Osteology of the Vertebral Column Flashcards
What are the 3 main functions of the vert column?
- Main Axial Support for body
- Protection
- Flexibility
How does the vert column provide main axial support for body?
- provides attachments for:
- skull
- thorax (articulates with ribs)
- pelvic girdle
How does the vert column provide protection?
- spinal cord sits within vert foramen
- openings between adj vert for passage of spinal nerves
How does the vert column provide flexibility?
- for trunk movements e.g. twisting, bending + carrying loads
What is the spine composed of and why is its arrangement an adv?
- series of bony segments connected by discs + lig.s linked by synovial + secondary cartilaginous joints
- only small displacements of multiple linkages is necessary for a large overall motion rather than a few highly mobile articulations which would be less stable and flexible.
What helps the spinal cord with movement?
- muscles
Why does vert column have curves?
- allows more stability + flexibility
What type of curve is the primary curve in the foetus and secondary curves in adult?
- primary curve - kyphotic
- secondary curves - lordotic
What are the secondary curves for in the adult and how do they change?
- cervical: holding head up
- lumbar: walking
- due to posture + weakening of muscles that support them with age
Name the parts of typical vert
- spinous process
- lamina
- pedicle
- vert foramen
- sup. + inf articular facets
- transverse process
- inf. + sup. notch
- body
- post. arch
Where are synovial joints located in a typical vert?
- sup. + inf. articular facets
- post. arch
What is function of inf. + sup. notch?
- where spinal nerves come through when they form a foramen
How is the vert canal formed and what is its function?
- when put vert on top of each other
- where spinal cord, meninges + vessels come through
What is function of vert body?
- supporting longitudinal loads
- takes up to 75% of forces going through vert
What is the int. structure of the vert body and why is it like that?
- outer shell of cortical bone
- trabeculated internal structure horizontal + vertical - organised to resist stress and therefore add resilience to the structure
+ prevent compression from the side - channels between the trabeculae are filled with blood which assists in absorbing the load.
What are the functions of the lamina?
- protects contents of vert column
- Transmission of force from the articular processes to the body.
- takes 25% of forces going through vert
Where is the lamina thickest and why?
between the superior and inferior facets and this also helps to withstand bending forces.
What happens during osteoporosis?
- trabeculae gets thinner
- more force goes through lamina
What is the structure + function of articular process?
- Paired superior and inferior processes bearing synovial joints.
- permit a limited amount of movement and, as the orientation of the joints changes throughout the column, the range of movement in each region varies.
How do the shape of art facets differ in diff vert?
- cervical:
- flat
- vertically orientated (allows you to pivot head)
- thoracic:
- flat + vert joints - restricts bending but can get rotation
- lumbar:
- curvatures which limit rotation
What are pedicles and what is their function?
- The connection between the posterior elements and the body of the vertebra.
- take forces at the joint + from muscle attached to transverse + spinous processes + transmit it onto body - therefore helping to resist unwanted movements and these stout pillars resist bending in any direction.
- The bodies are designed for weight bearing and therefore cannot resist twisting or sliding forces.
What are the functions of the spinous and transverse processes?
provide areas for muscle attachment
Name the 5 regions of the vert column and how many vert they have
Cervical - 7 Thoracic - 12 Lumbar - 5 Sacrum - 5 Coccyx - 2-4
What are the features of cervical vertebrae?
- 2 foramina in transverse process for vert artery to supply post. aspect of brain + artery behind
- facets become more vert as go down which helps stability
- large foramen to allow entry of brachial plexus
- bifida in spinous process (C3-C6)
- uncovert joints in CS-C7 give movement and stability
What is function of neurocentral articulation of cervical vert?
can provide another area of attachment in younger people
What is function of ant. + post. tubercle of cervical vert?
for muscle attachment
What is unique about C1 + C2?
- no body, art facet instead or spine
- C1 has facet for dens which fits into C2
- articulates with occipital condyles
- C2 has dens which allows pivot movement
What is unique about C7?
- Long spinous sprocess = vert prominens
- no bifid
What is sig about down pos of C2?
- restricted movement between C2 + C3 compared to C1
What is the transverse lig. and its’ function?
- attaches to lat. mass/tubercles across C1
- ensures integrity of joint - prevents dens slipping back into spinal cord
What is found between the occipital condyles and lat. mass of C1?
- V. strong synovial joint with strong capsules
Where is the weight of the head transmitted?
- through occipital condyles to lat. mass of atlas
- all forces go through synovial joint and then weight transmitted to to bodies of cervical vert
Where is location and what is function of art on thoracic vert?
- art on TP + 2 on body on both sides
- where ribs art
What happens to art of thoracic vert from T10?
- shifts to middle of body
How does the shape of thoracic vert change?
- cup shaped in upper (affects movements of ribs during resp) + flat shaped in lower
- 1 + 2 backward facing
- 3 + 4 downward facing
- 5 to 8 has downward kissing spines and so not much movement
- 11 + 12 backward facing
Where do ribs art?
- through demi facets (1/2 joints)
Describe the shape of lumbar vert
- L1 + L1 oval shaped and more rounded
- gets more triangular as you get lower
Where does spinal cord end what changes?
- between L1 + L2
- then you get horse’s tail where spinal nerves exit and why shape changes
What is unique about lumbar vert?
- no transverse foramina
- no rib art
What does sacrum art with?
hip bone
What is function of ant. pelvic sacral foramina?
nerves come here to supply lower limb
What is function of interosseous sacroiliac lig.?
keeps sacrum in place
What type of joint is sacroiliac joint and what is its function?
- synovial but little movement as its meant to be stress relief joint
- prevents vert column slipping out of the pelvis
