As shown in the above picture, it is incorrect to rotate the head like this. First, let's take a look at the anatomical map of the cervical spine. As shown in the figure below, each of us has seven (C 1-C7) cervical vertebrae. Today, we will mainly discuss C 1, C2, C3, C6 and C7. We can see that C3 and C6 are similar in shape, but C 1, C2 and C7 are different and play different roles.

The spinal cord is a bundle of slender nerves extending from the brain, which is protected and surrounded by the spine. Compared with the spine, the human head is quite big. It is located above the cervical vertebra, just like a fish tank above the fingers.

It is precisely because of this structure that the center of gravity deviation caused by the circular motion of the head will have a great influence on the cervical spine. This is why there are many muscles and restraining ligaments to protect your head to prevent it from deviating too far.

In daily life, it is safe for us to twist our heads up and down, left and right, but turning our heads in circles is not a natural and unsafe action for the neck. If you often turn your head around in circles, it is undoubtedly out of the body's own protection mechanism and easy to hurt your neck.

Here are three reasons why you shouldn't turn your head and neck around:

1. Because the spinal cord is fragile, you should avoid bumping or hitting. The protective measures of spinal cord are completed by spinal structure, peripheral ligaments, tendons and muscles. In addition, the spinal cord is surrounded by the surrounding spinal bone wall. Generally speaking, the spinal canal has enough space to accommodate bone marrow, but sometimes it becomes narrow (cervical spinal canal stenosis). When this happens, the spinal cord wall tissue will compress and compress the nerves, and the following symptoms are weakness, numbness or pain in the neck or where the nerves pass.

Types of cervical spinal stenosis

Figure 1: Normal spinal canal has enough space to accommodate bone marrow. In general, the distance between spinal canals is 17 ~ 18mm, and it will be reduced to 13 mm or even smaller when the cervical spinal canal is narrowed.

Figure 2: Some people are born with narrower spinal canal than normal people. They may not feel uncomfortable when they are young, but this physiological structure makes them more prone to cervical spinal stenosis, and even a slight neck injury will cause compression on the spinal cord in the cervical spine.

Figure 3: Cervical spinal stenosis is a common symptom in the aging process, which is caused by bone spurs or cervical disc herniation, thickening of ligamentum flavum and cartilage injury. Many people over the age of 50 have this disease and have no symptoms.

So why does the cervical spinal canal narrow? Here are some reasons:

1. Many people are born with narrower spinal canal than normal people, so any slight neck injury will put them at greater risk.

Then the question comes: you never know what happened to someone else's cervical spine. They may not even know themselves (many people with spinal stenosis have no symptoms). Turning around the head can easily put the neck in an extremely fragile position, which will lead to nerve compression and injury for people with spinal stenosis.

Second, the injury of intervertebral plane joint

The spines are stacked on top of each other and move like hinges, and the surface is covered with cartilage to ensure smooth movement. These planar joints allow the neck to bend forward and backward, and prevent excessive bending and sliding between adjacent vertebrae. Due to the mutual restriction of adjacent vertebral bodies, the spine becomes more stable. These joints play an important role in the "normal" range of motion. Because the circular motion of the head is not a "normal" motion, and the vertebrae are easy to rub against each other, it will destroy the plane joints and cause unnecessary structural wear. The rotation of the neck will further damage the degenerated cartilage surface, and the instability of the spine will also cause spinal canal stenosis.

Third, the brain has insufficient blood supply.

There are billions of neurons in the human brain, which is a very active organ and has a continuous demand for nutrition and oxygen. These needs are widely supplied through carotid artery and vertebral artery. In extreme cases, when the blood supply to a certain part of the brain is blocked, a stroke will occur.

When you twist your head further back than when you usually look up, you will put pressure on the vertebral artery, thus reducing the blood flowing into your brain. If the artery is blocked, the situation will get worse, leading to dizziness and even loss of consciousness.

Obviously, it is unsafe to rotate the head with an iron ring, and it may cause various problems. Of course, the possibility of the problem depends on many factors, such as age, potential spinal problems and so on. Turning around and turning your head is a potentially harmful exercise. Compared with this dangerous exercise, there are many better ways to relax your neck.