What Is the Cervical Vertebrae?

The cervical spine refers to the cervical vertebra, which is located below the head and above the thoracic spine. It is located in the cervical section of the spine, a total of 7 pieces, surrounding the cervical spinal cord and its spinal membrane. The intervertebral disc and the ligament are connected to form a forward curved physiological curve. The cervical vertebra is characterized by a small vertebral body with an oval shape. The transverse process has a transverse process hole through which the vertebral artery and vertebral vein pass. The spinous process is short and branched. Be flexible. The upper and lower notches of adjacent vertebrae surround the intervertebral foramen, and spinal nerves and blood vessels pass through.

Chinese name: Cervical spine
Foreign name: cervical vertebra

Meaning: Cervical vertebra
Number of intervertebral discs: 6

Cervical spine I. Overview:

The cervical spine not only supports the weight of the head, but also has a large range of motion. With the increase of age, the lower cervical spine is prone to degenerative changes, mainly manifested by thinning of the intervertebral disc, narrowing of the vertebral space, and making the foramina smaller. At the same time, the vertebra edges are prone to spurs, which compress the roots of the spinal nerve and form cervical spondylosis. When there is a large spur behind the vertebrae, the spinal cord can be compressed, making both lower limbs unstable to walk, and in severe cases, it is difficult to urinate and defecate. If the bone spurs grow on the side of the vertebrae, they can stimulate or compress the vertebral arteries, causing symptoms such as dizziness, headache, and vision loss.

Cervical spine 2. Physiological anatomy:

There are seven cervical vertebrae, of which the 3rd, 4th, 5th, and 6th cervical vertebrae are typical vertebrae, and 1, 2, 7 are atypical vertebrae. Characteristics of a typical cervical spine (3rd, 4th, 5th, and 6th cervical vertebrae):

· The vertebral body is smaller, the left and right diameter is larger than the front and back diameter, the upper part protrudes (forms the side edge joint), and the lower part is depressed;

The foramen are large and triangular;

Vertebral vessels running in the transverse process holes of all cervical vertebrae (typical or atypical) (vertebral arteries and veins, no vertebral artery running in the 7th cervical transverse process hole);

1, 2, 7 cervical spine characteristics. The first cervical vertebra has no vertebral body, and it is called the atlantoid in a ring shape, which is composed of anterior arch, posterior arch and lateral mass. The tooth recess behind the anterior arch forms a joint with the tooth process of the second cervical spine. The oval depression on the side mass forms a joint with the occipital plantar of the skull base, enabling the head to nod. The second cervical vertebra (or pivot) has an upward finger-like protrusion called a tooth process. The atlas can be rotated around the tooth process. The spinous process of the seventh cervical vertebra is particularly long and approximately horizontal, with no branches at the ends, forming nodules, and easily accessible under the skin.

Observe the foramen and transverse process holes. Note that the foramen and transverse process holes are smallest at the 7th cervical spine. Observe the irregular vertebral body of the typical vertebra, the lateral articular process, the triangular foramen and the superior articular surface of the articular process.

Cervical spine III, peripheral muscle groups:

The muscles around the cervical spine can be roughly divided into two parts: the anterior cervical muscle group and the posterior cervical muscle group. The muscles around the cervical spine constitute the cervical spine dynamic balance system.

The anterior cervical muscle group includes: the superior and inferior hyoid muscle groups have little effect on the flexion of the cervical spine. The anterior cervical muscle group mainly plays the role of flexing the cervical spine. The posterior cervical muscle group includes: superficial cervical muscle group: cervical trapezius muscle, head and neck rhomboid muscle; deep cervical muscle group: neck clamp muscle, longest muscle, cervical and sacral rib muscles, cervical spinal muscles. The posterior cervical muscle group mainly plays the role of extending the cervical spine.

1. Superficial cervical muscle group: The platysma and sternocleidomastoid muscles; the platysma and the sternocleidomastoid muscles are located in the superficial fascia, starting from the subcutaneous tissue in the upper part of the chest, the muscle bundles obliquely upward and over the clavicle. At the lower edge of the mandible, most of the muscle bundles are fused to the facial skin muscles, and the anterior muscle is thicker. The superficial neck vein is located on the deep side of the muscle; the cutaneous nerve passes through the muscle to its superficial side. The neck branch of the facial nerve crosses the angle of the mandible and descends to its deep side. When this muscle contracts, it causes the neck skin to show horizontal wrinkles, reducing the depression between the lower jaw and the side of the neck; it helps lower the lower jaw, lower lip, and corner of the mouth.

The sternocleidomastoid muscle is located on the side of the neck and is an important body surface and zone marker. It divides the neck into anterior and posterior triangles. There are two heads at the beginning of the muscle: The sternal head starts from the front of the sternal bone with a round tendon; The clavicle head is flat and muscular, starting from the top of the clavicle to the inside 1/3. The two heads merged and lined up and back, ending at the outer side of the temporal mastoid and the outer half of the superior line.

The superficial side of the muscle has the broad cervical muscle, the external jugular vein, the great auricular nerve, and the cervical cutaneous nerve; This muscle mainly accepts branches from the occipital artery and the superior thyroid artery; the accessory nerves supply the local muscle (motor) when they pass through the deep surface of the muscle; Function: When standing upright, one side of the muscle contracts, causing the neck to flex to the side, and the face to the opposite side and up. Both sides contract at the same time, pulling the head forward; when lying on the back, the muscles on both sides contract, you can raise your head; when the head is fixed, you can raise the thorax to help inhale deeply. Sternocleidomastoid muscle spasm (of unknown cause, sometimes congenital) is one of the causes of crooked neck.

2. Hyoid muscles: sternum hyoid muscle, scapula hyoid muscle, sternum thyroid muscle and thyroid hyoid muscle; they are from the same source as the rectus abdominis and belong to the superficial ventral muscle. The original hypoglossus muscle block is divided into shallow and deep layers. The superficial division is the inner and outer two, namely the upper abdomen of the sternohyoid muscle and the scapula hyoid muscle; the deep layer is divided into two upper and lower segments, attached to the oblique line of thyroid cartilage. muscle.

Four cervical and peripheral nerves

1C1 Cervical spine 1, C1 spinal nerve

Its anterior branch is located in the vertebral sulcus of the posterior arch of the atlas. It travels from the inferior side of the vertebral artery to the outside of the lateral mass of the atlas, and then descends on the anterior side of the atlas transverse process. The posterior sides of the internal jugular veins anastomosis with each other to form the first condyle of the cervical plexus. The posterior branch of the C1 spinal nerve is the inferior occipital nerve, which exits from the upper edge of the posterior arch of the atlas, most of which exits between the vertebral artery and posterior arch, and a few exit from above the vertebral artery. The suboccipital nerve then branches out to the large posterior head rectus muscle, the posterior small rectus muscle, the superior oblique muscle, and the inferior oblique muscle, which dominate these four muscles. The C1 spinal nerve runs between the occipital bone and the posterior arch of the atlas, through the vertebral sulcus, and penetrates the atlantooccipital membrane on the lower side of the vertebral artery.

2C2 Cervical spine 2, C2 spinal nerve

The epidural portion of the nerve root is located between the posterior arch of the atlantoaxial vertebra and the vertebra. It travels inside the arch formed by the atlantoaxial vertebra toward the lateral dorsal side, and then divides into the anterior and posterior branches. The C2 spinal nerve and its branches are closely connected with the posterior membrane of the atlantoaxial axis. The posterior branch is located on the dorsal side of the posterior membrane of the atlantoaxial axis. After communicating with the posterior branch of the C1 spinal nerve, it is divided into a thinner lateral branch and a thicker medial branch. The medial branch is the pillow. Great nerve. At the level of the occipital bulge, the distance of the occipital nerve from the posterior midline is generally 2 to 4 cm; at the level of the posterior arch nodule, it is generally 1 to 1.5 cm laterally; , Generally 2 to 2.5 cm apart. Except for a part of the dominating area, which is distributed in the occipital muscle, the rest is accompanied by the occipital artery distributed on the skin of the occipital region. Some on the deep side of the semispinalis muscle and the surface of the oblique muscle of the head issue small branches that coincide with the suboccipital nerve and the C3 spinal nerve. The anterior branch of the C2 spinal nerve crosses the outside of the atlantoaxial joint capsule, walks horizontally to the plane of the upper articular process of C2, and is fixed on the myofascial fascia of the oblique inferior head. The inferior oblique fascia is also fixed on the posterior atlantoid. The oblique downward movement surrounds the anterior upper part of the medial scalene or scapularis muscle and joins the anterior branch of the C1 spinal nerve through the anastomotic branch to form a common trunk. This neural trunk crosses the dorsal aspect of the medial oblique muscle to the back and turns to the occipital neck behind the sternocleidomastoid muscle. Behind the sternocleidomastoid muscle, it is divided into two rising superficial branches. This superficial branch is combined with the anterior branch of the C3 spinal nerve. The small occipital nerve branches around the sternocleidomastoid muscle and travel to the back of the ear. In the posterolateral part of the mastoid. In addition, a part of the nerves can be directly sent to the posterior midline of the occipital region, and the branch can be directly combined with the ventral branch of the C3 spinal nerve to issue the small occipital nerve. The occipital nerve has the most variation in distribution, with a wide distribution range. There are many anastomosis between the posterior occipital nerve and the branch of the occipital nerve. It is generally believed that the small occipital nerve is distributed on the skin of the occipital region and the back of the ear, and the large auricular nerve is distributed on the skin of the back of the ear and parotid gland.

3C3 Cervical spine 3, C3 spinal nerve

After the spinal nerve bypasses the C3 articular process, it passes through the intertransverse muscle and is divided into the medial branch, lateral branch, and communication branch. The medial branch of the posterior branch of the C3 spinal nerve is the occipital nerve, which is distributed in the skin near the occipital protuberance. The emitted traffic dominates the dorsal and occipital skin above the cleft lip above the occipital protuberance, and communicates with the occipital and occipital nerves. The deep medial branch penetrates the fibrous tissue around the joint and controls the C3 ~ 4 articular process joints.

4C48 Cervical spine 4, C4 8 spinal nerve

The posterior branch of the spinal nerve enters the intertransverse process from the bone fiber hole. After passing through the intertransverse muscle, it is divided into the medial and lateral branches, and the deep branch of the medial branch innervates the cervical interspinous muscle. Between the split muscles, it passes through the origin of the trapezius muscle to become the cutaneous branch, and the medial branch also emits articular branches, which dominate the adjacent articular processes. The lateral branch is shallow in the tendonous tissue at the origin of the head hemispinal muscle, and it innervates the longest neck muscle and the neck clamp muscle.

5 Cervical spine 5, cervical sympathetic nerve

The cervical sympathetic nerve trunk is located behind the carotid sheath, in front of the cervical transverse process, and deep on the anterior fascia. Generally, there are 3 sympathetic nodes on each side, which are called upper, middle and lower necks. The three ganglia are connected to each other by intersegmental branches, and anastomotic branches are connected to the relevant brain nerves. The superior cervical ganglia is located in front of the C4 and C6 or C7 transverse processes, and the posterior side is the cervical long muscle and its fascia. The central cervical ganglion is the smallest at C4. The inferior cervical ganglion is located between the C7 transverse process and the first costal neck and has an irregular shape. Behind the start of the vertebral artery, it is often merged with the T1 spinal ganglia, known as the cervical thoracic ganglion (stellate ganglion). It has many radial branches.

The distribution of postganglionic nerve fibers from the sympathetic ganglia of the neck mainly includes the following branches.

1. It is connected to 8 pairs of cervical nerves via gray communication, and is distributed to the blood vessels, sweat glands, and trichomes of the head and neck with the branches of the cervical nerves.

2. Branches from the ganglia to adjacent arteries, forming internal carotid artery plexus, external carotid artery plexus, subclavian plexus and vertebral plexus, etc. The branches of these arteries are distributed in the smooth muscles and glands of the head and neck and upper limbs, blood vessels , Pupil dilatation and thyroid.

3. The pharyngeal branch from the cervical ganglia directly enters the pharyngeal wall and forms a pharyngeal plexus with the pharyngeal branch of the vagus nerve and glossopharyngeal nerve.

Cervical vertebrae and neck blood vessels:

1 Cervical spine 1, carotid triangle

The upper boundary of the carotid triangle is the posterior abdomen of the biceps, the posterior boundary is the front edge of the sternocleidomastoid muscle, and the anterior boundary is the upper abdomen of the scapula hyoid muscle. This triangle has many internal structures and is located superficially without deep muscle coverage. The main contents are the carotid sheath and its contents, the hypoglossal nerve and its descending branches and accessory nerves. The main structures in the carotid sheath are the common carotid artery, internal jugular vein, and vagus nerve in the rear. In the superficial layer of the arterial sheath, the descending branch of the hypoglossal nerve descends and participates in the formation of the cervix.

The common carotid artery is the main arterial trunk of the neck, which originates from the head and arm trunk on the right and directly from the autonomic arch on the left. There are often variations at the beginning, such as the left common carotid artery and head and arm trunk or the left subclavian artery Together. The common carotid arteries on both sides pass behind the sternoclavicular joint and rise along the trachea and lateral larynx. In the carotid triangle, the common carotid artery is divided into the external carotid artery and the internal carotid artery at the upper edge of the thyroid cartilage.

The common carotid artery has two structures, the carotid sinus and the carotid artery, at the branches of the internal and external carotid arteries. The carotid sinus is an enlarged part at the end of the common carotid artery and at the beginning of the internal carotid artery. There is a baroreceptor in the sinus wall. After stimulation, it can cause a slow reflex heartbeat, vasodilation and lower blood pressure. The carotid bulb is located in the outer sheath of the posterior wall of the internal and external branches of the carotid artery. Its blood supply is mainly from the external carotid artery and is a chemoreceptor that senses the concentration of CO _{2 in the} blood.

2 Cervical spine 2, cervical root

The root of the neck is located deep below the sternocleidomastoid muscle, and important structures of the chest, neck, and upper limbs pass through this area. The anterior scalene can be used as a sign of this area. This muscle starts from the anterior tubercle of the transverse process of the 3rd to 6th cervical vertebrae, the muscle fibers obliquely downward and outward, and stops at the anterior oblique muscle tubercle on the first rib. The space between the anterior and medial oblique muscles is called the oblique space, and the subclavian artery and brachial plexus pass; the anterior oblique muscle has the sacral nerve and the subclavian vein and their branches; the posteromedial pleura and the lungs The cervical segment (left) of the apex and thoracic duct; the lateral subclavian arteries, veins, brachial plexus, and transverse carotid artery are important structures. There are transverse blood vessels and nerves in the chest, neck, and upper limbs on the front, back, and outside of this muscle. When the muscle is spasm, atrophic, fibrotic or has cervical ribs, it can often cause different degrees of compression such as the brachial plexus and subclavian artery, which is called thorax outlet syndrome.

Vertebral artery: through the lateral edge of the long cervical muscle upward, through the transverse process holes of the cervical vertebra above the 6th cervical vertebra, and then into the skull through the occipital foramen, distributed to the brain and inner ear. Chinese statistics show that it usually starts from the first segment of the subclavian artery (96.13%), sometimes it can start from the aortic arch (3.84%), and rarely starts from the common carotid artery. The incidence rate of the accessory vertebral artery was 1.36%, which went up inside the triangle of the vertebral artery; Vertebral vein: Accompanied by the artery of the same name and merged into the craniofabralis vein;