Cervical Spine Anatomy (Neck)

Unless you wake up with a sore neck and are unable to turn your head (we’ve all been there), you probably don’t give the cervical spine — more commonly known as the neck — much thought.

The uppermost part of the spinal column, the cervical spine is a complex structure of bones, discs, muscles, ligaments, nerves, and tendons. Both strong and delicate, the cervical spine is an incredible structure that carries the weight of your head (10-11 pounds), protects the spinal cord, supplies blood to the brain, and allows a wide range of motion, supporting your head and neck movements, such as nodding, turning your head from side to side and looking up and down.

The cervical column is comprised of seven bones (C1 to C7) uniquely shaped to protect the spinal cord that descends from the base of your skull and the spinal nerves or root that exit the spine between each set of bones.

Cervical Spine Characteristic Features

Vertebrae

The seven vertebrae in the cervical spine range from the base of the skull to the top of the shoulders. The smallest within the entire spinal column, these vertebrae provide support for the head, protect the spinal cord, give the neck structure, and support head and neck movements.

Atlas and Axis

The upper cervical spine is unlike any other part of the vertebral column. The atlas (C1) and axis (C2) are referred to as “atypical vertebrae” because they have features that set them apart from the rest of the cervical spine.

The atlas and axis are part of the spine’s craniovertebral junction (CVJ)—this is where the base of your brain becomes part of your spinal column.

The atlas and axis make up the most mobile section of your entire spine. Working together, these vertebrae are responsible for approximately 50% of flexion (bending forward) and 50% of rotation; the nodding, bending, and rotation movements of the head.

While the C1 and C2 allow for tremendous ranges of neck movements, they also help support your head, too.

C3-C7 Vertebrae

Cervical vertebrae C3-C7 are similar in shape and function and are known as “typical” vertebra. The vertebral bodies are round shapes. If you compare the thoracic (mid-back) and lumbar (low back) vertebrae to the cervical, you’ll see the C3-C7 bones are smaller.

At the back of the vertebral body are bony arches that project outward to form the facet joints and spinous processes. These bony elements naturally create a hollow opening in the center of the cervical spinal column—a canal that houses and protects the spinal cord.

C7 has a longer spinous process than other vertebrae. If you place your hand at the back of your neck, you can feel this bone protruding through the skin.

Intervertebral Discs (IVD)

The cervical spine has 6 intervertebral discs (IVD). They are found between each level starting below C2 (axis). The discs are strong flexible tissues of fibrocartilage made up of two components:

• Annulus fibrosus: the outer portion of the disc, this protective tire-like layer is strong, yet flexible.

• Nucleus pulposus: inner gel-like structure surrounded by the annulus fibrosus.

Each disc functions to hold the upper and lower vertebrae together. They also act as shock absorbers to the demands placed on the spine. While movement at a single disc level is minimal, all of the vertebrae and discs together allow for a significant range of motion in the spine.

The height of the disc creates spaces between vertebra—nerve passageways called foramen or neuroforamen, formed on either side. Spinal nerve roots branch off the spinal cord, in pairs, and leave the spinal column through the foramen. From there, the nerves branch out to different areas of the body to pick up sensations (e.g., hot, cold, pain) and carry the signals to the brain. They also relay brain signals to control movement in the arms, legs, and torso.

Cervical Spine and Supporting Structures

Ligaments, tendons, and muscles are soft but strong tissues that help support the cervical spine as well as the entire spinal column by limiting excessive movement. Joints in the cervical spine also help provide mobility and structural support.

Muscles

Over 20 muscles in the cervical spine extend from the base of the skull down to the collarbone and shoulder blades. These muscles provide support for your head and neck, help the head move in different directions, and assist with breathing, chewing, and swallowing. There are three main groups of neck muscles: anterior, lateral, and posterior, categorized based on their position on the neck.

Anterior Neck Muscles

Anterior neck muscles are found on the front of the neck. They play a role in speech, swallowing, breathing, and head movements. There are multiple anterior neck muscles, including:

• Infrahyoids: A group of four muscles that move your voice box (larynx) up and down.

• Playtsma: Covers part of the shoulder and upper chest, extending to the jaw. Assists with jaw and mouth movements.

• Scalenes: Three muscles that help stabilize cervical vertebrae, move the head, and move your ribs when you are breathing.

• Sternocleidomastoid: One of the largest neck muscles, it begins behind the ear and stretches down to the collarbone. This muscle helps move your head and extend your neck.

• Subclavius: Keeps your collarbone stable when you move your arms and shoulders.

• Suprahyoids: A group of four muscles that move your hyoid bone (just below your jawbone) when you chew, speak, and swallow.

Lateral (Prevertebral) Neck Muscles

The lateral prevertebral muscles are a group of cervical muscles located on either side of the neck. These muscles are responsible for rotating the head and side-to-side head movements. They also help stabilize the cervical vertebral column. They include:

• Longus capitis & longus colli: Two muscles that help twist the head from side to side, and twist and bend the cervical spine.

• Rectus capitis anterior & rectus captitis lateralis: Two muscles that control head movements.

Posterior Neck Muscles

Posterior neck muscles are located at the back of the neck. This group of muscles extends from behind the ear to the top of the shoulder on both sides of your neck. They help stabilize the vertebral column and assist with head movements. They include:

• Splenius capitis and splenius cervicis: Help you flex, extend, rotate, and tilt your neck.

• Suboccipital muscles: Group of four muscles that help extend your head in different directions and play a role in small head movements.

• Transversospinalis muscles: Group of five muscles that help the head tilt from side to side and move forward and backward. They also provide stability for the cervical, thoracic, and lumbar spines.

Ligaments

Ligaments are strong bands of fibrous, rubberlike tissue. In the neck, ligaments help connect the cervical vertebrae together and keep them stable. Tendons are fibrous cords of soft tissue that attach muscles to bone in the neck and throughout the rest of the body. Ligament injuries are called sprains, while tendon injuries are strains.

Joints

The bones in your neck are connected by facet joints — small joints that have cartilage (slippery connective tissue) to support motion between the 7 vertebrae in the cervical spine. Facet joints work with the neck muscles to provide mobility and flexibility in the neck to help you move your head in different directions.

Over time, facet joints can degenerate and develop osteoarthritis (spondylosis) when the slippery cartilage protecting the joint wears away. This can result in the vertebrae rubbing together during movement and at rest.

Cervical Spine and the Central Nervous System

The cervical spinal nerves, sometimes called nerve rootlets, exit the spinal canal through the neuroforamen in pairs—1 nerve exits on the left side and 1 on the right. These nerve structures are sometimes numbered to correlate with the level in the cervical spine: C1 through C8.

Each cervical nerve innervates or provides sensation (feeling) and motor function (movement) to both sides of a corresponding part of the upper body. In general, the cervical spinal nerves perform these functions including:

• C1, C2 and C3 provide motor function to the head and neck, as well as sensation from the top of your scalp to the sides of your face

• C4 enables you to shrug your shoulders and automatically causes the diaphragm to contract when you are breathing. The 4^th cervical spinal nerve also provides sensation to your neck, shoulders and parts of your upper arms

• C5 enables various upper body movements like lifting your shoulders and flexing your biceps, and enables feeling toward the tip of the shoulder

• C6 allows you to move your wrists and flex your biceps and also provides sensation to the inner (thumb) side of your forearms and hand

• C7 powers the triceps muscle on the back of your upper arms and transmits sensation along the back of the arms, and down to the middle finger

• C8 allows you to open and close your hands (hand grip) and gives you the ability to feel the outer (pinkie) side of your hands and forearms

Common Cervical Spine Conditions and Injuries

Common disc disorders include degenerative disc disease and disc herniation that can cause spinal nerve impingement—sometimes called a “pinched nerve.” This can happen when a disc flattens (loss of disc height) or changes shape—the space for a spinal nerve passing through the neuroforamen is restricted. Nerve compression may cause pain that radiates (travels) from the neck into the upper back and arm(s). This condition is called cervical radiculopathy.

Cervical spinal stenosis is a narrowing of the middle portion of the spinal canal and can lead to compression of the spinal cord.

Cervical trauma represents the most serious of the neck conditions a person may experience. Injury anywhere affecting the cervical spinal column can disrupt nerve communication further down the spinal cord, sometimes resulting in paralysis or even death. Damage (even a bruise) to the C4 nerve, which helps power the diaphragm to make breathing possible, can result in losing the ability to breathe unassisted.

Jefferson Fracture of Atlas

A Jefferson fracture is a break in the C1 vertebra (atlas). This fracture often occurs as a result of a diving accident or from hitting the roof of a vehicle in a car accident, for example.

Hangman’s Fracture

A hangman’s fracture, so called because it supposedly happens when someone is hanged, is a bilateral fracture of the C2 vertebra (axis). This fracture can occur as a result of extreme force on the upper vertebrae, often caused by sports or car accidents. Hangman’s fractures are frequently fatal.

Whiplash (Hyperextension)

Cervical whiplash, or hyperextension, is a common injury to the soft tissues (e.g., muscles, tendons, ligaments) surrounding the cervical spine. ​​It is caused by abrupt forward/backward movements of the head and neck. Common causes are car accidents, sports injuries, falls, and other traumas.

Any of these ‘common’ neck disorders can cause compression of the spinal cord resulting in cervical myelopathy. The neck is the most common spinal level to develop myelopathy. Neck pain is a common symptom, although not all patients experience pain.

Ways to Protect Your Cervical Spine

Understanding the anatomy of your cervical spine and the vital nerves it contains should motivate you to adopt behaviors that help prevent neck injury and slow development of degenerative disorders (e.g., cervical disc herniation).

1. Always wear a seat belt. Wearing a seat belt while in a vehicle helps protect against spinal cord injuries in the event of an accident. Without a seat belt, there is a greater risk of injury to the cervical spine, such as whiplash.

2. Protect your head and upper neck by wearing a helmet when biking. Wearing a helmet can help protect your head, brain, and neck from traumatic injury. A recent study found that 78% of adult cyclists who suffered head and neck injuries while cycling were not wearing helmets.

3. Adjust your computer monitor or screen to eye level. When sitting in front of your computer, your eyes should be directed at the top third of your computer screen. If you have to look up or down, adjust your screen/monitor until you can sit comfortably without straining your neck.

4. Don’t tuck your phone between your ear and shoulder. When you’re on the phone, try to avoid cradling your phone between your ear and your shoulder or cradling it in your neck, which requires you to tilt your neck in an uncomfortable way. If you spend a lot of time on the phone, try a hands-free device, such as an earpiece or headset to prevent holding your phone incorrectly.

5. Sleep using a pillow that supports your neck. If you’ve ever waked up with a stiff neck after a good night’s sleep, you know the importance of a good pillow. There are many pillows available that support your cervical spine and keep it in neutral alignment. Look for options that support the natural curve of the neck and help you stay in that position while you sleep.

6. Periodic neck stretching movements and exercises can help release tension and avoid a stiff neck. It’s all too easy to notice a stiff neck at the end of a long workday. Keep your neck muscles flexible and strong by doing occasional stretches throughout the day. Examples include the chin tuck, shoulder shrugs, neck rotation (turning side to side), and neck extension (extending backward and forward).

7. Talk with your doctor about bone health. As we age, it’s important to pay attention to our bone and joint health. Talk to your healthcare provider about nutritional supplements that support healthy bones and joints. Calcium is one of the most important minerals for bone health, and a supplement can help if you’re not getting enough through your diet. Vitamin D helps the body absorb calcium and plays a role in keeping bones healthy and strong.

8. Quit smoking and/or vaping. Lifestyle choices play a role in the health of your cervical spine. Research shows there’s a connection between smoking and degenerative disc disease in the cervical spine. Smoking/vaping can damage blood vessels that spinal discs need for hydration and nourishment, increasing the risk of neck pain and injury. Quitting smoking can help keep your cervical spine healthy and help protect against neck pain.

The cervical spine is an incredibly strong and flexible part of the body. We rely on it to function as it should in order to carry out our day-to-day activities. Since we use it for virtually everything, experiencing neck pain can have a tremendous impact on your quality of life.

If you’re experiencing neck pain or symptoms that indicate a problem with your cervical spine, talk with your healthcare provider. There are a number of injuries and conditions that can affect the cervical spine that develop as a result of injury or natural degeneration over time. Advancements in technology in recent years have made it easier for doctors to diagnose and successfully treat issues related to the cervical spine, helping reduce pain and allowing you to live your life as pain-free as possible.