VERTEBRAL COLUMN

VERTEBRAL COLUMN IN GENERAL

The vertebral column usually consists of 33 vertebrae: 24 presacral vertebrae

7 cervical12 thoracic5 lumbar

The 24 presacral vertebrae allow movement and hence render the vertebral column flexible. Stability is provided by ligaments, muscles, and the form of the bones. 

VERTEBRAL COLUMN IN GENERAL

followed by the sacrum5 fused sacral vertebrae

the coccyx4 frequently fused coccygeal vertebrae

CURVATURESThe adult vertebral column presents four anteroposterior curvatures: thoracic and sacral, both concave anteriorly (inwards) known as kyphosis, and cervical and lumbar, both concave posteriorly (outwards) known as lordosis

Spinal curves provide architectural strength and support the spine

Distribute vertical pressure on the spine

Balance the weight of the body If the spine were absolutely straight, it would be more likely to collapse under the pressure of the weight of the body

Between each of the two bones the space is supplemented by pads of fibro-cartilage called the

invertebral discs. The vertebrae are held together by ligaments which prevent their dislocation, but permit a degree of movement, making the backbone flexible.

Scoliosis is an abnormal curving of the spine. It runs straight down your back. People with scoliosis have a spine that curves too much. The spine might look like the letter “C” or “S.” exaggerated thoracic curvature

Kyphosis is a curving of the spine that causes a bowing or rounding of the back, which leads to a hunchback or slouching posture. The vertebral column is displace laterally.

PARTS/AREAS OF VERTEBRAE

VERTEBRAL BODY

The vertebral body is the main portion of the vertebra. It bears about 80% of the load while standing and provides an attachment for the discs between the vertebrae. The front or anterior section of the vertebral body protects the spinal cord and nerve roots. Both the vertebral body and the discs increase in size from the head to the sacrum.

LAMINA The lamina is is the roof of the spinal

canal that provides support and protection for the backside of the spinal cord

PEDICLES Each vertebra has two

cylinder-shaped projections (pedicles) of hard bone that stick out from the back part of the vertebral body, providing side protection for the spinal cord and nerves. The pedicles also serve as a bridge, joining the front and back parts of the vertebra.

SPINOUS PROCESSES

The bumps that can be felt down the back are the spinous processes. They are bony projections that arise at right angles (perpendicular) to the midline of the lamina. Each spinous process is attached to the spinous process above and below it by ligaments.

TRANSVERSE PROCESSES

The transverse processes are located at right angles to the junction of pedicles and the lamina. They provide a place for the back muscles to attach to the spine.

VERTEBRAL FORAMEN The vertebral foramen is

a bony tunnel surrounding the spinal cord. It is made up of the front (anterior) of the vertebral body, the pedicles on the sides of the vertebral body and the lamina in the back. In the lower back it not only contains the spinal cord, it also contains the nerve roots of the lower spine.

SUPERIOR ARTICULAR PROCESS

one on each side of the neural arch that projects upward and articulates with an inferior articular process of the next more cranial vertebra

TYPES OF VERTEBRAE

THE CERVICAL VERTEBRAE

Seven cervical vertebrae form the neck or cervical region.

The cervical vertebrae are the smallest of the bones

The first cervical vertebra is called atlas. It is almost ring like. It provides up and down or nodding movement to the skull on it.

The second cervical vertebra is termed as axis. Its centrum bears an odontoid process, which allows side to side or turning movement to the atlas and skull together on it.

CERVICAL VERTEBRAE The bodies of other cervical vertebrae

are small and oblong in shape broader from side to side than from backward.

The neural arch is large. The spinous processes are divided or bifid terminally.

The transverse processes are perforated by foramina for the passage of the vertebral arteries. Thus this important blood vessel is protected as it passes through the vulnerable region of the neck.

THORACIC VERTEBRAE These are 12 in number larger than the cervical vertebrae increase in size as they extend downwards. A typical thoracic vertebra has a heart-shaped

body with facets on each for attachment of the ribs.

The neural arch is relatively small the spinous process is long and is directed

downwards the transverse processes which help to

support the ribs are thick and strong and carry particular facets for the ribs.

LUMBAR VERTEBRAE These are 5 in number and are

located in the abdomen. These are the largest vertebrae

consisting of a very large body which are kidney shaped.

The spinous process is broad and hatchet-shaped.

The transverse processes are long and slender.

 SACRAL VERTEBRAE AND COCCYGEAL VERTEBRAE

These are 5 in number and are placed in the lower part of the vertebral column, forming the back of the pelvic cavity (sacral vertebrae)

These are 4 in number and occur in the vestigial tail. They are very small, rudimentary and fused to form a curved, triangular bone, the coccyx or tail bone. (coccygeal vertebrae)

BONY THORAX

Thoracic Cage made up of 24 bones

arranged in 12 pairs. These bones are divided

into three groups: true ribs, false ribs and floating ribs.

often called the "rib cage" because they form a kind of cage that encloses the upper body.

This cage gives the chest its familiar barrel-like shape

They protect the heart and lungs and major blood vessels in the chest. 

Ribs also protect parts of the stomach, spleen, and kidneys.

The ribs help you to breathe.

#’s 1&2. The organs protected by the thoracic cage include the lungs and the heart.

#’s 3-5

True ribs (vertebrosternal) – ribs 1 through 7 False ribs (vertebrochondral) – ribs 8 through 12 Floating - ribs 11 and 12

True ribs •The first seven bones

•These bones are connected to the spine (the backbone) in back. 

•In the front, the true ribs are connected directly to the sternum by a strips of cartilage called the costal cartilage. 

False ribs•They include ribs 8-12.

•no direct attachment to the sternum

•attached to the lowest true rib that provides connection to the sternum.

Ribs 8-10- have their cartilages attached to the costal cartilage of rib 7 (vertebrochondral):

Ribs 11-12 (floating ribs)

-attached posteriorly to the vertebrae-do not attach to cartilage and thus are considered “floating ribs”

#’s 6-7. All ribs articulate posteriorly with the thoracic vertebrae, and most connect anteriorly to the sternum, either directly or inderectly

POSTERIOR VIEW ANTERIOR VIEW

manubrium

body

Xiphoid process

sternum