The vertebral column, also called the spinal column, spine, or backbone, is a flexible column of bones that extends from the neck to the tail in vertebrate animals. It is part of the axial skeleton and encloses and protects the spinal cord within the spinal canal. The vertebral column also supports the weight of the body, forms the central axis of the body, and allows movement and posture.
The vertebral column consists of a series of bones called vertebrae, which are separated by intervertebral discs made of fibrocartilage. The number and shape of vertebrae vary among different species, but in humans there are normally 33 vertebrae. The vertebral column can be divided into five regions: cervical (7 vertebrae), thoracic (12 vertebrae), lumbar (5 vertebrae), sacral (5 fused vertebrae), and coccygeal (4 fused vertebrae).
Each vertebra has a common structure that includes an anterior vertebral body, a posterior vertebral arch, and several bony projections that serve as attachment sites for muscles and ligaments. The vertebral body is the weight-bearing part of the vertebra, while the vertebral arch forms a ring around the vertebral foramen, a hole that accommodates the spinal cord. The bony projections include spinous processes, transverse processes, pedicles, laminae, and articular processes. The spinous processes are palpable along the midline of the back. The transverse processes project laterally from the vertebral body and may articulate with ribs in the thoracic region. The pedicles connect the vertebral body to the transverse processes. The laminae connect the transverse and spinous processes. The articular processes form joints between adjacent vertebrae.
The vertebral column has four normal curves that help to maintain balance and absorb shock: cervical lordosis (concave posteriorly), thoracic kyphosis (convex posteriorly), lumbar lordosis (concave posteriorly), and sacral kyphosis (convex posteriorly). These curves are present at birth or develop during infancy and childhood. Abnormal curvature of the spine can result from various conditions, such as scoliosis (lateral curvature), kyphosis (excessive convexity), lordosis (excessive concavity), or spondylolisthesis (forward displacement of one vertebra over another).
The vertebral column is subject to various injuries and diseases that can affect its function and cause pain or disability. Some common examples are intervertebral disc herniation (protrusion of the disc material into the spinal canal or nerve roots), spinal stenosis (narrowing of the spinal canal or nerve openings), osteoarthritis (degeneration of the articular cartilage and bone spurs), osteoporosis (loss of bone density and strength), spinal fractures (breaks in the vertebrae due to trauma or osteoporosis), spinal infections (inflammation of the vertebrae or discs due to bacteria or fungi), spinal tumours (abnormal growths of cells in or around the spine), and spinal cord injury (damage to the spinal cord due to trauma or disease).
The Spine
The human spine is a complex anatomic structure that is the scaffolding for the entire body. It provides several important functions, including protecting the spinal cord and nerves and structural support for the body, allowing us to stand upright. The spine supports about half the weight of the body. The human spine consists of three main sections: cervical, thoracic, and lumbar. Each spinal section has its own healthy curvature. For preserving the spine’s overall health and function, maintaining those curves is important, and the vertebrae and intervertebral discs play integral roles.
What is the spine?
Your spine, often known as your backbone, is the central support structure of your body. It connects various sections of your musculoskeletal system. Your spine allows you to sit, stand, walk, twist, and bend. Back injuries, spinal cord diseases, and other issues can all damage the spine and produce back pain.
What are the parts of the spine?
A healthy spine has three natural curves that form a S shape. These curves absorb shocks to your body and protect your spine from harm.
Your spine is made up of several separate parts:
- Vertebrae: The spine has 33 stacked vertebrae (small bones) that form the spinal canal. The spinal canal is a tunnel that houses the spinal cord and nerves, protecting them from injury. Most vertebrae move to allow for a range of motion. The lowest vertebrae (sacrum and coccyx) are fused together and don’t move.
- Facet joints: These spinal joints have cartilage (a slippery connective tissue) that allows vertebrae to slide against each other. Facet joints let you twist and turn, and they provide flexibility and stability. These joints can develop arthritis and cause back pain or neck pain.
- Intervertebral disks: These flat, round cushions sit between the vertebrae and act as the spine’s shock absorbers. Each disk has a soft, gel-like centre (the nucleus pulposus) surrounded by a flexible outer ring (the annulus). Intervertebral disks are under constant pressure. A herniated disk can tear, allowing some of the nucleus’ gel substance to leak out. Herniated disks (also called bulging, slipped or ruptured disks) can be painful.
- Spinal cord and nerves: The spinal cord is a column of nerves that travels through the spinal canal. The cord extends from the skull to the lower back. Thirty-one pairs of nerves branch out through vertebral openings (the neural foramen). These nerves carry messages between the brain and muscles.
- Soft tissues: Ligaments connect the vertebrae to hold the spine in position. Muscles support the back and help you move. Tendons connect muscles to bone and aid movement.
What are the spine segments?
The 33 vertebrae make up five distinct spine segments. Starting at the neck and going down toward your buttocks (rear end), these segments include:
- Cervical (neck): The top part of the spine has seven vertebrae. These neck vertebrae allow you to turn, tilt and nod your head. The cervical spine makes an inward C-shape called a lordotic curve.
- Thoracic (middle back): The chest or thoracic part of the spine has 12 vertebrae. Your ribs attach to the thoracic spine. This section of the spine bends out slightly to make a backward C-shape called the kyphotic curve.
- Lumbar (lower back): Five vertebrae make up the lower part of the spine. Your lumbar spine supports the upper parts of the spine. It connects to the pelvis and bears most of your body’s weight, as well as the stress of lifting and carrying items. Many back problems occur in the lumbar spine. The lumbar spine bends inward to create a C-shaped lordotic curve.
- Sacrum: This triangle-shaped bone connects to the hips. The five sacral vertebrae fuse as a baby develops in the uterus, which means they don’t move. The sacrum and hip bones form a ring called the pelvic girdle.
- Coccyx (tailbone): Four fused vertebrae make up this small piece of bone found at the bottom of the spine. Pelvic floor muscles and ligaments attach to the coccyx.
Characteristics of the Spine
The individual joints in the spine allow only limited movement but when the vertebrae move together, the spine can bend in all directions, as well as rotate.
The specialised joints in the neck (cervical vertebrae) allow a much greater specific movement e.g. nodding the head and looking from side to side.
As the joints and discs get larger, the range of movement becomes more restricted, especially in the lumbar region where only small ranges are possible.
The spine has to absorb shock and force and therefore has to be very strong. In order to manage this shock and force it is curved in four places.
Misalignment of the spine can lead to postural problems and back pain.
Alignment and abnormalities of the spine
Abnormalities of the spine are conditions that affect the shape, alignment, or function of the backbone. They can cause pain, neurological problems, and mobility challenges.
- Neutral spine is a gentle “s” space with the spine passing either side of the centre line, this “s” shape allows the spine to bend and flex to absorb the forces associated with movement. The thoriac in the upper and mid back form the large curve of the “s” and the lumbar, sacrum and coccyx in the lower spine moving through the pelvis.
- Kyphosis – abnormal curvature of the thoracic vertebrae where the vertebrae are rounded so that the shoulders sit in front of the hips. Strengthening the erector spinae, rhomboids and mid/low traps and stretching out the upper traps, abdominals and pectoral muscles normally helps.
- Lordosis – abnormal curvature of the lumbar vertebrae where the lumbar curve is increased tilting the pelvis forwards. Strengthening the core, glutes and abdominals and stretching the erector spinae normally helps.
- Scoliosis – abnormal curvature of the thoracic vertebrae where the spine leans to one side rather than running centrally up the mid-line of the back.
- Flat back – occurs when the natural lordotic curve is lost and flattens and the pelvis is tucked underneath the bottom. Strengthening the core, glutes and quads and stretching out the hamstrings normally helps.
Good exercise technique aims to maintain normal spinal alignment, through normal range of movement.
Through exercise we can educate our participants about posture, lifting etc. and provide exercises and stretches to improve posture and support for the spine.
Poor posture can lead to:
- Poor balance.
- Collapsing technique e.g. running or landing.
- Slower times
- Less power.
- Increased injuries, aches and pains.
Strong back muscles can protect your spine and help you avoid back problems. Try to do back-strengthening and stretching activities at least twice a week. Planks, for example, strengthen the core (abdominal, side, and back muscles) to provide your spine additional support.
Other safeguards include:
- Bending your knees and keeping your back straight when lifting items.
- Losing weight, if needed (excess weight strains your back).
- Maintaining a good posture.
