Session 2, lecture 2.Lumbar Spine And Assosiated Disorders Flashcards
How many vertebrae are there in the vertebralcolumn ?
33
What makes up the vertebral column?
- 7 cervical vertebrae
- 12 thoracic vertebrae
- 5 lumbar vertebrae
- 5 sacral( fused)
- 4 coccygeal( fused)
What would the intervertebral disc called between the L3/L4 vertebrae?
The L3/L4 intervertebral disc
What parts of the vertebral column are mobile and which are immobile ?
1) the vertebrae in the cervical and lumbar spine are relatively mobile , whereas those in the thoracic spine are relatively less mobile as they are joined by the ribs to the sternum.
When does the lumbar spine begin ?
Just below the 12th rib
What are the functions of the lumbar spine ?
1) HAEMOPOIESIS the bone marrow of the vertebral column is an important site for haemopoiesis
2) PROTECT the spinal cord and the Cauda equina
3) SUPPORT : the thoracic spine and the Pelvis
4) MOVEMENT :highly flexible structure of bones. Intervertebral discs and ligaments allow this.
‘HPSM’
Structure of the lumbar vertebrae
Check notes
What is the largest part of the lumbar vertebra?
Anterior region
What type of cartilage covers the superior and inferior end plates of the anterior region of the lumbar vertebrae?
Hyaline cartilage
What is the anterior region of the lumbar vertebrae made up of - what type of bone ?
90% cancellous bone
- 10% cortical bone
What are the benefits of the anterior region of the lumbar vertebrae having a large amount of cancellous bone ?
1( lighter
2) allow for more haemopoiesis
3) MAIN REASON - helps to resist compression
Why does the size of the vertebral body ( anterior region) increase from superior to inferior ?
From L1 to L5 , the vertebral body increases in size because there is more weight the vertebrae has to hold.
How are adjacent vertebral bodies linked ?
By invertebraal discs
What is contained within the vertebral foramen ?
- conus medullaris
- cauda equina
- meninges
- epidural veins and spinal arteries
Describe the structure of the lumbar vertebra- posterior region
2 Pericles , 2 lamina + 7 processes
THE 7 processes :
1) 1 spinous process
2) 2 transverse process
3) 2 superior articular process
4) 2 inferior articular process
CHECK NOTES FOR IMAGE
What two structures does the pedicle connect ?
Connects the vertebral body and the transverse process
What two processes does the lamina connect ?
Connects the transverse process to the spinous process
What are the superior and inferior articular processes also referred to ?
The vertebral end plates
What are the superior and inferior articulR processes covered in?
Hyaline cartilage
How is the facet join created ?
Formed between adjacent superior and inferior articular processes.
What is the facet joint also referred to ?
Zygaphyseal joint
What type of joint is the facet joint ?
Synovial joint , lined with hyaline cartilage.
Between the facet joint , what is the hole called ?
Intervertebral foramen.
What does the intervertebral formamen allow the passage of ?
Spinal nerves
What to facet joints prevent the movement of ?
Prevents anterior displacement of vertebrae
What do the facet joints allow the movement of ?
Flexion and extension mainly.
What are the three main movements of the lumbar spine ?
1) flexion and extension
2) lateral flexion
3) rotation
What are the three types of joints in the lumbar spine ?
1) fibrous joints
2) secondary cartilaginous joints
3) synovial joints
What are the relative mobilities of the types of joints in the lumbar spine ?
1) fibrous joints - non-mobile
2) secondary cartilaginous : partially mobile
3) synovial joints : highly mobile
What is an example of synovial joints in the lumbar spine ?
Facet joints
What is an example of secondary cartilaginous joints in the lumbar spine ?
Intervertebral discs
What is an example of fibrous joints in the lumbar spine ?
Sacroiliac
What is the composition of intervertebral discs?
- 70% water
- 20% collagen
- 10% proteoglycans eg hyaluronic acid
Give an example of intervertebral discs change throughout the day
- in the morning we are a few mm taller than we are at the end of the day, this is because the intervertebral discs are well hydrated compared to at the end of the day.
What percentage of the length of the vertebral column do intervertebral discs account for ?
25%
What are the regions that within the intervertebral discs ?
1) nucleus pulposus which is central
2) annulus fibrosus which is peripheral
Describe features of the annulus fibrosus
- comprises lamellae of annular bands of collagen in varying orientations
- the outer lamellae are type 1 collagen and inner lamellae are fibrocartilganous
- it is avascular and aneural
- highly resilient under axial ( top to bottom) compression and is stronger than the vertebral body.
What is the remnant of the notochord?
Nucleus pulposus
What is the function of the annulus fibrosus
Major shock absorber
Describe features of the nucleus pulposus?
- gelatinous, type 2 collagen
- high oncotic pressure due to large amounts of water being stored in there
- centrally located in the infant , but located more posteriorally in the adult
Why is important to keep your spine straight whilst lifting heavy loads ?
Because intervertebral discs are very strong in axial compression ( top to bottom) but less strong under tangential loading ( load applied at an angle)
Describe the shape of the vertebrae in the fetus ?
- flexed in a single curvature
- c shaped
- this curvature is known as the primary curvature - consisting of one kyphosis.
In adult vertebral column , what are the two types of curves present ?
1) lordosis
2) kyphosis