Vertebral Column Flashcards
Gross features of the vertebral column
Forms central axis of the skeleton
~70-75cm long
33 vertebrae
Highly flexible and strong
Functions of vertebral column
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
What is kyphosis
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
Primary curvature
Retained from original Fetal curvature
The thoracic and sacral curves are primary curvatures
Vertebral column in young adult
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
Normal curvatures of the vertebral column
Cervical (secondary)
Thoracic (primary)
Lumbar (secondary)
Sacral (primary)
Important vertebral levels curvature of spine
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
Vertebral column in old age
Secondary curvatures start to disappear
Continuous primary curvature re-establishes
Fused vertebrae
Sacrum- fusion 5 sacral vertebrae
Coccyx- fusion 4 coccygeal vertebrae
Atypical discrete vertebrae
Atlas CI-articulates with head
Axis CII- pivot upon the atlas
Atlas lacks a vertebral body
No intervertebral disc between them
Typical vertebrae
Consists of a vertebral body and a posterior vertebral arch which forms lateral and posterior parts of vertebral foramen
Vertebral body
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
Vertebral arch
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
Pedicle
Bony pillars that attach the vertebral arch to the vertebral body
Between the vertebral/neural arch and transverse process
Lamina
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
Superior and inferior articular processes
Projecting from region where pedicles join the laminae
Which articulate with the inferior and superior articular processes respectively of adjacent vertebra
Superior and inferior vertebral notches
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
Intervertebral disc
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
The annulus fibrosus
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
Nucleus pulposus
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)
Ossification of typical vertebrae
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
3 primary ossification centres
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
Secondary ossification centres
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
