The Spine: A Brief Anatomy Lesson

Humans are funny creatures. Unlike most animals, we walk upright, but we have no tails for balance. We are capable of incredible athletic feats, but we are still frequently subject to back pain and other spinal issues. The explanation for these phenomena largely lies in the structure of our spines. Take a look at these anatomic facts for insight into your own back.

Basic Structure

As you probably know, the spinal column houses the spinal cord – a major component of the central nervous system. The spinal cord carries the majority of motor and sensory impulses to and from the brain and the rest of the body. Your spinal column protects your spinal cord, so it must be tough. But your spine also needs to be flexible so that you bend forward, flex backward, and rotate at your hips.

Although it is often called the backbone, your spine actually consists of 33 separate vertebrae. Most of these vertebrae are separated by facet joints that allow your spine some degree of flexibility. The vertebrae also contain holes called intervertebral foramina. The spinal nerves exit these holes and progress throughout your body. Intervertebral discs made of cartilage are also situated between your vertebrae. These discs can absorb shock and are somewhat flexible.

Spinal Regions

The human spine is divided into five regions. The cervical spine in the neck area has seven vertebrae. C1, the first cervical vertebra, is also called the atlas since it “holds” the skull. C2 is known as the axis and plays a major role in allowing you to rotate your head. This region is the most susceptible to whiplash injuries.

The thoracic vertebrae are in your torso. There are 12 thoracic vertebrae, and these serve as attachment points for your ribs. Next are the five lumbar vertebrae of the lower back. Many of the spinal nerves that exit here innervate the pelvic area and legs.

The next two spinal areas are the sacral and coccygeal vertebrae. These vertebrae are fused and do not offer much flexibility. However, many people experience problems with the L5-S1 (fifth lumbar and first sacral) vertebral junction. The coccygeal vertebrae are fused to form the coccyx, also known as the tailbone.

Spinal Curvature

The human spine is far from a straight line. In fact, the natural curvatures of our spines allow us to walk, run, jump and also mitigates the shock from impacts on our feet. There is a gentle curve encompassing the cervical vertebrae and top couple of thoracic vertebrae. This is called the lordotic curve.

The next curve, the kyphotic curve, extends to the bottom of the thoracic vertebrae. It is much more pronounced than the lordotic curve. Next is the lumbar curve, beginning at the bottom thoracic vertebra and extending throughout the lumbar region. Women typically have a more extreme lumbar curve than men.

Proper spinal curvature is essential for balance, motor ability, and pain-free activity. Spinal curvature is one of the many aspects assessed and addressed by professional chiropractic care, along with factors like unobstructed spinal nerves and facet joint health.