The spine is also known as the backbone, which is made up of several vertebral bones with cushioning intervertebral disc in between them. The spine is designed to give stability and smooth movement and as well as a corridor for the protection of delicate spinal cord and nerves. It is supported by muscle, tendons, and ligaments and innervated by nerves that branch out from the centrally placed spinal cord. Having a well-functioning healthy back is essential for our mobility and ability to participate in various activities. Understanding the basic anatomy of the spine enhances your Ability to understand the various condition of the spine and treatment options with your surgeon.

Spine anatomy will be discussed in three sub-headings

• Vertebral bones and joints
• Ligaments and muscle
• Spinal cord and spinal nerves

Vertebral bones and joints

The entire spinal column from the head to tail is made up of series of 33 individual vertebrae and 24 intervertebral discs stacked alternatively upon each other. The last 9 vertebrae (sacrum and coccyx) are naturally fused to each other.

The vertebral column can be divided into 5 regions

• Cervical spine: 7 vertebrae of the neck (C1-C7)
• Thoracic spine: 12 vertebrae of the mid-back (T1-T12)
• Lumbar spine: 5 vertebrae of the lower back (L1-L5)
• Sacrum: made of a fusion of 5 vertebrae
• Coccyx: made of a fusion of 4 vertebrae, also known as tail bone

A normal vertebral column creates a graceful, double-S curve when viewed from the side of the body. The cervical vertebrae gently curve inward, while the thoracic spine curves gently outward, followed by the lumbar spine, which curves inward again. This structure gives the spinal column great strength and shock-absorbing qualities.

Parts of a typical vertebra

The vertebrae are similar in their general characteristics from one region to another except their sizes and some characteristics may vary. A typical vertebra consists of

• Vertebral body: anteriorly, which supports most of the load while standing and provides a platform for the attachment of intervertebral discs.
• Pedicle: two cylindrical shape bony projections connecting the front and back of the vertebra.
• Lamina: Lamina is a pair of flat arc bone that forms the roof of the spinal canal and provides support and protection to the spinal cord at the back
• Spinous process: these are bony projections that arise at the right angles to the midline of the lamina and these can be felt when touching the back.
• Transverse process: these are the bony protrusions located at the junction of the pedicle and lamina. They provide a place for the attachment of the back muscles.
• Spinal Canal: This is the tunnel formed at the center of the vertebra for the passage of the spinal cord.
• Facet Joints: These are paired articular processes found at the vertebral arch. Each vertebra consists of two pairs of facet joints. One pair is called the superior facet joint which articulates with the vertebra above and other inferior facets articulate with the vertebra below.