KNEE
Pivot JointsThese are rounded, pointed or concave of one bone which articulates which a ring shaped bone.Movement is restricted to 1 bone rotating around the longitudinal axis.
VERTEBRAE OFTHE NECK
Gliding Joints
The articulating surfaces are flat.
It allows limited movement
HAND BETWEEN THE CARPELS
Saddle JointsThe articulating surfaces are shaped like a saddle
It allows very limited movement
EXAMPLE
THUMB JOINT
Condyloid JointsThe surfaces are flatter and oval forming a shallow joint
It allows the second greatest range of movement.
EXAMPLE
WRIST JOINT