The human spine is made up of 33 separate bones, called Vertebrae, connected together and held in place by muscles and ligaments. The connective muscles in the back can be split into two groups: 'Flexors' and 'Extensors', and both have their own important role to play in keeping the spine protected and allowing it to function alongside the other parts of the body.
Attached to the back of the spine, extensor muscles stabilise your spine, and allow us to stand up-right and lift objects; but ideally they should not be used too often to perform the latter as this can result in both short-term and long-term injuries. Flexor muscles are positioned in front of the spine and include the abdominal muscles. These are responsible, as the name would suggest, for allowing us to flex, but also to bend over forwards and control the lower areas of the spine (Lumbar & Sacrum). The flexors are also an integral part of lifting properly, which involves keeping your back up-right whilst lifting with your legs.
The aforementioned ligaments that accompany the muscles are strong, fibrous bands that are responsible for keeping the vertebrae properly aligned and held together properly. Also present to protect the individual discs for external dangers and from each other, there are a trio of essential ligaments in the spine – the 'Ligamentum Flavum', the 'Anterior Longitudinal Ligament' and the 'Posterior Longitudinal Ligament' – that are collectively responsible for preventing unnecessary spinal movements and for connecting the individual vertebrae to one another.
As we mentioned previously, there are 33 vertebrae that make up the spinal column, and these 33 bones are grouped into 5 distinct regions: Cervical, Thoracic, Lumbar, Sacrum and Coccyx.
- Cervical – Made up of the first 7 vertebrae, and known individually as C1, C2, C3, etc., the cervical region of the spine is found in the neck and its primary purpose is to support the weight of the head. The approximate weight of a human head is between 5 and 6 kilograms, which is a just little bit less than a stone, and the brain contributes 1.5kg of this weight. The vertebrae that make up the Cervical region are granted the greatest range of movement because of C1 and C2, which are specially adapted as they also have to connect to the skull.
- Thoracic – Comprised of the most vertebrae (T1 to T12), the Thoracic region of the spine is located behind the chest (AKA the 'Thorax'). T1 to T12 are granted a very limited range of motion, as it's their job to support the rib cage and protect the heart and lungs.
- Lumbar – Designed to bear the body's weight, the 5 vertebrae that make up the lumbar region cover the lower back. L1 to L5 are thicker and more sturdy than the other vertebrae, as it is also their job to absorb the pressure and strain exerted on the body when lifting and carrying heavy objects.
- Sacrum – The 5 vertebrae that make up the Sacrum, S1 to S5 are fused together and are tasked with connecting the spine to the Iliac (or 'hip bone').
- Coccyx – Also known as the tail bone, the remaining 4 vertebrae are also fused together, and are there to provide the ligaments and muscles on the pelvic floor something to attach themselves on to.
Now that you know how your spine fits together, find out why spinal health is important and what steps you can take to look after it.