Joints - Anatomy & Physiology

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BACK TO MUSCULOSKELETAL ANATOMY AND PHYSIOLOGY

Joints comprise broadly two categories:

  • Synarthroses form joints that are relatively rigid
  • Diarthroses form joints that are freely movable

Joint Function:

  • Absorb force of impact, transfer force via cartilage to bone
  • Allow a variable degree of movement

Fibrous Joints

  • Most occur in the skull: known as sutures
    • Key in development: allow extension of individual bones during growth
    • Gradually eliminated as ossification progresses
  • Syndesmoses: facing areas of two bones joined by connective tissue ligaments, very limited movement allowed
    • Eg. Joints of the metacarpus in the horse
  • Gomphosis: attachment of tooth to bone within its socket

Cartilaginous Joints

  • Synchondroses: eg. joints between epiphyses and diaphyses of juvenile long bones, disappear on maturity
    • Permanent synchondroses: the joint between the skull and hyoid
  • Symphysis: articulating bones are divided by a succession of tissues, with cartilage covering the bones or the tissue between
    • Eg. mandibular, pelvic, vertebral

Synovial Joints

  • Articulating joints are separated by a fluid-filled joint cavity, which is bounded by a synovial membrane
  • Often the synovial membrane is reinforced by a fibrous capsule and ligaments restricting joint movement
  • Cartilage covers the articular surfaces

Joint Pathology

For links to joint pathology, go here