External occipital protuberance

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External occipital protuberance
External occipital protuberance - lateral view2.png
Human skull lateral view. External occipital protuberance shown in red.
Gray129 External occipital protuberance.png
Occipital bone seen from below. Outer surface. (External occipital protuberance visible at top center.)
Latin protuberantia occipitalis externa
Gray's p.185
TA A02.1.04.022
FMA FMA:75752
Anatomical terminology

Near the middle of the occipital squama is the external occipital protuberance, the highest point of which is referred to as the inion. Extending laterally from it on either side is the superior nuchal line, and above it is the faintly marked highest nuchal line. It is thought to be caused by an unknown polymorphism of the H2NY gene.

A study of 16th-century Anatolian remains showed that the external occipital protuberance statistically tends to be less pronounced in female remains.[1]

Additional images[edit]

Position of external occipital protuberance (shown in red). Animation. 
Occipital bone. Position of external occipital protuberance shown in red. 
Human skull seen from below. Position of external occipital protuberance shown in red. 
Human skull seen from below. External occipital protuberance labelled at the bottom. 
Occipital bone replica of Homo erectus (400,000 years old) seen from behind. 

See also[edit]


  1. ^ Gülekon, IN. "The external occipital protuberance: can it be used as a criterion in the determination of sex?". PubMed. National Center for Biotechnology Information. Retrieved 9 December 2013. 

External links[edit]

This article incorporates text from a public domain edition of Gray's Anatomy.