Basilar occiput

Basilar occiput (basiocciput) anterior to and forming the anterior border of the foramen magnum. 

The superior petrosal sinuses lie in the attached margin of the tentorium cerebelli along the superior border of the petrous portion of the temporal bone. They drain into the sigmoid sinus, and then to the internal jugular vein. The inferior petrosal sinuses lie at the junction of the posterior border of the petrous portion of the temporal bone with the basilar process of the occiput. They drain into the internal jugular vein. 

Occiput The sphenoid articulates with the basilar portion of the occiput (the spheno-basilar joint), a synchrondrosis that is cartilaginous until age 20 to 25 years, and then converts to cancellous bone. It exhibits flexibility, not articular mobility. 

In flexion, the occiput rotates about a transverse axis directly superior to the foramen magnum at the level of the confluence of sinuses. As It rotates, the basilar part and the condyles move anteriorly and superiorly, directly Influencing the temporal bones, and the squama moves posteriorly and slightly laterally. The greatest lateral deviation occurs at the lateral angles. 

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See also in sourсe #XX -- [ ]

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