Bone · Head

Occipital bone

Os occipitale

The occipital bone forms the back and much of the base of the skull. It is pierced by the foramen magnum, the large opening the spinal cord passes through, and carries the two condyles that sit on the atlas so the head can nod. Its outer surface is a busy attachment plate: the trapezius, the splenius capitis and the small suboccipital muscles all pull on the nuchal lines here, which is why the base of the skull is such a familiar band of tension.