Vertebral column Flashcards
What’s within the vertebral column cavity
Spinal cord
Roots of spinal nerves
Meninges
How many vertebrae are there and what are they classified into
33 vertebrae: 7 cervical 12 thoracic 5 lumbar 5 sacral 4 coccygeal
How many vertebrae are discrete and how many are fused
What structures do the fused vertebra form
24 discrete
9 fused - forms sacrum and coccyx
Gross functions of vertical column
Project body weight to pelvis and lower limbs
Attachment for bones and muscles
Protection and passage of spinal cord
Segmental Innervation of spinal cord (spinal nerves leave/join at specific points)
Shock absorption
How does the vertebral column project body weight to pelvis and lower limbs
What is the direction of transmission
Vertebral bodies increase in size inferiorly
Sacral vertebrae are fused, widened and concave anteriorly (transmits weight through pelvis)
Through line that passes centrally through curvatures of VC (centre of gravity)
What bones attach to the VC
Skull
Ribs
Iliac
What muscles attach to the VC
Muscles of trunk (maintain erect posture and move VC)
Muscles of pelvic and pectoral girdles
Typical structure of vertebrae
Anteriorly - rounded body
Posteriorly - vertebral arch
Vertebral foramen
Features of body of vertebrae
Usually largest part
Main weight bearing part
Major site of contact between adjacent vertebrae
Articular surface is covered with hyaline
Features of vertebral arch of vertebrae
1 spinous process 2 transverse processes 2 superior articular processes/facets 2 inferior articular processes/facets Formed by lamina and pedicle
What does the lamina connect
Transverse process to spinous process
What does the pedicle connect
Transverse process to vertebral body
What’s formed between articular processes of adjacent vertebrae
Synovial joints
What strengthens synovial joints between adjacent vertebrae
Ligamentum flavum
Where do spinal nerves emerge
Intervertebral foramina
What type of joint does the articulation of superior and inferior articular processes form
Facet joint (synovial)
How is anterior displacement of vertebrae prevented
Superior and inferior articular processes interlock
What type of joints are intervertebral discs
Cartilaginous symphysis joints
What percentage of VC length is intervertebral discs
25%
How are intervertebral discs kept turgid
High water content
What happens to intervertebral discs with age
Dehydrate and get smaller
What feature of intervertebral discs allows for secondary curvature of spine
Wedge shaped
2 regions of intervertebral discs
Central - nucleus pulposus
Peripheral - annulus fibrosus
What structures does the vertebral column support
Skull
Pectoral girdle
Upper limbs
Thoracic cage
How does the position and size of the nucleus pulposus change with age
Central in infants but more posterior in adults
Shrinks with age (and over day due to compression by gravity)
What’s the nucleus pulposus a remnant of
Notochord
Features of nucleus pulposus
Gelatinous
High osmotic pressure
Blood and neural supply of annulus fibrosus
None
Structure of annulus fibrosus
Lamellae of annular bands in varying orientations that entirely surround the nucleus pulposus
Difference between outer and inner lamellae in annulus fibrosus
Outer - collagenous
Inner - fibrocartilaginous
Function of annulus fibrosus
Major shock absorber Resists compression (stronger than vertebral bodies)
Stages of disc herniation
Disc degeneration
Prolapse
Extrusion
Sequestration
Where does disc herniation most commonly occur
L4/L5
L5/S1
Describe disc degeneration
Chemical changes associated with aging causes disc to weaken
Describe prolapse
Protrusion of nucleus pulposus with slight impingement into spinal canal
Describe extrusion
Nucleus pulposus breaks through annulus fibrosus but remains within disc space
Describe sequestration
Nucleus pulposus breaks through annulus fibrosus and lies outside disc space in spinal canal
What direction do discs usually herniate
What is the consequence
Posterolaterally
Compression of spinal nerve roots
What happens when discs herniate posteriorly
May cause spinal cord compression (neurological emergency)
Effects of disc degeneration
Increased stress on discs
Increased stress on facet joints
Decreased size of vertebral foramina
Effect of increased stress on discs with disc degeneration
Spondylosis deformans (growth of osteophytes around degenerating IV discs)
Effect of increased stress on facet joints with disc degeneration
Osteoarthritis
pain as facet joints are innervated by meningeal branch of spinal nerve
Effect of decreased size of intervertebral foramina with disc degeneration
Compression of spinal nerves e.g cervical spondylosis
What is cervical spondylosis
Degenerative osteoarthritis of intervertebral joints in cervical spine causing the cervical vertebrae to stiffen (neck pain)
This puts pressure on nerve roots (radiculopathy) and spinal cord (myelopathy)
Effect of pressure on nerve roots in cervical spondylosis
Paraesthesia
Pain
Myotomal motor weakness
Effect of pressure on spinal cord in cervical spondylosis
Global weakness
Gait dysfunction
Loss of balance
Loss of bladder and bowel control
