The section of the spinal column called the Thoracic Spine begins below the cervical spine (C7, neck), roughly at shoulder level and continues downward until it reaches the first level of the low back (L1, lumbar spine). Twelve vertebrae, numbered T1 through T12 from top to bottom, make up the thoracic spine. When viewed from the side, a normal forward curvature called Kyphosis (or kyphotic curve) is seen.
Fig.1. Its attachment to the rib cage affords the thoracic region of the spinal column greater stability and strength.
Because the ribs attach to the thoracic spine’s vertebrae, this section of the spine is strong and stabilising, with less range-of-motion than the cervical (neck) levels. While the thoracic spine is less prone to injury than other sections of the vertebral column, it is the most common location for vertebral fracture due to osteoporosis. Scoliosis and abnormal kyphosis are other thoracic spinal disorders.
Why take time to learn about thoracic spinal anatomy? Because it can help you better understand possible causes of upper back and midback pain, the doctor’s diagnosis and why simple lifestyle changes can help keep your midback healthy.
Thoracic Spine Bone Basics
The thoracic spine helps support the body’s torso and chest areas and provides an attachment point for each of the rib bones, except the 2 at the bottom of the ribcage.
Like most other spinal vertebrae, the thoracic vertebral bodies are rounded. Bony arches project from the back of each vertebral body, forming a hollow protective space containing the spinal cord. Thoracic facet joints are paired at the back of each vertebrae and allow limited spinal movement.
Fig. 2. The thoracic spine is the longest section of the spinal column.
Multipurpose Thoracic Spinal Discs
A fibrous pad of tissue called an intervertebral disc is held in place by a strong endplate attachment between each level’s upper (superior) and lower (inferior) vertebral body. Each disc acts as an interbody spacer, creating disc height or space between its upper and lower vertebrae. This space creates open nerve passageways called foramen or neuroforamen at both sides. Nerve roots (or rootlets) branch off the spinal cord and exit the spinal canal through neuroforamen.
Soft Thoracic Supporting Structures Allow Movement Within Limits
Common to the entire spinal column are ligaments, tendons, and muscles. These soft tissues attach to the bones and discs and work together to help stabilise the midback at rest and during movement.
- Ligaments are strong bands of fibrous tissue that connect and protect vertebrae and discs, provide spinal stability, and help prevent excessive movement.
- Muscles help hold the body upright and allow spinal flexion (bend forward), and rotation (twist from side to side).
- Tendons are strong fibrous tissue that attaches muscle to bone.
Role of Thoracic Nerves
Twelve pairs of thoracic nerve rootlets branch off the spinal cord and through the foramen to innervate or supply sensation (feeling) and function (movement) to specific areas of the body. These nerves feed the midback and chest regions, and transmit signals between the brain and major organs, including the lungs, heart, liver, and small intestine.
Types of Thoracic Spinal Disorders
- Osteoporosis increases the risk for thoracic spinal fracture. A common type is a vertebral compression fracture (VCF) that can cause one or more bony bodies to flatten or become wedge-shaped, resulting in spinal cord and/or nerve compression. Sudden and acute back pain is associated with a VCF.
- Different types of scoliosis – an abnormal side-to-side curvature of the spine – is well known to develop in the thoracic spine and may cause spinal deformity.
- Abnormal kyphosis is an exaggerated amount of forward thoracic spinal curvature. While humpback is not a kind expression, it aptly describes the appearance of a kyphotic deformity. Types of kyphosis include congenital (appearing at birth), posture related, or Scheuermann’s disease.
Fig.3. Scoliosis and kyphosis are 2 types of conditions caused by abnormal curvature of the thoracic spine.
- Metastatic cancer (e.g. Travelling from a breast, lung) is a foremost cause of spinal tumours that can develop in the thoracic spine, potentially leading to structural deterioration.
While cervical or lumbar disc herniations are common, thoracic disc herniation is not. This is because of your thoracic spine’s strength and stability created by its attachments to the ribcage.
Maintain your Thoracic Spine
- Ask your doctor for stretches and exercises appropriate for you to keep your core and midback musculature strong to help prevent injury during flexion, extension, and rotation type movements.
- Be aware of your posture; use good body mechanics.
- If you smoke or vape, consider quitting.
- Learn your personal risks for osteoporosis and put a preventative bone density maintenance plan in place with your healthcare providers’ help.
Written by Stewart G. Eidelson, MD
Cannington Chiro Services
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