A synchondrosis (or primary cartilaginous joint) is a type of
cartilaginous joint
Cartilaginous joints are connected entirely by cartilage (fibrocartilage or hyaline). Cartilaginous joints allow more movement between bones than a fibrous joint but less than the highly mobile synovial joint. Cartilaginous joints also forms th ...
where
hyaline cartilage
Hyaline cartilage is the glass-like (hyaline) and translucent cartilage found on many joint surfaces. It is also most commonly found in the ribs, nose, larynx, and trachea. Hyaline cartilage is pearl-gray in color, with a firm consistency and has ...
completely joins together two bones.
Synchondroses are different than
symphyses (secondary cartilaginous joints) which are formed of
fibrocartilage
Fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its inflexibility and toughness to the former of these constituents, and its elasticity to the latter. It is the only type of ...
. Synchondroses are immovable joints and are thus referred to as
synarthroses.
Examples in the human body
Permanent synchondroses
* first
sternocostal joint (where first rib meets the manubrium of the sternum)
*petro-occipital synchondrosis
Temporary synchondroses (fuse during development)
*
epiphyseal plates
The epiphyseal plate (or epiphysial plate, physis, or growth plate) is a hyaline cartilage plate in the metaphysis at each end of a long bone. It is the part of a long bone where new bone growth takes place; that is, the whole bone is alive, with ...
* apophyses
* synchondroses in the developing
hip bone
The hip bone (os coxae, innominate bone, pelvic bone or coxal bone) is a large flat bone, constricted in the center and expanded above and below. In some vertebrates (including humans before puberty) it is composed of three parts: the Ilium (bone), ...
composed of the
ilium,
and
pubis
* spheno-occipital synchondrosis
References
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Joints