Vertebral Column

Question 1

Gross features of the vertebral column

Answer 1

Forms central axis of the skeleton
~70-75cm long
33 vertebrae
Highly flexible and strong

Question 2

Functions of vertebral column

Answer 2

Provides for centre of gravity
Attachments for bones and trunk muscles
Passage of spinal cord, protection of spinal cord
Segmental innervation of the body
Acts as a conduit through which an assembly nerve fibres pass- efferents and afferents

Question 3

What is kyphosis

Answer 3

An abnormality of the spine causing excessive curvature of upper back, this causes pain and stiffness
May be caused by poor posture during childhood or be result of abnormally shaped vertebrae or developmental problems with the spine

Question 4

Primary curvature

Answer 4

Retained from original Fetal curvature
The thoracic and sacral curves are primary curvatures

Question 5

Vertebral column in young adult

Answer 5

Has 4 distinct curvatures, stretched S shape
Sinusoidal profile, sinous bends give the column great flexibility and resilience
2 anterior and posterior flexion (concavities)
The anterior concavities are continuations of the primary curvature of foetus
Posterior concavities are secondary curvatures in response to development
The cervical spine develops the 1st posterior concavity when a young child begins to lift its head, secondary curvature
Lumbar spine also opens up during crawling until child walks- second posterior concavity

Question 6

Normal curvatures of the vertebral column

Answer 6

Cervical (secondary)
Thoracic (primary)
Lumbar (secondary)
Sacral (primary)

Question 7

Important vertebral levels curvature of spine

Answer 7

Centre of gravity crosses sinous bends at vertebral levels
C1&C2
C7&T1
T12&L1
L5&S1
These points happen to constitute sites of natural weak points of vertebral column these sites of vertebral column are potential sites for disc herniations

Question 8

Vertebral column in old age

Answer 8

Secondary curvatures start to disappear
Continuous primary curvature re-establishes

Question 9

Fused vertebrae

Answer 9

Sacrum- fusion 5 sacral vertebrae
Coccyx- fusion 4 coccygeal vertebrae

Question 10

Atypical discrete vertebrae

Answer 10

Atlas CI-articulates with head
Axis CII- pivot upon the atlas
Atlas lacks a vertebral body
No intervertebral disc between them

Question 11

Typical vertebrae

Answer 11

Consists of a vertebral body and a posterior vertebral arch which forms lateral and posterior parts of vertebral foramen

Question 12

Vertebral body

Answer 12

Usually largest part
Main weight bearing part
Linked to adjacent vertebral bodies by intervertebral discs and ligaments
Size of body increase inferiorly as amount of weight supported increases

Question 13

Vertebral arch

Answer 13

Forms lateral and posterior parts of vertebral foramen
Consists of pedicles and laminae
A spinous process projects posteriorly and inferiorly from junction of 2 laminae and is a site for muscle and ligament attachment
A transverse process extends posterolaterally from junction of pedicle and lamina on each side, is a site for muscle and ligament attachment and for articulation of ribs in thoracic region

Question 14

Pedicle

Answer 14

Bony pillars that attach the vertebral arch to the vertebral body
Between the vertebral/neural arch and transverse process

Question 15

Lamina

Answer 15

Flat sheets of bone that extend from each pedicle to meet in midline and from riff of vertebral arch
Between transverse process and spinous process

Question 16

Superior and inferior articular processes

Answer 16

Projecting from region where pedicles join the laminae
Which articulate with the inferior and superior articular processes respectively of adjacent vertebra

Question 17

Superior and inferior vertebral notches

Answer 17

Between the vertebral body and the origin of the articular processes each pedicle is notched on its superior and inferior surfaces
Participate in forming the intervertebral foramina

Question 18

Intervertebral disc

Answer 18

Fibrocartilaginous cushions between vertebrae that allow movement, support and act as shock absorbers
Has an outer fibrous ring- the annulus fibrosus
A central region- nucleus pulposus
Has a high water content that keeps it turgid and forms it bulk
May shrink in size with age

Question 19

The annulus fibrosus

Answer 19

Made from a series of annular bands in varying orientations
Outer bands are collagenous
Inner bands are fibrocartilaginous
Very resilient
Surrounds the nucleus pulposus
Shock absorber

Question 20

Nucleus pulposus

Answer 20

Jelly like
High osmotic pressure
Acts as water reservoir for disc
Changes in size throughout day depending on water distribution within disc
Can herniate through annulus fibrosus if there’s degeneration- slipped disc: occurs most commonly posterolaterally, results in compression of spinal segmental nerves (painful), posterior herniation may compress the spinal cord (leading to complete paralysis)

Question 21

Ossification of typical vertebrae

Answer 21

Begin ossification in embryonic period of development around 8 weeks gestation
Vertebrae ossify by endochondral route
Ossify from:
3 primary ossification centres- first to start ossifying
5 secondary ossification centres

Question 22

3 primary ossification centres

Answer 22

One in endochondral centrum (which will develop into vertebral body)
One in each neural process (which will develop into the pedicles)
Ossification begins at thoracolumbar junction and proceeds in both cranial and caudal directions

Question 23

Secondary ossification centres

Answer 23

The neural processes fuse with the centrum in between 3&6 years age
During puberty 5 secondary ossification centres develop:
At the tip of spinous process
Both transverse processes
And on superior and inferior surfaces of vertebral body
Ossification centres on the vertebral body are responsible for the superior-inferior growth of vertebrae
Ossification ends around age 25