Nerves of the Cervical Spine
The C1 spinal nerve is unique. It does not have a typical dorsal root ganglion. The ganglion cells are located in the rootlets of the spinal accessory nerve.
The dorsal ramus of C1 is found with the posterior suboccipital muscles. In some individuals there is a cutaneous branch.
The ventral ramus of C1 runs past the posterior arch of the atlas (C1), behind the superior articular process. It innervates the atlanto-occipital joint and then enters the cervical plexus.
The C2 spinal nerve is located behind the lateral atlanto-occipital joint.
The dorsal ramus supplies the superficial posterior neck muscles, and becomes the greater occipital nerve running over the occiput.
The ventral ramus innervates the lateral atlantoaxial joint and then joins the cervical plexus.
The spinal nerves of C3-C7 are located in their intervertebral foramina. C8 joins them and is found in the C7-T1 foramen.
The ventral rami of C3 and C4 join the cervical plexus. The lower ventral rami join the brachial plexus.
The dorsal rami of the typical spinal nerves form lateral branches that innervate splenius, longissimus, and iliocostalis. The medial branches innervate the cervical zygapophysial joints, and the deeper and medial posterior neck muscles.
Gray rami communicantes
Gray rami communicates arise from the stellate ganglion and from the ventral rami of the cervical nerves. They form a plexus which is called the vertebral nerve. The vertebral nerves runs with their vertebral arteries in the transverse foramina and into the posterior cranial fossa.
The sinuvertebral nerves of the cervical spine are formed from two roots: the somatic roots from the ventral rami, and teh autonomic roots from the rami communicantes in the vertebral nerve.
The recurrent meningeal branches innervate the dural sac, cervical discs, and posterior longitudinal ligament.
The C1-3 sinuvertebral nerves innervate the ligaments of the median atlantoaxial joint. They then traverse through the foramen magnum and innervate the dura matter overlying the clivus.