A3- joints Flashcards
What are joints?
- where two or more bones meet
- this is known as ‘articulation ‘
- the human body contains approximately 350 joints which are broken into classifications depending on their range of movement and structure
Joints in the upper body …
- thoracic vertebrae joint
- wrist joint
- shoulder joint
- elbow joint
- cervical vertebrae joint
Joint in the lower body …
- sacrum joint
- ankle joint
- hip joint
- knee joint
- coccyx joint
- lumbar joint
What are the classifications of joints?
- fibrous/ immovable joint
- cartilaginous/ slightly movable joints
- synovial/ freely movable joints
Fibrous joints
- these joints do not move
- fixed joints form when the bones interlock and overlap during early childhood
- these are held together by bands of tough, fibrous tissue and are very strong
- cranium = more than 1 bone, numerous bones fused together
Cartilaginous joints
- these allow slight movement
- the ends of the bone are covered in a smooth, shiny covering known as ‘articular’ or ‘hyaline’ cartilage (this is to reduce friction)
- the bones are separated by pads of fibre-cartilage which are able to absorb immense force
- vertebrae are able to move as these pads compress
Synovial joints
- these have a very high level of mobility and are vital to all sporting movements (most joints in the body are synovial)
- a synovial joint has 2 bones, the ends of which are covered in articular cartilage which allows the movement with friction
- they will always have a synovial cavity (space between the bones) and surrounded by a capsule (filled with synovial fluid) , a little bit like a bubble
- synovial fluids lubricates and nourishes the joint
- the joint capsule is held together by strong ligaments
- these ligaments avoid dislocations while being flexible enough to allow a wide range of movement
Joint capsule
- an outer sleeve to help hold the bones in place and protect the joint
- this capsule will also contain the main structure of the joint
Bursa/ synovial cavity
- a small fluid filled sac which provides a cushion between the tendons and the bones, preventing friction (filled with synovial fluid)
Articular cartilage
- on the ends of the bones that provide a smooth and slippery covering to stop bones rubbing/grinding together
Synovial membrane
- the capsule lining that releases synovial fluid
Synovial fluid
- a thick liquid that lubricates the joint and reduces friction between the bones
- synovial fluid also provides nutrients to articular cartilage
Ligaments
- hold the bones together and keep them in place
Hinge (synovial joint)
- allow movement in one direction only (like a hinge on a door)
- elbow and knee are typical examples
- exercise examples = running or a bicep curl
What are the six types of synovial joint?
hinge, ball and socket, condyloid, gliding, pivot and saddle
Ball and socket (synovial fluid)
- round end of the bone fits into the cup shaped socket in the other bone, allowing movement in all directions
- hip and shoulder
- exercise example = throwing a ball
Condyloid (synovial joint)
- also known as ‘ellipsoidal’ joints
- similar to ball and socket in which a ‘bump’ (condyle) on one bone sits in the hollow formed by another
- movement is backwards and forwards, and side to side (ligaments prevent rotation)
-wrist - exercise example = dribbling or bouncing a ball in basketball, movement comes from the wrist
Gliding (synovial fluid)
- this joint allows movement over a flat surface in all directions
- however this movement is restricted by ligaments
- carpals/ tarsals
- exercise example = jump in netball (pointing toes)
Pivot (synovial joint)
- a circular bones fits over a peg of another bone (allowing controlled rotational movement)
- atlas, axis (neck)
- exercise example = turning your head in any sport
Saddle (synovial joint)
- similar to a condyloid joint (but the surfaces are concave and convex)
- the joint is shaped like a saddle, with the other bone resting on it like a rider on a horse
- movement occurs backwards and forwards, and from side to side
- base of the thumb
- exercise example = gripping a racket in tennis
What are the six types of major joints?
- hip
- elbow
- ankle
- wrist
- shoulder
- knee
What are the soft tissues?
- tendons
- ligaments
- skin
- muscle
- fat
Flexibility …
- the range of movement around a joint or a group of joints
What does flexibility depend on?
- factors including age
- due to the tension of the supporting tissues (tendons) and the muscles that surround the joint, as well as the soft tissues around the joint
Flexion …
- reducing the angle between the bones of a limb at a joint
- muscles contract, moving the joint into a bent position
Example of flexion …
- bending your arm at the elbow
- bicep contracts pulling ulna and radius, reducing the angle at the elbow
- kicking a football, throwing a tennis ball
Extension …
- straightening a limb to increase the angle at a joint
Example of extension …
- straightening the arm at the elbow
- straightening the elbow
Dorsiflexion …
- an upwards movement, as in moving the foot to pull the toe towards the knee
- ‘hold the door with dorsi’
Plantar flexion …
- a movement that points the toes downwards by straightening the ankle
- ‘point the plantar’
Lateral flexion …
- the movement of bending sideways
- for example at the waist
Horizontal flexion and extension …
- reducing the angle at a joint
Example of horizontal flexion and extension …
- the shoulder joint moving horizontally across the body
Hyper-extension …
- involves movement beyond the normal anatomical position in a direction opposite to flexion
Example of hyper-extension …
- extending a joint past it’s normal range of movement
- cricketer arching back when approaching stumps to bowl or gymnast doing a walkover
Abduction …
- movement away from the vertical mid line of the body
Adduction …
- movement towards the vertical mid line of the body
Where are adduction and abduction commonly seen?
- hip and shoulder
Horizontal abduction and adduction …
- movement of bringing your arm across the mid line of the body in a horizontal plane
Circumduction …
- circular movement that results in a conical action (making circles)
Rotation …
- circular movement of a limb (not circumduction)
Example of rotation …
- turning the head