Human Anatomy, Part 2 - K. A. Dubenko, A. K. Kolomiysev, Yu. B. Chaykovsky 2008

Special Part
Peripheral nervous system, systema nervosum periphericum — General Overview
Spinal nerves

As mentioned above, the Spinal Nerves divide into several branches (Fig. 177).

The posterior branches, rami dorsales, of the spinal nerves pass backward between the transverse processes of the vertebrae (the sacral branches pass through the dorsal sacral foramina), dividing into medial and lateral branches, rami medialis et lateralis, which innervate the Skin of the occiput, back, lower back, and buttocks, as well as the intrinsic Muscles of the neck and back.

The posterior branch of the first cervical spinal nerve is called the suboccipital nerve, nervus suboccipitalis. It runs between the Occipital bone and the atlas, innervating the mm. recti capitis posteriores major et minor, semispinalis capitis, and obliquus capitis superior and inferior. It gives off no cutaneous branches.

The posterior branch of the second cervical nerve is called the greater occipital nerve, nervus occipitalis major, and innervates the skin of the occipital region. It gives off no muscular branches.

The remaining posterior Branches of the cervical nerves give off both cutaneous and muscular branches to the skin and muscles of the posterior neck.

The posterior branches of the Thoracic nerves innervate the skin and intrinsic musculature of the back. The cutaneous branches of the upper 4–5 thoracic nerves arise from the medial branches, while those of the lower thoracic nerves arise from the lateral branches.

The lateral branches of the upper three lumbar nerves—the superior clunial nerves, rami clunium superiores—innervate the skin of the upper gluteal region.

The lateral branches of the upper three sacral nerves—the middle clunial nerves, rami clunium medii—innervate the skin of the middle gluteal region.

The anterior branches, rami ventrales, of the spinal nerves innervate the skin and muscles of the anterior neck, trunk, and limbs. The anterior branches retain their metameric arrangement only in the thoracic region, whereas at other levels they form plexuses (cervical, brachial, lumbosacral, and coccygeal) in which nerve fibers are exchanged between different segments.