External occipital protuberance

The external occipital protuberance is a noticeable bony bump located on the outer surface of the squamous occipital bone at the back of the skull. It sits in the center, at the top part of the external occipital crest, and you can easily feel it where the neck meets the head. This bump and the crest below it are places where the nuchal ligament attaches. The highest point on the external occipital protuberance is called the inion.

From the external occipital protuberance, two faint bony lines extend outwards, known as the superior nuchal lines. Below these lines, several neck muscles attach, including the medially located semispinalis capitis and the laterally positioned superior oblique muscle.