“Standing up when everyone expects you not is the best way to show you have a backbone”
According to the World Health Organization, as of November 26, 2019 musculoskeletal conditions are the leading contributor to disability worldwide, with low back pain being the single leading cause of disability globally. In addition, according to spine-health.com, up to 20% of all injuries that occur in sports involve an injury to the lower back or neck. So if you’re reading this, more likely you have experienced aches, pain or even injury to your spine, especially if you are involved in sports.
In this article, our objective is to tell you the basic anatomy of the spine. Then, we shall describe the function of the neck and low back in terms of their movement. We will also discuss the capacities and limitations of the neck and low back and how it leads to the common injuries. Lastly, we will impart simple rehab and recovery strategies that will ultimately help you to prevent injury or re injury.
Let us first discuss basic spine anatomy. We will focus on three anatomical systems namely skeletal, nervous and muscular.
The spine’s skeletal system comprises of its vertebral bones and its arrangement. There are a total of 34 vertebral bones, these bones have 5 types, namely 7 Cervical (neck), 12 Thoracic (Upper Back), 5 Lumbar (low back), 5 fused Sacral (tail bone) and 5 fused Coccyx. They are stacked together and arrange so as it forms two curvature, namely Lordosis curve, which is formed at the cervical and lumbar vertebra, and the Kyphosis curve, which is formed by the Thoracic and Sacral vertebra. Refer to the figure below
The function of the vertebral bones is to bear weight of the upper body. They provide points of attachment for muscles and ligaments. They protect the spinal cord. They also provide the exit points for spinal nerves. Each vertebral bones that are not fused in separated by Intervertebral Disc, which are cushions of shock absorbers between vertebral bones. See figure below.
Let us know discus the spine’s Nervous System. It is comprised of the Brain, Spinal cord and peripheral nerves. The brain, found inside the skull, continues down the brain stem to become the spinal cord. The spinal cord then passes inside the vertebral canal which is found in each vertebral bone that ends at the sacrum. The spinal cord also branches out from its sides through each vertebral bone via intervertebral foramen as Nerve roots to become peripheral nerves. The peripheral nerves branches out to cover all areas of our body. Refer to diagram below.
This whole systems is set up to receive sensory input and transmit motor command all over the body. This is mapped out in different areas which are called Dermatomes and Myotomes.
A dermatome is an area of skin in which SENSORY nerves derive from a single spinal nerve root. You will notice from the diagram below that each vertebral level will represent a specific sensory area of the body.
A Myotome is representation of a group of muscles innervated by the ventral nerve root of a single spinal nerve. So like a dermatome, a myotome will have a specific muscle group and movement represented per vertebral level as seen below.
I hope at this point you can start to appreciate the connection between your skeletal and nervous system anatomy to common low back and neck pain symptoms. Now let us talk about the spine’s Muscular system.
The muscular system around the spine can be divided into superficial and deep muscles, where in the deep muscle have two distinct muscle groups.
The superficial muscle functionally belongs to the upper limbs but are situated on the back (posterior) aspect of the trunk also known as “immigrant” muscles.
The deep muscles, or “intrinsic” muscles are muscles that act specifically to the vertebral column. Refer to the figure on the right to see the different muscles and their organization.
The function of the deep muscles is to support the spine and hold it upright. They also control movement during rest and activity.
One group of the deep muscles are the Erector Spinae. They provide resistance that assist in the control action of bending forward at the waist. They are also powerful extensors to promote the return of the back to the erect position, thus the name “Erector Spinae”. Refer to the figure below.
The other group of deep muscle are the Abdominal muscles. This group of muscle function to support the trunk. They allow movement and hold organs in place by regulating internal abdominal pressure. They also keep your body stable and balances and lastly they protect your spine, Refer to figure below.