Back pain is a common medical complaint, with a vast number of complex causes and symptoms. The onset of back pain can often be due to subtle causes, such as poor posture. Symptoms can also be caused by abrupt trauma, such as the type sustained in a road accident or a fall, or a serious underlying problem, such as infection or osteoarthritis. This page briefly outlines the structure anatomy of the back and some of the symptoms and causes of back pain.
The structure of the back is divided between three distinct areas: the chest region, the lower back region and the base of the spine region. The chest region is medically referred to as the thoracic area of the back and the area of the spine running through it contains 12 thoracic vertebrae. Below the thoracic area is the lower back region, referred to as the lumbar area of the spine. This length of the spine contains five lumbar vertebrae, which are supported by the sacrum and coccyx at its base.
Between each vertebra is an intervertebral disc, made of firm but elastic tissue which acts as a shock-absorber, cushioning the spine during normal movements. There are also a pair of small joints between each vertebra called ‘facet joints’, which allow the spine to articulate and bend.
The spinal cord runs down through the middle of the vertebrae and branches off into smaller nerves at each vertebral level. The spinal cord is also protected by a fluid-filled sac, surrounded by different membrane layers, including the Pia Mater, Arachnoid Mater and Dura Mater. Just outside the Dura Mater is the epidural space, through which nerve roots leave the spinal cord. These nerve branches and roots travel to respective areas of the body, supplying connections to the brain and enabling it to locate sensations and pain in all areas of the body and to control motor function.
Causes of Back Pain
Poor back-muscle tone, muscle tension or spasms, back sprains, tears in ligaments or muscles and joint problems are some of the most common causes marking the onset of back pain. Bone strength and muscle elasticity naturally decrease with age. Consequently, the intervertebral discs begin to lose fluidity and flexibility, which in turn decreases their ability to cushion the vertebrae, leading to a variety of pain conditions.
A herniated disc, also referred to as a ‘slipped’ or ‘ruptured disc’, is a common cause of back pain. It occurs when a fragment of an intervertebral disc is pushed out of position and into the spinal canal through a tear or a rupture. As a result, the disc presses on the spinal nerves, producing severe pain. The vertebrae in the spine can also collapse in a condition commonly referred to as a ‘crushed spine’. This is usually common in patients above the age of 60. This kind of back pain is normally severe and will often erupt with minimal motion or a fall suffered by the patient.
Spondylolisthesis is a condition commonly found in young athletes. Pain is typically caused by a stress fracture in one of the vertebrae that make up the spinal column. Pyelonephritis arises when kidney stones lead to a basic kidney infection. This in turn causes pain, blood and painful urination, accompanied by one-sided lower back pain.
Shingles are typically characterised by a blistering rash and burning pain on the chest and the back. Shingles is the most common viral infection causing lower back pain.
Ankylosing Spondylitis is a form of arthritis that affects the lower back. Stiffness, soreness and swelling of the joints form the main causes of this type of back pain.
In pregnancy, ligaments around the uterus stretch and put pressure on the lower back, giving rise to pain which is sometimes very severe.
Some of the other causes of mild or severe back pain include nerve or muscle irritation, bone lesions and injury/trauma to the back. Certain degenerative conditions such as arthritis, osteoporosis, viral infections, irritations to joints and discs and congenital abnormalities in the spine are also known to cause lower back pain. Lastly, lifestyle deformities such as obesity, stress, poor physical condition, inappropriate posture and poor sleeping positions are the other common factors resulting in the onset of back pain.