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Synovial Joints

RELATED WORDS

  • diarthroses
  • articular capsule
  • articular cartilage
  • synovial fluid
  • synovial memberane
  • monoaxial joints
  • biaxial joints
  • multiaxial joints
  • ball and socket joints
  • gliding joints
  • hinge joints
  • saddle joint
  • pivot joint
  • condylar joint

Definition of Synovial Joints

Highly mobile joints formed by the articulation of bones enclosed in a capsule containing synovial fluid in the human body
Examples of synovialjoints are joints present in knee, wrists and elbow.

More About Synovial Joints

  • It is also known as “mobile joints” or “diarthrosis joint” with regards to the functional mobility of the joints
  • It is very different from the cartilaginous and the fibrous joints when the structural and functional aspects are considered
  • The main difference lies in the presence of the capsule and synovial fluid around the surface of the articulating bones in synovial joints
  • A typical synovial joint consists of the two articulating bones separated by a narrow cavity known as articular cavity
  • This cavity is filled with a slippery fluid known as synovial fluid produced by the synovial membrane
  • Synovial fluid lubricates the joint and provides protection against the shocks, preventing friction and damage during movement
  • It also provides nourishment and removes the wastes from the articular cartilage
  • A capsule like structure is formed around the articulating bones and it is known as articular capsule
  • The periosteum of the two bones of the joints are externally connected by ligament
  • The inner surface epiphyses of the two bones have hyaline cartilage or articular cartilagethat absorbs shock and reduces friction
  • The inner articular capsule surrounding the synovial cavity is lined by the synovial membrane that contains the synovial fluid
  • The synovial joints are of three types based on the plane of the movement of the bones
  • They are monoaxial joints having one plane of movement. E.g: Hinge joints(Ginglymus joints)
  • Biaxial joints having two planes of movement. E.g: Condyloid joint (Ellipsoidal joint)
  • Multiaxial joints having three or more than three planes of movement. E.g: Ball and socket(Spheroid joints)
  • Basically there are six types of synovial joints as follows:
    • i) Ball and socket joints – joints in the shoulder and the hip bones
      ii) Hinge joints - joint in the elbow, knee joint, interpharyngeal joints
      iii) Gliding joints - joints in the bones of the wrist, intertarsal joints, articular processes between vertebrae
      iv) Pivot joints - atlanto-axial joint in the upper part of neck
      v) Saddle joints - joint present at the base of the thumb
      vi) Condylar joints - mandible to the temporal joint