The Vertebral Column

Blaine MitchelAll, Spinal AnatomyLeave a Comment

Bones are good at what they do, complex bundles of tissue, minerals, and water. Their jobs venture well outside of basic skeletal framework. They are protective shields for vital organs including the heart, the brain, and the spinal cord; they are platforms which muscles attach to; and they are manufacturing centres for blood cells. Amazing! Connected through ligaments and moved by muscles, bones hold a huge amount of weight without being crushed or broken.

Your thigh bone is four times stronger than concrete. The minerals calcium and phosphorus make bones (and teeth) strong and solid. Consuming foods which hold these minerals, including yogurt and spinach, will keep your bones healthy. Bones are living, breathing organs. They don’t directly inhale and exhale, but bones do produce red (and white) blood cells. Red blood cells transport oxygen around the body, whereas the white ones act like soldiers and combat germs and disease inside the body. If bones weren’t alive, a broken bone would stay broken indefinitely. Instead, they heal themselves (sometimes with a little help from our medical friends). This biological ability to self-repair is the same for a broken finger as it is for a fractured spine.

At birth, we have around 350 bones in our bodies. As we grow older some of these bones fuse, such as the vertebrae in the bottom region of the spine, called the sacrum and tailbone. If you were a monkey, your vertebral ends would form a tail and assist your balance as you swing through the trees. It requires around 20 years for bones to fully mature into an adult skeleton, which on average contains 206 skeletal bones.

The human skeleton is comprised of bones in many different shapes and sizes, each intended for a particular function. The bones of the spine, referred to as vertebrae, are like cylindrical building blocks. They assemble on top of each other similar to the bricks of a house, separated by little cushions known as discs. The spinal column (also referred to as the vertebral column) is bound primarily by discs and facet joints with support from ligaments and muscles.

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The area where two bones combine is known as a joint. In the spine, the joint formed at the meeting of two vertebrae is known as a facet joint. Similar to joints everywhere in the body, they can swell and pinch nerves. Most people deem discs as a source of back pain, however, the facet joints are often to blame.

 

The Vertebral Column

The spinal column, better known as your spine, is a solid but flexible versatile structure. It bears the weight of your head and torso and permits movement in many directions. If it was a straight, inflexible pole, we’d walk like robots from bad B-movies. The amazingly flexible spine (moved and assisted by muscles) allows us to twist to hit a golf ball and bend over to tie our shoes.

The bony spinal column encases your spinal cord similarly to the medium around an electrical cord. It guards the all-important spinal cord, a collection of nerves which runs from your brain through your spinal column and branch out to the rest of the body.

Strictly speaking, the spinal column comprises of 34 bones. Twenty-four bones are articulated vertebrae bones (a singular bone is a vertebra). Located at the bottom of the spinal column are the remaining bones, the fused vertebrae of the sacrum and coccyx, which connect to your pelvis (hip bones). When people refer to the spine, they’re usually referred to the 24 vertebrae which form the elegant, double-S shaped line.

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Lumbar Vertebrae

 

Articulation is the motion which takes place between joints. For instance, particular facet joints in the spine permit up, down, side to side, and twisting movements.

The shape of vertebral bones changes down the column. There are differences, but there are many similarities. Every vertebra has a great, cylinder-shaped body and a vertebral arch. The arch can be further split into the spinous process (the bone which you can feel sticking out of your back) and facet joints which wing out to the sides. When observing a vertebra from a birds eye view, a vertebra has the appearance of a giant head with three pieces sticking out and a hole in the middle. Muscles, ligaments, and discs attach to numerous parts of a vertebra.

The area between the vertebral body and the arch is the spinal canal, which contains the spinal cord. Should this canal narrows, due to disease, for instance, it can squash the spinal cord and result in severe pain. Remember, your spinal cord is a bundle of nerves and nerves transmit pain signals. There are other openings amidst the stacked vertebrae. Holes known as intervertebral foramina are where nerve roots branch out of the spinal cord.

 

Intervertebral foramina are the holes which allow the nerves leave the spine. These foramina are the spaces in-between the upper and lower vertebral bodies. This space is usually fairly narrow. Again, should the space narrow due to trauma, disease, or deterioration, nerves can get squashed.

Lastly, let’s take a quick look at the spinal column as a whole. Doctors split the vertebral column into four main areas (cervical, thoracic, lumbar and sacral, from top to bottom). Each bone within an area has a number assigned to it. The spine is inherently curved. These curves allow the spinal column to be stronger, assist in absorbing shock from running and jumping, and help to maintain balance. The sizes of the curves do vary from individual to individual, but excessive curves can cause problems.

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Cervical spine: This is your neck, which comprises of seven vertebrae (C1-C7). The last one, C7 is the bone which usually sticks out the most. You should be able to easily feel it at the base of your neck, particularly when you push your chin down. Go for it; see if you can find it.

The cervical spine’s primary job is to bear the weight of your head. This is not as easy as it sounds, the head can weigh as much as 11 pounds! This is why how you hold your head makes so much difference. For lots of people who work with computers, a small but continuous forward jut of the head is not unusual. The result can convey forces deep into the neck and shoulders. Stress to your neck muscles will lead to a joint misalignment, which then pinches nerves. The final result? Ouch! Neck pain which also possibly radiating down into your arms.

Consider how many different directions you can move your head. There’s up, down, side to side, forward and back, and around. Thank the cervical vertebrae—specifically, the pivoting motion of C1—for all those wonderful movements. This is an advantage, most of the time at least. However, the highly flexible neck makes it particularly susceptible to injury, for instance whiplash when your head is driven forward due to impact from a rear-end car crash.

Thoracic spine: This is basically your rib-cage/mid-back area and contains 12 vertebrae (T1-T12). However, these vertebrae also attach to your ribs. The thoracic spine can move forward fairly easily; however it’s much more restricted when bending backward. This area of your back is not usually a big problem when it comes to back pain (most problems happen in the lower back). But, the mid-back can be excessively curved, this is known as kyphosis. It is often a result of poor posture—think slumping teenagers. Though it can be caused by disease. Whichever way it comes about, the excessive curve gives the person a hunchbacked appearance.

There can be some distress with kyphosis when caused by disease, but postural kyphosis doesn’t usually cause a lot of pain. However, exceptionally rounding your thoracic spine may also result in the head being pushed forward, which, as stated earlier, causes issues in your neck. The forward slouching also reduces in length the muscles in front of your torso and overstretches some back muscles. This results in discomfort when you attempt to sit up straight. The good news is that you can solve this with correct posture and proper exercise.

Lumbar spine: Say hello to your lower back, the region which causes pain for most people who suffer with back pain. But rather than you curse the day you were born with it, understand that the five lumbar vertebrae (L1-L5) have a huge job to do: they bear the majority of the weight of your body. As you can see in the photo, they are the largest vertebrae; they’re highly specialised for the job. These bones are designed for walking, running, sitting, and lifting. These activities, clearly, all have the potential for injury—you can reduce the risk by keeping your back and abdominal muscles strong and preserving proper flexibility throughout your back and body. Decent muscle conditioning further supports your lower back (and other parts of the spine), and with proper stretching, you can keep the area flexible as well.

An extreme curve in the lumbar region is referred to as lordosis, also known as swayback. This curve puts a large burden on your lumbar vertebrae. Lordosis is the result of disease, a movement of the spine such as bending the back, or bad posture. For most people, just sitting incorrectly can cause too much pressure on the lumbar spine. That’s why understand how your vertebrae should be aligned and taking the correct steps to make sure it happens can go a long way towards alleviating back issues.

Sacrum and coccyx (or tailbone): You may believe that spinal fusion is only done by surgeons, but nature does it too and providing that you’re over 30 years old, it’s happened to you. Your sacrum, the flat triangular bone located between your hips, used to be five vertebrae which have fused together. This fusion isn’t complete until you’re around 30. This part region the lowest and last curve in your spine. The curve, known as the lumbosacral curve, assists in bearing the brunt of your body weight.

Down from the sacrum is the tail end of your spine, known as the coccyx. Similarly, numerous fused vertebrae (generally 3-5) form the coccyx. Injury to this area can lead to coccydynia. Coccydynia is a painful condition due to swelling around your tailbone. Once the ligaments and tendons in this area have become inflamed, it’s very painful to sit. You can also get this pain from a fracture of the coccyx, which can happen if you fall and land right on your tailbone.

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