The spine is one of the most important structures within the human body. It provides stability, support as well as houses and protects the spinal cord.
‘Backing’ you up – Literally
Unfortunately, as a society we don’t take as much care of our spines as we should. This has led to misconceptions about the structural integrity and strength of the spine. A lot of fear surrounding injuries in the back and neck is the result. The spine, however, like numerous other structures within the body, is capable of adapting and strengthening. The correct input makes correcting your spinal alignment and function very possible. Many people think that surgery is inevitable when you injure your back or neck or when your X-rays shows some abnormalities – guess what, surgery is only the last option. By being informed, you will be able to make the right decision about your back, spine and health. We need to take the time to become more aware and appreciative of the strength and resilience of our spines.
Anatomy of the Spine and Pelvis
There are 4 sections of the spine: Cervical, Thoracic, Lumbar and the Sacrum. Each section has features that are specific to the function in that area. This includes the shape of the bones (called vertebrae) and thickness of the inter-vertebral discs. There are 24 vertebrae in the spine, and we name them by using either a C,T or L and a number to determine their location.
Before we look at the specific bones and sections of the spine it is important to understand the basics of the bones. This includes how they fit together with the discs and each other to provide the strong and flexible spinal column.
As a general rule, each Vertebra has:
- A vertebral Body
- Vertebral foramen (hole) or spinal canal that houses the spinal cord
- 1 Spinous process, the bumps that you can feel in your back and neck
- 2 Transverse (side) processes and 4 articular facets
- A Disc between each vertebra
- Facet joints between the vertebrae
In between each vertebra there is a spinal disc. The spinal discs have a dual function as they are both shock absorbers and ligaments that connect the vertebra to each other.
The facet joint serves as a joint between each vertebra to the ones above and below. This joint allow both flexibility and extra support on the sides of the vertebrae as the spine moves. There are 2 facet joints – one on either side of the vertebral body.
The Vertebral foramen is the hole in the vertebrae that allows the spinal cord to run through it – that is after all why we have a spine. To protect the spinal cord. There are nerves that sprout from the spinal cord, that exit at the side of each vertebrae, which supplies the rest of the body and allows movement.
The Neck is called the Cervical spine which has 7 vertebral bones. We refer the the cervical spine in anatomical terms C1-7.
It is specialised to support and move the head and is the most mobile part of the spine. Unlike the rest of the spine the bones have additional 2 foramina (holes) for blood vessels, which supply the brain. The vertebral bodies are smaller because the vertebral foramen is bigger as the spinal cord is thickest in the neck.
The first 2 vertebrae (C1 and C2) are significantly different to all the others.
The Atlas or C1 vertebra connects to the base of the skull. It is named after the ancient Greek god, who was said to support the world on his shoulders.
C2 is called the Axis, as it has an extra process or dens. The dens acts as an axis or point of rotation for the atlas and head. Due to the anatomy you can move your head to the side without moving your whole neck. C1 and C2 do not have vertebral bodies or spinal discs to allow for this movement.
The Thoracic spine is formed of 12 vertebrae (T1-12) with 12 pairs of corresponding ribs attaching to each one. Thoracic vertebrae are medium in size compared to the smaller cervical and larger lumbar vertebrae. They have 2 extra facets on the vertebral body for the rib attachments. The thoracic spine is the least mobile of all the spinal sections, as the discs are thinner and the rib cage restricts movement.
The Lumbar spine is made of 5 vertebrae (L1-5). They are the simplest but also the sturdiest vertebrae, because they have large vertebral bodies, processes and discs to carry the weight of the head, arms and trunk.
The Spinal cord ends at level L1/2, with nerves spreading out from L2-5 in a ‘horse-tail’ manner.
The Lumbar spine is not a mobile as the cervical spine, but has significantly more movement than the thoracic spine.
Sacrum and Pelvis
The Sacral spine is the final section of the spine and consists of 5 fused vertebrae. There are no discs or facet joints because of the fusion but there are still neural foramina. These allow the nerves to exit the spinal column to the lower half of the body.
The sacrum and pelvic bones form the pelvic girdle which directly supports both the lumbar spine and the hips. This means that movements at the pelvis have a direct effect on the lumbar spine and therefore the rest of the spine. The coccyx is also considered as part of the spine. However, it functions more as a connection point for muscles, ligaments and tendons than as part of the bony structural support.
The spine forms 4 curves that allow it to be both flexible and to withstand gravitational forces on the body as seen in the picture above. To understand the movement of the curves – check out the biomechanics article to see this in action.
The first type is the primary curves, which are present from birth. They are the kyphotic curves (moving towards the back) in the thoracic spine and sacrum. The secondary lordotic curves (moving towards the front) of the cervical and lumbar spines form as a baby strengthens and learns to lift its head and later stand.
The Pelvis and Movement
The pelvis has four main movements; anterior tilt, posterior tilt and a lateral drop or lift on both sides. The movement and resting position of the pelvis has a direct effect of the lumbar spine. An anterior pelvic tilt causes an increased lordosis and a posterior pelvic tilt decreases the lordosis. Read all about your Posture here.
Along with the rest of our bodies; the spine grows, changes and adapts as we age. You might be familiar with the word – degenerative changes. However, this description doesn’t do the body justice. While it is true that the discs, joints, ligaments and bones do change as we age, it does not have to be bad.
The term degeneration implies that there is a problem, but most people have some degeneration in their joints as they age. Degeneration can be caused by an increase in mechanical stress, which is caused by poor posture, continually lifting heavy objects incorrectly or weakness of the surrounding supportive muscles. Sustaining unnatural positions for long periods, such as using a cellphone, also causes stress. Genetics may play a role in spinal changes, but just because someone in your family had surgery or ‘has a bad back’, doesn’t mean you will too.
The most important thing to remember is that you need to look after your spine. Ensuring your posture and biomechanics are correct for your lifestyle and activities are important. Movement is the most important medicine for the spine as well as the rest of your body. If you are concerned or would like to know more about how you can best look after yourself, Book an appointment for an assessment and action plan.