14 Spine Facts Everyone Should Know
14 Spine Facts Everyone Should Know
This content was medically reviewed by our providers on October 4th, 2022.
Your spine is essential for the functioning of your whole body. While much is known about the spine, there are still aspects that remain a mystery to scientists and doctors alike. At the very least, the spine provides a minefield of information about our body that doctors and scientists continue to unearth. Keep reading this article to learn interesting, helpful and unique facts about your spine!
14 Spine Facts Everyone Should Know
Below, you’ll find 14 facts about the spine everyone should know to hopefully enlighten and help you better understand your body and why your spine is important.
Fact 1: The Spine Has Many Working Parts
It’s time for an anatomy lesson. Your spine has many intricate structures. Doctors divide the spine into five categories:
- Cervical: This part of your spine extends from your neck to your mid-back region, containing seven vertebrae.
- Thoracic: The thoracic spine forms the middle of your back and contains 12 vertebrae.
- Lumbar: The lumbar spine extends from the middle of your back to the sacral spine. It forms your lower back and contains five vertebrae.
- Sacral: The sacral spine is located below the lumbar spine and above your tailbone, also known as the coccyx or coccygeal spine. The sacral spine also consists of five vertebrae.
- Coccygeal: The coccygeal, or coccyx, forms your tailbone. It consists of four vertebrae.
In total, there are 33 vertebrae in the human spine. Vertebrae are the small bones that give shape to your spinal column. Your spine also has a complex network of nerves, ligaments, discs, muscles, tendons, cartilage and other tissues.
Here is some information on key structures in your spine:
- Vertebrae: Along your spinal column are stacks of vertebrae, like building blocks. Each vertebra has a piece that projects out from the spine called the spinous process. The bumps you feel when you rub your hand along your spine are from each spinous process. On either side of the spinal column is one pair of vertebrae. There is a hole in the center where each vertebra meets the other. The holes that each pair of vertebrae form creates a tunnel in the middle of the spinal column.
- Neural foramen: The neural foramen refers to the tunnel walls each vertebral segment forms. The spinal cord travels through this neural foramen, also known as the spinal canal.
- Facet joints: ln addition to the spinal canal, vertebral segments also create a bony knob known as facet joints. The facet joints provide flexibility to your spine. They allow movement with each vertebra. As the vertebrae meet to form the facet joint, they are lined with articular cartilage — a spongy material that lets bones glide against each other. Surrounding each facet joint is a watertight sack called a joint capsule made of ligaments and other soft tissues. This capsule is filled with synovial fluid — a substance that lubricates the joint like oil lubricates a car.
- Intervertebral discs: Your discs are fluid-filled, rubbery pads that cushion each vertebral stack in the spinal column. These discs are shaped like pancakes and have a strong, fibrous shell that protects their soft, jelly-like center. They absorb shock between each vertebra to protect your spine from injury.
Fact 2: The Spinal Cord and Spinal Column Are Not the Same
The spinal cord refers to the bundle of nerves that travel through the neural foramen. This bundle of nerves ends about two-thirds down the column. Underneath the spinal cord is another bundle of nerves known as the cauda equina. Cauda equina is Latin for horse’s tail, which is what this bundle of nerves resembles. These nerves provide motor and sensory function to your legs and bladder.
The spinal cord is also protected by various membranes known as the dura mater, arachnoid mater and pia mater. These membranes protect your spinal cord from injury.
In contrast, the spinal column is the stack of vertebrae extending from your cervical spine to your coccyx. The spinal column, also known as the vertebral column, consists of the following tissues:
- Spinal fluid
Fact 3: Your Spinal Cord Forms Part of Your Central Nervous System
Your spinal cord contains spinal nerves that work with your brain to form your central nervous system. It is like a highway nerves travel on, transporting signals to and from your brain. For example, the nerves in your spinal send signals to your legs, telling muscles to contract when you walk. In other words, your spinal cord makes walking possible.
This highway connects your brain with your peripheral nerves — or the nerves scattered throughout your body not located in the spine or brain. Along this highway, there are over 69 million neurons. Comparatively, the brain has around 86 billion neurons.
Fact 4: Our Spine Changes As We Age
When we are born, our spines have 33 vertebrae. However, the vertebrae in our sacral and coccygeal spines fuse as we age. By the time we reach 30, our spine has around 24-26 vertebrae due to the sacrum and coccyx each becoming one bone. This fusion of bones begins around puberty. These bones fuse to provide greater weight-bearing stability to your spine. The sacrum and coccyx, or the pelvic bone and tailbone, are integral to your ability to sit, stand and bear weight.
As we age, several more changes occur in our spine, such as the following:
- Our discs dry out and provide less vertebrae cushioning. They also become more vulnerable to herniation.
- The ligaments and muscles in our spine become less flexible.
- Our spine joints lose fluid and cartilage, contributing to spinal osteoarthritis.
- Our vertebrae lose mineral density and become thinner.
Fact 5: A Healthy Human Spine Is Very Flexible
Your spine is a highly flexible structure. That said, some parts are more flexible than others. The cervical spine is the most flexible section of the spinal cord and column. Elastic ligaments and spinal discs contribute to spinal flexibility, as do your facet joints. Spinal discs prevent friction between each vertebra, and facet joints help you move your spine relatively easily. Without spinal discs or facet joints, you wouldn’t be able to lean or rotate your upper body. Any movement would also be painful.
For this reason, stretching and good posture are essential for maintaining a strong and flexible spine. Your discs and ligaments function best when your spine is in a natural and neutral position. Stretching keeps the spinal ligaments limber, while good posture ensures the discs are in the proper position to function well. Conversely, a stiff back and poor posture increase your risk of disc herniations and other spinal conditions.
Fact 6: Smoking Negatively Impacts Your Spine Health
Various studies show the negative impact smoking has on spine health. One study finds that smoking increases the risk of severe lumbar spinal stenosis, a condition requiring surgery. Smoking also reduces the effectiveness of spinal surgery. For this reason, surgeons often require that patients stop or pause smoking for a certain amount of time before and after surgery.
Fact 7: Human and Giraffe Necks Share Something in Common
At first, you may think human and giraffe necks are opposites — one is short, and the other is long. At the very least, they seem anything but similar. However, human and giraffe necks do share a key characteristic! Both humans and giraffes have seven vertebrae in their cervical spine. That said, the vertebrae in a giraffe’s neck are much larger than those in humans. Humans and giraffes are both members of the mammal family in the animal kingdom. The vast majority of mammals have seven cervical spine vertebrae.
Fact 8: Humans Cannot Live Without a Spine
The spine connects your brain to your body. As the brain animates much of our body, that connection point between the spine, brain and body is essential to your survival. Your body operates on nerve signals. Nerve signals rely on a functioning central nervous system, which consists of your brain and spinal cord. Without these nerve signals, your body would cease to function. As a result, a human can’t live without a spine due to the severed connection between the brain and body it would entail.
Fact 9: Your Spinal Cord Has Memory
As part of your central nervous system, your spinal cord contains rudimentary mechanisms for learning and memory. While these mechanisms are not as fleshed out in your spine as in your brain, they involve your experience and perception of pain. Your spinal cord sends pain signals to injured nerves long after the initial injury. These pain signals protect the injured area until the nerves are healed. In this way, your spine carries a memory of pain.
Additionally, scientists have found cerebrospinal fluid can slow brain aging in mice and improve memory. Cerebrospinal fluid surrounds the brain and vertebrae in your spine. So, the spinal cord carries memory in itself, and spinal fluid supports memory in your brain.
Fact 10: Car Accidents Are the Most Common Cause of Spinal Cord Injuries
According to the World Health Organization (WHO), the leading cause of spinal cord injuries leading to chronic back pain is motor vehicle collisions or other road traffic accidents. Forty-eight percent of all spinal cord injuries stem from motor vehicle collisions or road traffic accidents. There are an estimated 12,000 spinal cord injuries in the United States each year. Thus, nearly 6,000 of those injuries stem from other road traffic accidents.
After motor vehicle collisions and other road traffic accidents, the remaining leading causes of spinal cord injuries in the U.S. are falls, assault, sports injuries and work-related injuries. The percentages for each cause are as follows:
- Falls: 16%
- Assault: 12%
- Sports and work-related injuries: 10%
Fact 11: Male Spines Are Longer Than Female Spines in Humans
The average length of the male spinal column is 71 cm, compared to 61 cm for the female spinal column. Besides this length discrepancy, female spines also have greater curvature, and the point where the brain meets the spine is higher than male spines.
Fact 12: The Top Bone in Your Spine Is Named After a Greek God
The uppermost vertebra in your cervical spine is sometimes called the atlas bone. The reason for this has to do with the Greek god named Atlas. In Greek mythology, Atlas held up the entire world on his shoulders.
Similarly, the uppermost vertebra in your spine holds up your brain — the center of our thoughts, emotions and perceptions. In this analogy, your brain is the world the atlas bone holds up.
Fact 13: You Are Taller in the Morning Than in the Evening
Your spine compresses throughout the day so that you are taller in the morning than in the evening. The reason for this height discrepancy throughout the day is due to the fluid in your spinal discs. The discs absorb fluid when your body is horizontal as you lie down to sleep at night. As you stand and sit throughout the day, the discs expel fluid. The spine compresses as the discs expel fluid, and you get a little bit shorter!
Fact 14: 8 Out of 10 People Experience Low Back Pain
An estimated 80% of Americans have at least one episode of low back pain in their lifetime. These episodes may be acute or chronic. Acute back pain occurs suddenly but does not linger for an extended period. In contrast, chronic back pain is any back pain that lingers for 12 weeks or longer. Acute back pain can progress into chronic back pain. Approximately 20% of individuals who experience acute back pain develop chronic back pain.
Some common back pain conditions include:
- Back sprains and strains: These commonly occur with sports or work-related injuries.
- Cauda equina syndrome: This rare syndrome involves compression on the cauda equina nerve roots and is considered a surgical emergency, as it could cause permanent paralysis.
- Congenital conditions like spina bifida, kyphosis or scoliosis: These conditions are present at birth and involve incomplete or abnormal development of the spine.
- Degenerative disc disease: This condition occurs naturally as we age, involving the drying out and weakening of our spinal discs.
- Herniated or ruptured discs: A herniated or ruptured disc happens when pressure on the disc causes the fluid inside to push through the disc’s fibrous outer shell.
- Sciatica: With this condition, the sciatic nerve becomes pinched, irritated or compressed. The sciatic nerve extends from the cauda equina at the bottom of your spinal cord through your buttocks, hips and down each leg.
- Spinal osteoarthritis: This condition occurs as the cartilage between your spinal joints naturally wears away due to age and general wear and tear.
- Spinal stenosis: With this condition, the neural foramen and other spaces within your spine begin to narrow, causing compressed, irritated or pinched spinal nerves.
Learn More About the Spine and Find Back Pain Relief With Metropolitan Pain & Spine Institute
Whether you’re simply curious about the spine or are seeking back pain relief, we can help at the Metropolitan Pain & Spine Institute! Our spine specialists know all about the spine and how to treat any ailment you suffer with it. For more information or to schedule an appointment with one of our spine specialists, we welcome you to contact us today!