1. The cartilage bones make their appearance at late stages and after the ossification centers of membrane bones have taken place. The basioccipital was a first bone to occur and is followed by the exoccipital. Also the basisphenoid appears first then the basiparasphenoid. The rest of ossification centers are followed by the supraoccipital, mesethmoid, epiotic, ectethmoid, parasphenoid and pleurosphenoid.
2. The basioccipital occupies the medial part of the basal plate beside the occipital condyle.
3. The ossification center for the exoccipital is the ventral portion of the occipital arches.
4. There are two centers of ossification for the auditory capsule. The first center is the prootic and occupies the cochlear part of the auditory capsule and the second center is the epiotic which replaced the posterior part of the promenintia semicircularis anterior.
5. The nasal capsule has two centers of ossification; the mesethmoid and the ectehmoid respectively.
6. The floor of cranium ossifies through the basisphenoid and parasphenoid bones. The sphenoid complex has nine centers of ossification; single center of rostrum of parasphenoid, two in basisphenoid then paired centers in each of basiparasphenoid, sellaparasphenoid, and alaparasphenoid.
7. The stapes is the only part to ossify in the columella auris.
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