lesson 2 joints
TRANSCRIPT
Exercise and FitnessLvl 2Lesson 2 – Joints in Action
Lesson 1 Re-cap Progress Test• Complete Work sheet 3 on your own
Classification of Bones• There are 206 bones in the body, these can
be classified as:• Long• Short• Flat• Irregular• Sesamoid
Long Bone• Such as Femur, tibia, fibula, radius ulna,
humerous, • Blood Production occurs in the red bone
marrow of long bones• Long bones provide the body with leverage
e.g throwing a cricket ball.
Short bones• Short bones are found in the wrist and
ankle.• Short bones are useful for delicate
movement where precision is paramount e.g. writing or a surgical operations.
• Small bones also help dissipate large compressive forces generated during walking and running.
Flat Bones• Flat can be found in the scapulae, rib cage,
sternum and cranium• Flat bones offer protection and muscle
attachment e.g. the rib cage protects the heart and lungs
Irregular Bones• Irregular bones can be found in the
vertebral column• Irregular bones provide muscle attachment
points and allow varying movement patterns to occur e.g. The vertebral column
Sesamoid Bones• Sesamoid bones are small bones formed in
tendons e.g. patella ( knee cap).• Sesamoid bones provide protection for
delicate areas.
Joints – 3 types• Fused – Immovable e.g. skull
• Cartiliginous – Slightly movable e.g. between vertebral column
• Synovial – Freely movable e.g hip & knee
Key Joint Facts • Formed wherever two or more bones meet• The skeleton would be ‘fixed’ without them• Bones that form a joint ‘fit well’, if irregularities
exist they are evened out by extra layers of cartilage
• The above are called ‘menisci’ if they only partly divide a joint cavity
• If they fully divide the joint cavity this cartilage is called a disc
• Most joints are held together by ligaments
Ligaments
Fixed or Fibrous Joints• Has no movement• Tough fibrous tissue lies between the
ends of the bones• The ends are ‘dovetailed’ together• There is no joint cavity (space between
the bones’• E.g. sutures in the skull
Example of fixed Joint - Skull
Cartilagenous Joints• Allows some slight movement• Ends of the bones are covered in articular
cartilage• Ends are separated by pads of white fibro
cartilage• Compression of these pads permits slight
movement• These pads also act as ‘shock absorbers’• Eg: intervertebral discs of the spinal column
Synovial Joints• Distinguishing features;
– Ends are covered in articular cartilage– Inners surface of joint capsules is lined with a thin
synovial membrane that produces synovial fluid– Freely movable joints– Characterised by the presence of a joint capsule and
cavity (space between bones)• Range of movement can vary due to the shape of
the bony surfaces forming the joint• The synovial fluid acts as a lubricant for the joint,
provides nutrients • E.G. knee
Synovial Joint Structure
Key Synovial Joints• Ball & Socket
– Shoulder, Hip• Pivot
– Neck• Condyloid
– Wrist
• Saddle– Thumb
• Hinge– Elbow
• Gliding– Carpels
Ball & Socket • Movement in all directions
– Rotation– Adduction / abduction– Flexion / extension
• Articulating bones; Head of femur / pelvis, humerous & scapula
• E.g. – Hips & shoulders
• Sporting eg;– Clearing a hurdle / overhead
clear in badminton
Pivot & Gliding • Pivot
– Rotation– Articulating bones;
• C1 & C2 vertebrae • Neck (C1 vertebrae)
– Turning head to view situations
• Gliding– Movements across flat
surfaces of bones– Articulating bones;
• Clavicle / intercarpal/ intertarsal
– Bending back, landing; feet absorbing impact- flexion / extension of foot
Condyloid• Sometimes referred to
as Ellipsoid• Reduced ball & socket
configuration• Articulating bones;
Radio carpal joint (radius / ulna / carpals)
• Wrist• Flicking of the racket
in badmington
Saddle & Hinge• Saddle
– All movements but no rotation
– Articulating bones• Carpal & metacarpals
– Base of thumb– Gripping of sporting
equipment• Hinge
– Flexion / extension– Articulating bones;
• Humerus / radius & ulna– Elbow– Hitting a backhand
Location of Synovial Joints
Ligaments
Conclusion• Ligaments Connects bone to bone, are strong, inelastic, dense,
fibrous tissue that links boney segments. Prevent any unwanted movement & restricts movement in certain directions
• Joints are formed wherever two or more bones meet, the skeleton would be ‘fixed’ without them. Most joints are held together by ligaments
• Joints can be classified in 2 ways; Functional & Structural • The amount of movement available at the joint determines their
classification • Fixed or fibrous
– Immovable• Cartilagenous
– Slightly moveable• Synovial
– Freely movable
• The main synovial joints are; ball & socket, hinge, saddle, pivot, condyloid, gliding
Now complete….• Now complete worksheet 4