Editing Atlas (anatomy) (section)

===Lateral masses===
The lateral masses are the most bulky and solid parts of the atlas, in order to support the weight of the head.

Each carries two articular facets, a superior and an inferior.

* The ''superior facets'' are of large size, oval, concave, and approach each other in front, but diverge behind: they are directed upward, medially, and a little backward, each forming a cup for the corresponding [[Condyle (anatomy)|condyle]] of the occipital bone, and are admirably adapted to the nodding movements of the head. Not infrequently they are partially subdivided by indentations which encroach upon their margins.
* The ''inferior articular facets'' are circular in form, flattened or slightly convex and directed downward and medially, articulating with the axis, and permitting the rotatory movements of the head.