rectus capitis posterior major
noun
rectus cap·i·tis posterior major
| \ -ˈkap-ə-təs-
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Medical Definition of rectus capitis posterior major
: a muscle on each side of the back of the neck that arises from the spinous process of the axis, inserts into the lateral aspect of the inferior nuchal line and the adjacent inferior area of the occipital bone, and acts to extend and rotate the head