ORIGIN: Spinal cord segment C2.
COURSE/DISTRIBUTION: This nerve takes origin from spinal cord segment C2 and leaves the vertebral canal by passing between the atlas and axis bone in the intervertebral foramen between the two.
It merges between the posterior arch of atlas and the lamina of the axis, anterior to the obliquus inferior. It then divides into medial and lateral branches.
Medial branch is called the greater occipital nerve. It runs upwards between the obliquus inferior and semispinalis capitis. It then pierces the latter and supplies it. It supplies the skin of the scalp as far as the vertex.
Runs between the transverse processes of the axis and the alas. It merges between the longus capitis and the levator scapulae. It then divides into its terminal branches – ascending and descending branches.
|Its terminal part
joins C2 ventral ramus to form a nerve trunk that helps to form the following
|Muscular branch to longus capitis and longus colli|
|Inferior root of ansa cervicalis.|
ROOT VALUE: C2.
Electronic School of Medicine
Creator: Oluwole Ogunranti