Anatomy
A midline bump on back of head, on the external surface of satellite-dish-like vertical part (squama) of occipital bone, halfway between the foramen and its highest point.
The highest nuchal lines run laterally from the protuberance, with the superior nuchal lines located slightly below. The median nuchal line runs inferiorly to the foramen, with the inferior nuchal lines radiating laterally from it, halfway along its length. These lines demarcate muscle attachments.
Clinical
Occipital bone forms base and much of back of skull. The large foramen (Magnum) is formed at anterior side of base, through which the spinal cord passes.
Articulates with spine (C1 – atlas) in “yes”/nodding head movement, and via C1 with axis (C2) in “no”/rotation and lateral flexion. Behind and above foramen, large curved, expanded squama. Articulates with parietals, temporals, sphenoid.
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