Corpus: Rectus posterior major capitis muscle

The rectus posterior major capitis muscle is a skeletal muscle located in the neck and is part of the autochthonous back musculature.

The rectus posterior major capitis muscle originates from the spinous process of the axis (the 2nd cervical vertebra). It runs straight upward (cranially) to attach to the inferior nuchal line of the occipital bone.

The rectus posterior major capitis muscle is innervated by the medial branches of the posterior rami of the spinal nerves from segments C1 and C2. The dorsal ramus of the first spinal nerve is specifically known as the suboccipital nerve.

When the rectus posterior major capitis muscle contracts on one side, it tilts and rotates the head to the same side. When both sides contract simultaneously, it results in dorsiflexion of the head.

In some individuals, the rectus posterior major capitis muscle may be divided into two parts or, in rare cases, may be completely absent.