Download Joints in the skeleton

Level 2
Anatomy & Physiology
Southend Personal Trainer Academy
Classification of joints (page 14)
There are three types of joints, they are classified due to their degree of
movement.
1.
2.
3.
Fibrous joints – immoveable with interlocking bones
Cartilaginous joints – slightly movable connected by cartilage
Synovial joints – freely movable they are the most common joint in the body
Structure of synovial joints (page 14)
All synovial joints share some common characteristics;
u Hyaline cartilage covers the ends of bones, this reduces friction. Cartilage is
nourished by synovial fluid
u A joint capsule surrounds the joint and aids stabilisation
u Ligaments connect bones together and provide stability and alignment
u Synovial membrane surrounds the joint capsule and secretes synovial fluid
which acts as a lubricant within the joint
u Muscles cross the joints and connect to bones via tendons, this allows
movements to occur
Structure of synovial joints (page 14)
Cartilage (page 15)
Cartilage is a tough fibrous tissue that helps to prevent compression and friction
within a joint.
u Hyaline cartlilage covers the ends of bones
u Fibrocartilage acts like a shock absorber
Cartilage is dependant on regular activity to feed it via synovial fluid and can be
worn away through overuse, aging and high impact activity
Ligaments (page 15)
u
Ligaments are non elastic and fibrous tissues that can withstand very high
levels of tension
u
However long term prolonged tensions can cause them to stretch irreversably
u
Ligaments have four main functions;
1.
Connecting bones within joints
2.
Stabilising joints
3.
Act as a guide for joint motion and alignment
4.
Helping to prevent unwanted motion
Tendons (page 15)
u
Tendons attach muscle to bone across joints
u
They help to relay the force produced by the muscle
u
For example the achilles tendon which helps to attach the gastrocnemius
muscle in the calf to the heel bone
Types of synovial joints (page 16)
u
There are six sub groups of synovial (freely movable) joints;
1.
Gliding
2.
Pivot
3.
Saddle
4.
Ball and socket
5.
Ellipsoid
6.
Hinge
Gliding joints (page 16)
u
Gliding joints allow to bones to slide past each other
u
Examples include the acromio-clavicular joints, mid carpal and mid tarsal
u
Actions available include elevation and depression of the shoulder girdle
Pivot joints (page 16)
u
Pivot joints allow to bones to rotate around an axis
u
Examples include the axis and atlas joint, radius and ulna
u
Action available is rotation
Saddle joints (page 16)
u
Saddle joints allow movements back and forth and side to side
u
Examples include the carpometacarpal joint
u
Actions available include adduction, abduction, flexion and extension
Ball and socket joints (page 16)
u
Ball and socket joints allow for movements in almost any direction
u
Examples include the hip and shoulder joints
u
Actions available include flexion, extension, rotation, circumduction,
adduction and abduction
Ellipsoid joints (page 16)
u
Ellipsoid joints allows similar movement to a ball and socket joint but to a
lesser degree
u
Examples include the metacarpo-phalangeal joints (knuckles)
u
Actions available include flexion, extension, adduction, abduction and
circumduction but no rotation
Hinge joints (page 16)
u
Hinge joints allow flexion and extension of a limb or appendage
u
Examples include the knee and elbow joint
u
Actions available include flexion and extension
Synovial joints and their range of motion
task (page 16)
u
Using the table on page 16, in pairs discuss which joints have the best and
worst ranges of motion
Joint movement potential and joint
actions (page 17)
u
Flexion – angle of the joint decreasing
u
Extension – angle of the increasing
u
Rotation – a bone rotating along its own long axis
u
Abduction – moving away from the midline of the body
u
Adduction – moving towards the midline of the body
u
Horizontal flexion – arm move towards the midline of the body horizontally
u
Horizontal extension – arm moves away from the midline of the body
horizontally
u
Lateral flexion – bending to the side
u
Circumduction – A cone shaped movement that occurs at ball and socket
joints
Joint movement potential and joint
actions (page 17)
u
Elevation – upwards movement of the shoulder girdle (shrug action)
u
Depression – downward movement of the shoulder girdle
u
Protraction – forward movement of the shoulder girdle
u
Retraction – backward movement of the shoulder girdle
u
Pronation – palm of the hand facing downward
u
Supination – palm of the hand facing upward
u
Dorsiflexion – foot moves toward the shin
u
Plantarflexion – foot moves away from the shin (tip toe action)
u
Inversion – sole of the foot faces inwards
u
Eversion – sole of the foot faces outwards
Effects of exercise on the joints (page
20)
Short term
u
Synovial fluid is released into the joint as we warm up, this provides
lubrication and reduced damage risk
Long term
u
Stronger ligaments
u
Stronger tendons
u
Healthier cartilage
u
Improved mobility