A bulged or herniated disc can narrow the opening and put pressure on the nerve. The intervertebral disc (described later) sits directly in front of the opening. ( Foramina is the plural term.) The two nerves that leave the spine at each vertebra go through the foramina, one on the left and one on the right. On the left and right side of each vertebra is a small tunnel called a neural foramen. It allows the ends of bones to move against each other smoothly, without friction.

Articular cartilage is a slick, rubbery material that covers the ends of most joints. The surfaces of the facet joints are covered by articular cartilage. The alignment of the facet joints of the thoracic spine allows freedom of movement as you twist back and forth or lean side to side. Where these knobs meet, they form a joint that connects the two vertebrae. A facet joint is made of small, bony knobs that line up along the back of the spine. There are two facet joints between each pair of vertebrae, one on each side of the spine. The facet joints are located on the back of the spinal column. ProjectionsД«etween the vertebrae of each spinal segment are two facet joints. These projections are called transverse processes. Bony knobs also point out from the side of the bony ring, one on the left and one on the right. You can feel these projections, called spinous processes, as you rub your fingers up and down the middle of your back. The laminae provide a protective roof over these nerve tissues.ДЄ bony knob projects out at the point where the two lamina bones join together at the back of the spine. When the vertebrae are stacked on top of each other, the bony rings form a hollow tube that surrounds the spinal cord and nerves. The lamina bones form the outer rim of the bony ring. Two lamina bones join the pedicles to complete the ring. Two pedicle bones connect directly to the back of the vertebral body. This protective ring of bone surrounds the spinal cord, forming the spinal canal. The increased size helps balance and support the larger muscles that connect to the lower parts of the spine.ДЄ bony ring attaches to the back of each vertebral body. Each vertebra increases slightly in size from the neck down. The main section of each thoracic vertebra from T1 to T12 is formed by a round block of bone, called the vertebral body. The lowest vertebra of the thoracic spine, T12, connects below the bottom of the rib cage to the first vertebra of the lumbar spine, called L1.Д®ach vertebra is made of the same parts. The large bump on the back of the lower part of the neck is the seventh cervical vertebra, called C7. Doctors often refer to these vertebrae as T1 to T12. The middle 12 vertebrae make up the thoracic spine. The kyphosis is shaped like a C with the opening in front. An outward curve, as in the thoracic spine, is called kyphosis. An inward curve in the spine is called lordosis.

The low back, also called the lumbar spine, curves slightly inward. The neck, called the cervical spine, curves slightly inward. From the side, the spine forms three curves.

Spine diagram