Joints & Movements of the Vertebral Column #1 Flashcards
List the 4 types of vert column motility
- Flexion
- Rotation
- Lat. flexion
- Extension
Which vert column region has less flexion + extension?
flexion
List the degrees of lat. flexion of each vert column region
- lumbar: 20
- thoracic: 20
- cervical: 35
How does the structure lumbar region of vert column affect its movement?
- synovial joints limit rotation due to curved AF
How does the structure of thoracic region of vert column affect its movement?
get more rotation due to vert + flat art
How does the structure of cervical region of vert column affect its movement?
pivot joint between C1 + C2 - get more rotation
What is forward flexion?
bending forwards flexes lumbar spine
What is forward flexion + axial rotation?
bending forwards + upper body rotated at same time
What is lat. flexion?
lat. bending prod asymm bending common in manual handling
Which pos of spine is the most unstable and why?
- lat. flexion
- ass with disc prolapse + back pain
What determines mobility of vert column?
- movements poss between art. joints on laminae
- shape + orientation of joints dictates direction + range of movements poss between adj vert
What type of joint is the facet joint?
- synovial
- has 2 art surfaces covered with hyaline cartilage enclosed by synovial mem + joint capsule
What extra art do thoracic vert have?
for ribs
What does intervert disc allow?
synovial joints to move
What is the problem if vert were to just rest on top of each other?
give adequate joint for weight bearing + allow gliding but flatness of vert would not allow rocking movements ass with flexion + extension
What is the solution to the issue of having vert resting on top of each other?
- interpose bodies with layer of strong but deformable tissue with 3 major requirements:
1. strong enough to sustain weight i.e. transfer load from 1 vert to next without collapsing
2. deformable to accomm rocking movements of vert without compromising strength
3. strong enough not to be injured during movement
Why can’t the surface of vert be flat?
no movement
Why can’t surface of vert be curved?
forces would only be going through 1 point due to limited contact
What are the 3 components of intevert disc?
- Nucleus Pulposis
- Annulus Fibrosis
- Vert End Plate
What does the structure of intervert disc allow?
- all forces transmitted from 1 vert to other in neutral pos
- can deform + large SA means can transmit forces
What is function of vert end plate?
- sep bone from rest of disc + covers area where nucleus is
- form perm barrier between nucleus + bone through which water + nutrients may pass
- prevent nucleus bulging into vert body
Why is there movement of fluid from disc to bone?
provide nutrients for disc + movement of materials between the 2
What type of joints are intervert joints?
secondary cartilaginous
What are the collagen fibres in the annulus like + why?
- have degrees/angles of rotation
- rings not always complete
- allows slow deformation so invert discs act as shock absorber when forces transmitted between vert so don’t feel it during movement
What happens when forced put on disc?
- nucleus start to deform + flatten slowly
- bulging of annulus
- vert end plate stops it pushing up into bone
What is the env of the disc like at rest?
equ between amount of fluid in the system + forces acting on it
What happens to synovial joints during extension?
closer together and so more stable
What happens to synovial joints during flexion
further apart + least stable pos as not so packed together
Describe what a grade 2 intervert disc is like
- nucleus appears fibrous + contains some brown pigment
- not degen
Describe what a grade 3 intervert disc is like
- mod degen changes
- annulus bulging into nucleus
- end plate damage
Describe what a grade 4 intervert disc is like
- severe degen
- disruption to both end plates
- disc red in height
- pigmented
- bits of intervert disc beginning to bulge into vert body
What is consequence of loss of height of intevert disc?
- loss of height in vert foramen puts pressure on peripheral nerves as they’re leaving
- leads to sciatica, + degen in neck + lumbar region
What is the consistency of the nucleus pulposis + why?
- toothpaste
- 70% water in adult
What is the histology of nucleus pulposis?
few cartilage cells + type 1 collagen fibres
What does the fluid nature of the pulp allow?
- can be deformed but vol can’t be compressed
- when weight applied, red in height + exerts P on annulus
What is structure of annulus fibrosis?
- highly ordered lamellae (10-20) of collagen type I
- thicker ant. + more tightly packed post.
Why is structure of annulus important?
lattice construction gives disc its strength + ability to resist deformation from nuclear P + load from vert body
What is structure of the end plates and where are they found?
- hyaline cartilage
- surround nucleus pulposis
