A&P - 9.3 Cartilaginous Joints

cartilaginous joint - general characteristics

• articulating surfaces are united by cartilage (tough but flexible type of connective tissue)

• no joint cavity

• can synarthrotic or amphiarthrotic

types of cartilaginous joints

• synchondrosis

• symphysis

synchondrosis

cartilaginous joint where the bones are joined by hyaline cartilage

• rigid bridge of hyaline cartilage unites the bones of a synchondrosis joint

• can be temporary or permanent

temporary synchondrosis

growing layers of cartilage where once bone growth stops the cartilage disappears and is replaced by bone

• due to lack of movement between bone and cartilage it’s functionally classified as a synarthrosis

• example:

  • epiphyseal plate (growth plate) of a growing long bone

    • region of growing hyaline cartilage that unites the diaphysis (shaft) of the bone to the epiphysis (end of the bone)

permanent synchondrosis

retain their hyaline cartilage and thus do not ossify with age

• due to lack of movement between bone and cartilage it’s functionally classified as a synarthrosis

• example:

  • thoracic cage

    • first sternocostal joint - where the first rib is anchored to the manubrium by its costal cartilage (articulations of the remaining costal cartilages to the sternum are all synovial joints)

    • formed where the anterior end of the other 11 ribs is joined to its costal cartilage

symphysis

cartilaginous joint where the bones are joined by fibrocartilage

• articulating bones are separated by a wedge or pad of fibrocartilage

• gap separating bones at a symphysis may be narrow or wide

• functionally classified as an amphiarthrosis

  • fibrocartilage has a much greater ability to resist pulling and bending forces when compared with hyaline cartilage

  • gives it the ability to strongly unite the adjacent bones but can still allow for limited movement to occur

examples of narrow gap between bones

• pubic symphysis

  • pubic portions of the right and left hip bones of the pelvis are joined together by fibrocartilage across a narrow gap

• manubriosternal joint

  • fibrocartilage unites the manubrium and body portions of the sternum

examples of wide gap between bones

• intervertebral symphysis

  • located between the bodies of adjacent vertebrae of the vertebral column

  • thick pad of fibrocartilage called an intervertebral disc strongly unites the adjacent vertebrae and provides cushioning between the vertebrae (important when carrying heavy objects or during high impact activities such as running or jumping)

  • width is important because it allows for small movement between the adjacent vertebrae