Day 5 Boney Landmarks and Structure of the Vertebral Column KH 2220 Laura Abbott, MS, LMT Day 5 Boney Landmarks and Structure of the Vertebral Column

Spinal Column The vertebral column is often called the “spinal column” or the “spine”. In adults, it consists of 26 bones. The top 24 bones are called vertebrae and the bottom two are called the sacrum and coccyx. Running through the center of the vertebral column is the spinal canal, which contains the spinal cord. Nerves emerge from the spinal cord and exit between the vertebrae.

5 Sections of Vertebral Column cervical (neck) section: top 7 vertebrae (C1-C7) thoracic (upper back) section: 12 vertebrae (T1-T12) lumbar (lower back) section: 5 vertebrae (L1-L5) sacrum: 5 fused bones coccyx: 3-5 fused bone

Normal Curves of the Spine Lordotic Kyphotic

Abnormal Curves of the Spine Lordosis

Abnormal Curves of the Spine Kyphosis

Abnormal Curves of the Spine Scoliosis

The Typical Vertebra The vertebral body is the large rounded portion that forms the anterior part of the vertebra. The vertebral foramen is the large hole posterior to the body. When all the vertebrae are in their proper position, their vertebral foramina form a continuous tube- the spinal canal. The pedicles and the laminae form the walls of the vertebral foramen.

The Typical Vertebra The transverse processes are lateral projections on the vertebra. The spinous process is a projection on the posterior part of the vertebra. The superior articular processes are two projections on the superior surface of the vertebra. Each one has a flattened surface called a facet.

The Typical Vertebra The inferior articular processes: two projections on the inferior surface of the vertebra. Each of these also has a flattened surface called a facet. The picture below shows how the superior articular processes of one vertebra meet the inferior articular processed of the overlying vertebra to form a joint. Intervertebral foramen: a hole, which is formed by the meeting of two vertebrae. Spinal nerves exit the spine through the intervertebral foramen. It is at this point that spinal nerves can be impinged upon, resulting in severe pain or

Cervical Vertebra Cervical vertebras have small bodies and large vertebral foramina. The transverse processes of each vertebra have a transverse foramen. The transverse foramina provide passage for the vertebral artery, which supplies the brain.

C1-The Atlas The two unique structural features of the atlas are: it has no body it has no spinous process Other points of interest: The vertebral foramen is huge because it has to provide passage for the spinal cord which, at this level is also huge. The transverse processes are very prominent and may be palpated just inferior to the mastoid process The atlas has 2 massive superior articular processes whose bowl-shaped facets accommodate the condyles of the occipital bone. This joint enables the occipital bone to rock back and forth on the atlas, thus allowing us to nod our heads “yes”

C2- The Axis The second cervical vertebra, or axis, from above is also unique. Its spinous process is quite massive. The key feature of C2 is the odontoid process an upward projection, which fits, into C1. The joint between C2 and C1 allows us to shake our heads “No”.

Thoracic Vertebrae have long slender spinous processes, which are oriented sharply downward. have flattened surfaces on the transverse processes and bodies for attachment of the ribs. These surfaces are called facets on the transverse processes and demifacets on the bodies. Due to the attachment of the ribs to the thoracic vertebrae, the thoracic section is not as freely moveable as the cervical section.

Lumbar Vertebrae Whereas the cervical vertebrae are highly mobile, the lumbar vertebrae are built for strength. They have large bodies and massive spinous processes that are oriented straight back

The Sacrum In adults, the sacrum consists of 5 fused bones, which are designated as S1-S5. Between the fused segments are sacral foramina on the anterior and posterior surfaces of the sacrum. At birth, the 5 sacral segments are not fused. They remain as 5 separate bones until about the age of 20.

The Coccyx The coccyx consists of 3-5 fused bones. It is considered to be the vestige of a tail. In fact, babies are often born with a small tail, which projects down from the tip of the coccyx.

Discs The intervertebral disc is situated between adjacent vertebral bodies. It consists of an outer ring of fibrocartilage called the annulus fibrosis, and a soft gelatinous interior called the nucleus pulposus.

The Herniated Disc The term “slipped disc” is a misnomer It is possible to have a bulging disc, wherein the annulus fibrosis is overstretched and the nucleus pulposus balloons out. Even more serious is a ruptured disc, wherein the annulus fibrosis is torn, and the nucleus pulposus escapes. A bulging or ruptured disc may be called a HERNIATED disc. A herniated disc can press upon a spinal nerve root or even the spinal cord, causing severe pain

The Disc has 2 functions It firmly joins the bodies of adjacent vertebrae The soft nucleus pulposus makes the disc an effective cushion that protects the vertebral bodies from too much compression.

Ligaments of the Spine The anterior longitudinal ligament is a broad flat ligament that runs along the anterior surface of the vertebral bodies. It links the bodies together and fuses with the discs. Its function is to prevent excessive extension of the vertebral column.

Ligaments of the Spine The posterior longitudinal ligament runs along the back of the vertebral bodies. It is thinner and more delicate than the anterior longitudinal ligament. Its function is to prevent excessive flexion.

Ligaments of the Spine The nuchal ligament runs from the EOP (external occipital protuberance) to the spinous process of C7.

Ligaments of the Spine The supraspinous ligament is a thin stringy ligament that joins the tips of the spinous processes.

Ligaments of the Spine The interspinous ligaments are situated between the spinous processes of adjacent vertebrae. Numerous muscles help to hold the vertebrae together.

Spondylolysis “Stress fractures” of the spine Low back pain Not always a definitive cause. Some people develop it with no history of back injury, others may have it and have no pain.

Spondylolisthesis Slippage of vertebrae –usually L5-S1 Pain that worsens with spinal flexion and relieved with spinal extension Causes: traumatic injury, degeneration, and rarely, pathological (tumor leading to lesions)

Stenosis Abnormal narrowing of the spinal canal Most common in cervical and lumbar regions Caused by degeneration, less commonly by tumors Symptoms – pain, numbness, weakness – the shopping cart leaners