The hollow tube formed by the bony rings on the back of the spinal column surrounds the spinal cord. A facet joint sits in the back of the foramen on each side.īone spurs that form on the facet joints can also encroach into the space of the foramen, narrowing the hole and pinching the nerve. A bulged or herniated disc can encroach on 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 a small tunnel is formed from the stacking of vertebrae. The cartilage allows the bones to move against each other smoothly, without friction. Articular cartilage is a slick, rubbery material that covers the ends of the bones in a joint. 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, move back and forth, or lean side to side. There are two facet joints between each pair of vertebrae, one on each side of the spinous process. The facet joints are located on the back of the spinal column. The 11th and 12th ribs connect only to the vertebral body and are therefore freer to move.īetween the vertebrae of each spinal segment are two facet joints.
In the thoracic spine, all the ribs except the 11th and 12th ones attach onto these transverse processes as well as attaching onto the thoracic vertebral body. These projections are called transverse processes. Bony knobs also project 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.Ī bony knob projects out at the point where the two laminae join together at the back of the spine.
When the vertebrae are stacked on top of each other, this bony ring forms a hollow tube that surrounds the spinal cord and nerves. The laminae form the outer portion of the bony ring. Two laminae join the pedicles to complete the ring. Two bony extensions called pedicles 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.Ī bony ring attaches to the back of each vertebral body. Each vertebra increases slightly in size from the neck down. A round block of bone, called the vertebral body, forms the main section of each thoracic vertebra from T1 to T12. 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.Įach vertebra is made up of the same parts. It sits on top of T1, the next large bump. The first large bump on the back of the lower part of the neck as you feel down your spine 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.
A kyphosis is shaped like a "C" with the opening at the front. An outward curve, as in the thoracic spine, is called a kyphosis. An inward curve in the spine is called a lordosis. The low back, also called the lumbar spine, curves slightly inward. The neck, called the cervical spine, curves slightly inward. The spinal column is the body's main upright support.įrom the side, the spine forms three curves. Vertebrae are stacked on top of one another to create the spinal column. The human spine is made up of 24 spinal bones, called vertebrae. This section highlights important structures in each category. The important parts of the thoracic spine include: