Obliquus capitis inferior
The obliquus capitis inferior is a fleshy, thick muscle located in the neck. It is the bigger and longer of the two oblique muscles in the neck. This muscle originates from the outer part of the spinous process of the cervical vertebra or the axis. It travels slightly upward and laterally, and inserts into the posterior and lower portion of wing of the atlas. It constitutes the inferior border of the neck's sub-occipital triangle. The muscle performs the key role of providing rotation of the atlas on the axis. It is named similar to other capitis muscles, but it is the only muscle that does not connect with the cranium. The obliquus capitis inferior performs a significant function in proprioception, which is similar to the function of other sub-occipital muscles. A dense presence of Golgi spindles enables it to perform this role. This may be the main function of this muscle along with other sub-occipital muscles, because it facilitates the precise positioning of the head over the neck.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Obliquus capitis inferior