The spine can be divided into five different regions, from top to bottom:
- 7 cervical vertebrae support your head and neck, allowing you to nod and shake your head.
- 12 thoracic vertebrae are attached to your ribs, forming part of the ribcage.
- 5 lumbar vertebrae carry most of the weight of your upper body.
- the sacrum, made up of 5 fused vertebrae, forms the backwall of your pelvis.
- the coccyx, made up of 4 fused vertebrae, is an evolutionary remnant of the tail found in most other vertebrates.
Now let’s try out a small experiment so that you can actually feel and touch the different parts of your spinal column.
Lie down on your back on a soft surface, in the most gracious supine position; that is, arms extended in a cross and legs lying straight out. Lift one leg up towards the ceiling, up to a 90 degrees hip flexion. Then rise the other. Your derriere is still glued to the ground.
Slowly, start moving your legs back, down towards your head. Bend your knees as you go. Your arms do likewise, carefully folding around your legs. Voilá. You’ve transformed yourself into a human gumball. Your knees are bent towards your ears, your arms are hugging your legs closely in. The weight of your body is on your upper back and shoulders, without putting pressure on the neck. Without knowing it, you have articulated your vertebrae one after the other, and are now resting in this position.
Now count to 60 and start rolling down. Slowly, carefully, vertebrae by vertebrae. Always keep your back rounded, as to not hurt your spine.
Feel how your vertebrae slowly articulate one after the other and place themselves on the floor. First the cervical spine, then the dorsal spine, lumbar spine, sacrum and coccyx. You legs finally return to the floor, with control.
See? This is what your vertebral spine is all about. These are your vertebrae cooperating in the smooth extension and flexion of your spine.
Joints of the Spine
Even though the joints between individual vertebrae aren't that flexible, when these babies get together... wow!
Just bend down to tie your shoes to see what I’m talking about. The wide range of movement of your spine, that allows you to arch backwards, bend forwards and twist from side to side, is the result of coordinated teamwork. Way to go vertebrae!
Nevertheless, this long row of bones needs to be stabilised and remain controlled.
And that’s where the joints, ligaments and tendons come in.
Each vertebrae that forms the spine is joined to the others from 5 different points. These are:
joints between the vertebral bodies: intervertebral discs
joints between the facet surfaces: facet joints
associations between the laminae: yellow ligaments
associations between the spinous processes: interspinous ligaments
associations between the transverse processes: intertransverse ligaments
Intervertebral discs
Sandwiched between your vertebrae are pads of tough, fibrous cartilage called intervertebral discs that cushion your vertebrae and absorb shocks. There is one disc between each vertebra.
Each disc has a strong outer ring called the annulus, and a soft, jelly-like center called the nucleus pulposus.
The mushy nucleus of the disc has a very high water content. This water helps the disc act like a shock absorber... sort of like a waterbed mattress!
Facet joint
The facets are articulate surfaces that join each vertebrae to the one above it and the one below it. There are two facet joints between each pair of vertebra, one on each side. These joints allow for most of the spine’s flexibility.
Yellow ligaments
There is one on each side. It goes from the top of one laminae to the bottom of the other. It helps close the spinal canal.
Interspinous ligaments
From the top of one spinous process to the bottom of the other. It continues covering the back of the spinous process, forming a single, long strand that connects all the vertebrae together. It thickens around the cervical area, protecting this delicate region and allowing the insertion of neck muscles.
Intertransverse ligaments
One on each side, this ligament goes from the top of one transverse process to the bottom of the other.
