About the Spine

The Cervical Spine

What are the structures of the cervical spine?

The cervical spine consists mainly of the vertebrae or bone of the spine with a disc in between each bone. There are seven cervical vertebrae (referred to as C1-7). The main part of the vertebra is called the body and is located at the front. The disc is located between the vertebral bodies. Each disc is referred to by the bones between which it sits. For example, the C5/6 disc is located between the C5 and C6 vertebral bodies.

Behind the vertebral bodies there is a ring of bone that contains the spinal cord. The back of this ring is made of the lamina and spinous processes to which the muscles are attached. The spinal cord is surrounded by spinal fluid and is enclosed in a sac called the dura. At each level a nerve root emerges from the spinal cord exits the spine through a hole between each bone called the intervertebral foramen. That nerve root will supply feeling (sensation) to an area of the arm and will also supply muscles that perform different movements.

cervical spine structure

The disc is made of two main elements. The first is the annulus fibrosis. This is a strong outer layer made of criss-crossing fibres. The inside of the disc, or nucleus pulposus, is the soft gel-like centre which normally provides the cushioning function of the disc.

The Lumbar Spine

Spine

What is the anatomy of the lumbar spine?

The lumbar spine consists mainly of the vertebrae or bone of the spine with a disc in between each bone. There are five lumbar vertebrae (referred to as L1-5). The main part of the vertebra is called the body and is located towards the front. The disc is located between the vertebral bodies. Each disc is referred to by the bones between which it sits. For example, the L4/5 disc is located between the L4 and L5 vertebral bodies.

Behind the vertebral bodies there is a ring of bone that contains the bottom of the spinal cord which ends at L1/2 and the nerve roots. The back of this ring is made of the lamina and spinous processes to which several muscles are attached. For most of the lumbar spine, there is a group of nerve roots which trail down from the bottom of the spinal cord. The nerve roots, which are surrounded by spinal fluid and which are enclosed in a sac called the dura, are referred to as the cauda equina which translates to ‘horse’s tail’. At each level a nerve root exits the spine through a hole between each bone called the intervertebral foramen. That nerve root will supply feeling (sensation) to an area and will also supply muscles that perform different movements.

The disc is made of two main elements. The first is the annulus fibrosis. This is a strong outer layer made of criss-crossing fibres. The inside of the disc, or nucleus pulposus, is the soft gel-like centre which normally provides the cushioning functions of the disc.