Synchondrosis sphenooccipitalis
The spheno-occipital synchondrosis (also known as the basiocciput synchondrosis) is the synchondrosis between the basisphenoid and basiocciput bones, which together when joined form the clivus. When fused, the synchondrosis is often called the spheno-occipital suture - this is a misnomer - as anatomically it is not a suture.
Development
Developmental progression of the closure of the spheno-occipital synchondrosis takes place over a relatively wide spectrum of ages such that the closure of it cannot be used as a reliable method for bone age assessment and the ages below must be viewed with a degree of healthy circumspection :
Fusion of the spheno-occipital synchondrosis initiates in girls at 12-13 years, and in boys at 14-15 years and is complete by 17-18 years. Fusion begins superiorly and progresses inferiorly, and also starts at the inner surface of the skull base proceeding towards the ectocranial surface .