synchondrosis synchondrosis a synchondrosis (or primary cartilaginous joint) is a type of cartilaginous joint where hyaline cartilage completely joins together two bones. synchondroses are different than symphyses (secondary cartilaginous joints) which are formed of fibrocartilage. synchondroses are immovable joints and are thus referred to as synarthroses.are all synchondroses synarthrotic/immovable synchondrosissagittal section through the clivus of the skull demonstrating the location of the spheno-occipital synchondrosis in an infant.identifiersta98a03.0.00.016ta21529fma7497anatomical terminology 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 apophyses synchondroses in the developing hip bone composed of the ilium, ischium and pubis spheno-occipital synchondrosis