The Spine Flashcards
How many small bones are in the vertebral column?
33 small bones (vertebrae) which are separated by intervertebral discs.
What are the four functions of the spine?
- Protection - encloses and portects the spinal cord within the spinal canal.
- Support - carries the weight of the bodu above the pelvis.
- Axis - forms the central axis of the body.
- Movement - has roles in both posture and movement.
What are the five regions of the spine?
- Cerivical (7)
- Thoracic (12)
- Lumbar (5)
- Sacrum (5, fused)
- Coccyx (4, fused)
What is the structure of a vertebrae?
They each consist of a vertebral body, situated anteriorly, and a posterior vertebral arch.
What is the structure of the vetebral body?
The vertebral body is the anterior part of the vertebrae. It is the weight-bearing component, and its size increases as the vertebral column descends (having to support increasing amounts of weight).
The superior and inferior aspects of the vertebral body are lined with hyaline cartilage. Adjacent vertebral bodies are separated by a fibrocartilginous intervertebral disc.
What is the vertebral arch?
The vertebral arch refers to the lateral and posterior parts of the vertebrae.
What is the vertebral foramen?
With the vertebral body, the vertebral arch forms an enclosed hole, called a vertebral foramen.
What is the vertebral canal?
The foramina of the all vertebrae line up to form the vertebral canal, which encloses the spinal cord.
What are the bony prominences of the vertebral arches?
The vertebral arches have a number of bony prominences, which act as attachment sites for muscles and ligaments:
Pedicles: There are two of these, one left and one right. They point posteriorly, meeting the flatter laminae.
Lamina: The bone between the transverse and spinous processes.
Transverse processes: These extend laterally and posteriorly away from the pedicles. In the thoracic vertebrae, the transverse processes articulate with the ribs.
Articular processes: At the junction of the lamina and the pedicles, superior and inferior processes arise. These articulate with the articular processes of the vertebrae above and below.
Spinous processes: Posterior and inferior projection of bone, a site of attachment for muscles and ligaments.
What are the distinguishing features of the seven cervical vertebrae?
The spinous process bifurcates into two parts, and so is known as a bifid spinous process.
There are two transverse foramina, one in each transverse process. These conduct the vertebral arteries.
The vertebral foramen is triangular in shape
What are the C1 and C2 vertebrae called and what are they specialised for?
C1 and C2 called the atlas and axis respectively, are specialised to allow for the movement of the head.
What is the main function of the thoracic vertebrae?
Their main function is to articulate with ribs, producing the bony thorax.
What is the structure of the thoracic vertebrae?
Each thoracic vertebrae has two ‘demi facets‘ on each side of its vertebral body. These articulate with the head of the respective rib, and the rib inferior to it. On the transverse processes of the thoracic vertebrae there is a costal facet for articulation with its respective rib.
The spinous processes are slanted inferiorly and anteriorly. This offers increased protection to the spinal cord, preventing an object like a knife entering the spinal canal through the intervertebral discs.
In contrast to the cervical vertebrae, the vertebral foramen is circular.
What is the structure and function of the lumbar vertebrae?
These are the largest of the vertebrae, of which there are five. They act to support the weight of the upper body, and have various specialisations to enable them do this.
Lumbar vertebrae have very large vertebral bodies, which are kidney-shaped. They lack the characteristic features of other vertebrae, with no transverse foramina, costal facets, or bifid spinous processes.
However, like the cervical vertebral, they have a triangular shaped vertebral foramen.
What is the structue of the sacrum and coccyx?
The sacrum is a collection of five fused vertebrae. It is described as an upside down triangle, with the apex pointing inferiorly. On the lateral walls of the sacrum are facets, for articulation with the pelvis at the sacro-iliac joints.
The coccyx is a small bone, which articulates with the apex of the sacrum. It is recognised by its lack of vertebral arches. Due to the lack of vertebral arches, there is no vertebral canal, and so the coccyx does not transmit the spinal cord.
