Nerve distribution of the cervical spine

The cervical spine area is particularly rich in nerves. We know that the incidence of cervical spondylosis is relatively high. When the cervical spine is affected, it is easy to cause compression of the nerves, which will cause more serious symptoms, easily lead to insufficient blood supply to the brain, and easily cause some radiating pain. This is all related to the nerves of the cervical spine. The nerve distribution of the cervical spine is relatively complex. Let us understand the nerve distribution of the cervical spine.

Nerve distribution of the cervical spine

The spinal nerve trunk is very short and immediately divides into four branches after exiting the intervertebral foramen, namely the anterior branch, the posterior branch, the meningeal branch, and the communicating branch.

1. Meningeal branch is also called sinusvertebral nerves. Each meningeal branch receives branches from the adjacent gray communicating branches or from the thoracic sympathetic ganglia, and then returns to the vertebral canal through the intervertebral foramen, dividing into transverse branches, ascending branches and descending branches, which are distributed in the spinal cord capsule, vascular wall, periosteum, ligaments, intervertebral discs, etc. The ascending branches of the upper three pairs of cervical nerve meningeal branches are larger and are also distributed in the dura mater of the posterior cranial fossa.

2. The communicating branch is a thin branch connecting the spinal nerve to the sympathetic trunk. Among them, the one that originates from the spinal nerve and connects to the sympathetic trunk is called the white communicating branch, which is named because it is composed of myelinated fibers. The nerves that originate from the sympathetic branches and connect to the spinal nerves are called gray communicating branches, which are named after the fact that they are composed of unmyelinated fibers.

3. The posterior branch is mixed and thin. It runs backwards between the transverse processes of adjacent vertebrae or through the posterior sacral foramen. Except for the sacral nerve, the posterior branches of the spinal nerves generally go around the outside of the superior articular process and run backwards between the adjacent transverse processes and then divide into medial and lateral branches. They are further divided into muscular branches distributed in the deep muscles of the neck, back, and lumbar sacral region; cutaneous branches are distributed in the skin of the occipital, neck, back, waist, sacrum, and buttocks. Among them, the posterior branch of the first cervical nerve is relatively thick and is called the suboccipital nerve. It passes through the upper part of the posterior arch of the atlas and the lower part of the vertebral artery and is distributed in the occipital muscles. The cutaneous branch of the posterior rami of the second cervical nerve is called the greater occipital nerve, which penetrates the trapezius muscle to the subcutaneous tissue and is distributed in the skin of the occipital region. The medial branch of the posterior rami of the third cervical nerve also passes through the trapezius muscle and is called the third occipital nerve, which is distributed to the skin of the suboccipital area. The posterior branch of the lumbar nerve and its medial and lateral branches pass through the bone fibrous foramen formed by the transverse process, articular process and ligaments, the bone fibrous canal between the mastoid and accessory processes of the lumbar vertebrae, or the fissure of the thoracolumbar fascia during their respective courses. Under normal circumstances, these holes, tubes or fissures have a protective effect on the blood vessels and nerves passing through them. However, if bone hyperplasia or ligament hardening occurs around the holes and tubes, it will cause compression on the posterior branch of the lumbar nerve, which is often an important cause of low back and leg pain and can be treated with compression relief surgery. The lateral branches of the posterior rami of the 1st to 3rd lumbar nerves are relatively large and are distributed in the skin of the upper buttocks. They are called the superior gluteal nerves. The cutaneous branches of the posterior rami of the 1st to 3rd sacral nerves are distributed in the skin of the middle gluteal area and are called the middle gluteal cutaneous nerves.

4. The anterior branch is thick and mixed, distributed in the muscles and skin of the anterolateral trunk and limbs. The anterior branches of the human thoracic nerves maintain their original segmental course and distribution, while the anterior branches of the other spinal nerves are interwoven into plexuses to form four spinal plexuses, namely the cervical plexus and brachial plexus. Lumbar and sacral plexuses. Branches are distributed from each cluster.

The distribution pattern of spinal nerves is as follows:

(l) Larger nerve trunks often run alongside blood vessels, within the same connective tissue sheath, forming a vascular-nerve bundle. Like blood vessels, they mostly run along the flexion side of the joints and are divided into superficial and deep branches.

(2) The branches of larger nerves are generally divided into cutaneous branches, muscular branches, and articular branches. Cutaneous branches pass through the deep fascia from the deep surface to emerge superficially under the skin and may be distributed along with superficial veins. They mainly contain somatic sensory fibers and visceral motor fibers (the latter innervate vascular smooth muscles, arrector pili muscles and sweat glands). Muscle branches mostly originate from the proximal end of the muscle and near the starting point and enter the muscle along with blood vessels. They mainly contain somatic motor and somatic sensory fibers. The articular branches are emitted near the joints. A nerve with a long course often has multiple branches that reach several joints along the way. Similarly, a joint can receive the articular branches of several nerves at the same time, and the articular branches are mainly composed of somatic sensory fibers.

(3) During embryonic development, the blood vessels accompanying some large nerves may degenerate without being noticeable. For example, the sciatic nerve in adults has no accompanying blood vessels.

(4) The distribution area has certain segmental and overlapping characteristics.