synchondrosis

synchondrosis /sing′kondrō″sis/ pl. synchondroses [Gk, syn + chondros, cartilage] , a cartilaginous joint creating a union between two immovable bones, such as the synchondroses of the cranium, the pubic symphysis, the sternum, and the manubrium.

Synchondroses (Patton and Thibodeau, 2010)