Joints Flashcards
Joint
A joint is a connection between two or bones
The three types of joints
Joints are classified based on what type of tissue lies in between the bones:
Fibrous, Cartilaginous or Synovial
Fibrous joint definition and example
Two bones united by a fibrous tissue, with no joint cavity.
The amount of movement depends on the length of the fibrous fibres.
E.G. Interosseous membrane between the radius and the ulna.
Cartilaginous joint
The bones are united by cartilage, with no joint cavity.
Primary = solely hyaline cartilage e.g ribs to sternum
Secondary = Hyaline - Fibrocartilage - hyaline e.g vertebrae bodies
Plane joint (synovial)
The articulations surfaces are flat are can only slide in that one plane
Joint capsules are tight
Hinge joint (synovial)
Permits flexion and extension only
Saddle joints (synovial)
Articulations surfaces are convex and concave
Two axes of movement
Permits flexion, extension, abduction, addiction and circumduction
E.g. joint of thumb
Condyloid joints (synovial)
Permits movement in two axes, but one is usually restricted
Permits flexion, extension, abduction, adduction, circumduction
Ball and socket (synovial)
Spherical and concave articulations surfaces
Multiples axes of movement
Permits all types of movement
Pivot Joints (synovial)
Rotation around a central axis
E.g. Atlanto-axial joint of the cervical spine
Articular surface
Joint surface
How is the knee protected?
2 fibrocartilage discs the medial and lateral menisci = shock absorbers
The articulating surfaces are also covered with hyaline cartilage = smooth movement
What ligaments hold the knee together?
Either side has the lateral and medial collateral ligaments (bands of fibrous connective tissue). They stabilise the femur and tibia in the coronal plane.
The anterior and prosperity cruciate ligament. They prevents excessive forward movements of the tibia in relation to the femur and the opposite.
Why des the humerus head dislocate more easily than the hip?
Shallow ball and socket
No strong ligaments only surrounded by muscle
Synovial joint description
The bones in a synovial joint are joined by a joint capsule, made of an outer fibrous layer and an inner synovial membrane. The joint cavity contains synovial fluid and both ends are covered by articular cartilage.
