S2) Vertebral Column Flashcards
What is the vertebral column?
The vertebral column is a vertical series of approx. 33 small vertebrae bones, which are separated by intervertebral discs
What are the five main functions of the vertebral column?
- Support: carries the weight of the body above the pelvis
- Haemopoiesis: red bone marrow production
- Axis: forms the central axis of the body
- Movement: highly flexible structure
- Protection: encloses and protects the spinal cord and the cauda equina within the spinal canal
Identify the sections of the vertebral column as well as the number of vertebrae found in each
All vertebrae share a basic common structure.
Describe it
- Consists of an anterior vertebral body
- Consists of a posterior vertebral arch
Describe the structure, function and location of the vertebral body
- Structure: hyaline cartilage lines superior and inferior aspects
- Function: weight-bearing component (size increases as the vertebral column descends)
- Location: anterior part of the vertebrae
What separates adjacent vertebral bodies?
Adjacent vertebral bodies are separated by a fibrocartilaginous intervertebral disc (annulus fibrosis)
What is the vertebral foramen and why is it significant?
- The vertebral foramen is an enclosed hole formed by the vertebral body and the vertebral arch
- The foramina of the all vertebrae line up to form the vertebral canal, which encloses the spinal cord
Identify the 5 different bony prominences on a typical vertebrae
Identify the 3 distinguishing characteristics of the cervical vertebrae
- Bifid spinous processes (except C7)
- Transverse foramina (conduct the vertebral arteries)
- Triangular vertebral foramen
Identify the 4 distinguishing characteristics of the thoracic vertebrae
- Two ‘demi facets‘ on each side of the vertebral body (articulate with head of the respective rib, and inferior rib)
- Costal facets on transverse processes (articulation with respective rib)
- Spinous processes are slanted anteroinferiorly
- Circular vertebral foramen
Identify 2 distinguishing characteristics of the lumbar vertebrae
- Large kidney-shaped vertebral bodies
- Triangular vertebral foramen
Identify 2 distinguishing characteristics of the sacral vertebrae
- Five fused vertebrae
- Facets on lateral walls (articulation with the pelvis at the sacro-iliac joints)
Identify 3 distinguishing characteristics of the coccyx vertebrae
- Fused vertebral bodies
- No vertebral arches
- No vertebral canal (does not transmit the spinal cord)
Identify and describe the major joints of the vertebral column
- Fibrocartilaginous joints: between vertebral bodies (indirectly)
- Facet joints: between inferior and superior articular processes
- Costovertebral joints: between head of rib and thoracic vertebral body
- Costotransverse joints: between tubercle of rib and thoracic transverse process
Identify the two ligaments that strengthen the vertebral fibrocartilaginous joints and describe their function
- The anterior longitudinal ligament is thick and prevents hyperextension of the vertebral column
- The posterior longitudinal ligament is weaker and prevents hyperflexion of the vertebral column
Identify the four ligaments which strengthen the facet joints in the vertebral column
- Ligamentum flavum
- Interspinous ligaments
- Supraspinous ligaments
- Inter transverse ligaments
Describe the structure and location of the ligamentum flavum
- Structure: yellow in colour, composed of elastic fibres
- Location: extends from lamina to lamina of adjacent vertebrae
Describe the structure and location of the interspinous ligaments
- Structure: relatively weak sheets of fibrous tissue, fused with supraspinous ligaments
- Location: extends between spinous processes of adjacent vertebrae
Describe the structure and location of the supraspinous ligaments
- Structure: strong bands of white fibrous tissue
- Location: extend between tips of adjacent spinous processes
Describe the structure and location of the inter transverse ligaments
- Structure: blend with intertransverse muscles
- Location: extends between transverse processes
Describe the structure and function of the intervertebral discs
- Structure: consists of nucleus pulposus (central) and annulus fibrosus (peripheral)
- Function: account for 25% of the length of the vertebral column
Describe the composition of the intervertebral discs
- 70% Water
- 20% Collagen
- 10% Proteoglycans
Describe the structure, function and location of the annulus fibrosis
- Structure: outer lamellae of Type 1 collagen and fibrocartilaginous inner lamellae, avascular and aneural
- Function: major ‘shock absorber’
- Location: surrounds nucleus pulposus
Describe the structure and location of the nucleus pulposus
- Structure: remnant of notochord, gelatinous, Type 2 collagen
- Location: surrounded entirely by annulus fibrosus
A slipped disc is a herniation commonly occurring at L4/5 and L5/S1.
Identify the four different types
- Disc degeneration: aging causes disc to dehydrate and bulge
- Prolapse: protrusion of the nucleus pulposus with slight impingement into the spinal canal (contained)
- Extrusion: nucleus pulposus breaks through annulus fibrosus (undisplaced)
- Sequestration: nucleus pulposus breaks through annulus fibrosus and separates from the main body of the disc (displaced)
What are the types of disc prolapse?
- Lateral disc protrusion usually compresses the nerve root above (5%)
- Paracentral disc protrusion usually compresses the nerve root below (95%)
In a paracentral herniation of the L4/5 disc, why is the L5 root is most frequently compressed?
The L5 root is compressed as the L4 root emerges above the level of the L4/5 disc (but below the L4 vertebrae)
What is sciatica?
Sciatica is the compression of the nerve roots which contribute to the sciatic nerve
Identify the different types of sciatica and the parts of the limb affected
- L4 Sciatica – anterior thigh, anterior knee, medial shin
- L5 Sciatica – lateral thigh, lateral calf, dorsum of foot
- S1 Sciatica – posterior thigh, posterior calf, heel, sole of foot
What is Cauda Equina Syndrome?
Cauda equina syndrome is a serious condition that comes with extreme pressure and swelling of the nerves at the end of the spinal cord
Identify 5 red flag signs/symptoms of cauda equina syndrome
- Bilateral sciatica
- Perianal numbness
- Painless retention of urine
- Urinary / faecal incontinence
- Erectile dysfunction
What is lumbar spinal stenosis?
- Lumbar spinal stenosis (LSS) is a clinical condition in which the spinal canal narrows and compresses the spinal cord and nerves at the level of the lumbar vertebrae
- It is caused by ageing, spinal disc herniation, osteoporosis or a tumour
What is neurogenic claudication?
Neurogenic claudication is a common symptom of lumbar spinal stenosis or inflammation of the spinal nerves involving pain in the legs during motion
In 5 steps, describe the pathophysiology of neurogenic claudication
⇒ Venous engorgement and arthritis causes osteophyte formation
⇒ Spinal canal narrows
⇒ Blood supply to nerve is limited
⇒ Nerve roots become ischaemic
⇒ Pain occurs during motion
What is spondylolisthesis?
Spondylolisthesis is a slip forwards of the vertebrae above on the vertebra below due to a fracture in the pars interarticularis
What are the different types of spondylolisthesis?
- Dysplastic (abnormality in facet joint shape)
- Isthmic (pars interarticularis defect)
- Degenerative
- Iatrogenic
- Pathological
Which part of the vertebrae is known as pars interarticularis?
Pars interarticularis is located between the superior and inferior articular process of the facet joint
Distinguish between the following terms:
- Spondylosis
- Spondylitis
- Spondylolysis
- Spondylolisthesis
- Spondylosis: age-related wear and tear to bones of the spine
- Spondylitis: inflammation of the joints of the spine
- Spondylolysis: fractures in pars interarticularis
- Spondylolisthesis: movement of one vertebrae relative to the ones above/below it
Describe the structure of the foetal vertebral column
The vertebral column is flexed in a single C-shaped curvature (primary curvature) which is concave anteriorly (kyphosis)
Where is the primary curvature maintained in adult life?
- Thoracic region
- Sacral region
- Coccygeal region
Describe the structure of the vertebral column in the young adult
4 distinct curvatures:
- Kyphoses (anterior flexions): thoracic and sacrococcygeal
- Lordoses (posterior flexions): cervical and lumbar
Describe the development of the secondary curvatures
- Cervical lordosis appears when young child begins to lift its head
- Lumbar lordosis develops when child begins to standup and walk
Senile kyphosis develops in old age.
What is this?
Senile kyphosis – secondary curvatures start to disappear and the continuous primary curvature is re-established
Describe the structure of the vertebral column during pregnancy
Exaggeration of lumbar lordosis
What are the weak points of vertebral column (centre of gravity)?
- C1 & C2
- C7 & T1
- T12 & L1
- L5 & S1
