Lumbar Spine Flashcards
How many vertebrae are in the spine? What are the areas?
33 vertebrae
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 4 coccygeal
Are all parts of the spine capable of movement?
- 24 separable vertebrae
- All capable of individual movement
- Mobile = cervical and lumber
- Relatively immobile = thoracic
- 9 vertebrae fused to give to innominate structures in sacrum and coccyx
What are the functions of the vertebral column?
- Central bony pillar of the body
- Supports the skull, pelvis, upper limbs and thoracic cage
- Protection of the spinal cord and the cords equina
- Movement = highly flexible structure of the bones, intervertebral discs and ligaments
- Haemopoiesis - red marrow
How do the vertebral bodies change in size according to placement in the spinal column?
Vertebral bodies increase in size inferiorly as compression forces increase
How are the sacral vertebrae structured to support weight bearing?
Sacral vertebrae are fused, widened and concave anteriorly to transmit weight of the body through pelvis to legs.
What are the movements of the lumbar spine?
Flexion and extension
Lateral flexion
Rotation
Describe the general structure of a typical lumbar vertebra
- Kidney shaped vertebral body
- Vertebral arch posteriorly
- Vertebral foramen: for spinal cord and meninges
Describe the processes that stem from the vertebral arch
- 1 spinous process posteriorly
- 2 transverse process
- 2 superior articular process
- 2 inferior articular process
Describe the key features of the vertebral bodies
- Usually the largest part of the vertebra
- Usually main weight bearing part of the vertebra
- Major site of contact between adjacent vertebrae
- End plates = articular surfaces covered with hyaline cartilage
- Linked to adjacent vertebral bodies by intervertebral discs
- Size increases from superior to inferior
How do the vertebral processes of the vertebrae interlock with other vertebra?
- 2 superior articular processes (facets) interlock with the vertebra above
- 2 inferior articular processes interlock with the vertebra below
What is the lamina?
Connects transverse process to spinous process
What does the pedicle do?
Connects the transverse process to the body
What makes up the vertebral arch?
Lamina and pedicle
What forms synovial joints between vertebrae?
Vertebral arches of adjacent vertebrae
Where do spinal nerves emerge from?
Intervertebral foramina
What is a synovial facet joint?
Articulation of superior and inferior articular processes
What is the function of the interlocking design of the facet joints of the vertebrae?
- Interlocking design prevents anterior displacement of vertebrae
- Orientation determines the amount of flexion and rotation permitted.
Why do intervertebral discs lose height with age?
Because repair of proteoglycans is less good as we age.
What accounts for the secondary curvature of the spine?
Slightly wedge shaped discs which are wider posteriorly.
What are the two regions of the intervertebral disc?
- Nucleus pulposus (central)
- Annulus fibrosus (peripheral)
What makes up the annulus fibrosus?
- Made from the lamellae of annular bands in varying orientations
- Inner lamellae are fibrocartilaginous
- Outer lamellae are fibrocartilaginous
- Avascular and aneural
What is the function of the annulus fibrosus?
- Major ‘shock absorber’
- Highly resilient under compression - stronger than the vertebral body
What is the nucleus pulposus?
- Remnant of the notochord
- Gelatinous (Type 2 Collagen)
- High osmotic pressure
- Changes in size throughout the day/ with age
- Surrounded by annulus fibrosis
- Centrally located in the infant, more poster in the adult
What is the function of the ligaments in the vertebral column?
Provide stability (anterior stronger than posterior_
What are the major ligaments of the vertebral column?
Anterior longitudinal and posterior longitudinal
Describe the key features of the anterior longitudinal ligament
- Anterior tubercle of atlas to sacrum
- United with periosteum of vertebral bodies
- Mobile over intervertebral discs
- Prevents hyperextension
Describe the key features of the posterior longitudinal ligament
- Body of the axis to sacral canal
- Relatively weak
- Prevents hyperflexion
- Position dictates where disc prolapse - as tears occur at the lateral margin of the posterior ligament
What is the ligamentum flavum?
- Yellow in colour due to elastic fibres
- Between laminae of adjacent vertebrae
- Stretched during flexion of the spine
What are the interspinous ligaments?
- Relatively weak sheets of fibrous tissue
- Unite spinous processes along adjacent borders
- Well developed only in the lumbar region (stability in flexion)
- Fuse with supraspinous ligaments
What are the supraspinous ligaments?
- Tips of adjacent spinous processes
- Strong bands of white fibrous tissue
- Lax in extension
- Tight in flexion (mechanical support for vertebral column)
Describe the articulations of the sacrum
- L5 superiorly
- Ilium laterally
- Coccyx inferiorly
Describe the curvatures of the vertebral column
Lordosis = curves backwards Kyphosis = curves forwards Cervical = L Thoracic = K Lumbar = L Sacral = K Coccyx = K = Sinusoidal profile
Describe the shape of the vertebral column in the foetus
- Flexed in a single curvature
- C-shaped
- Concave anteriorly (Kyphosis)
= Primary curvature
When does the cervical lordosis develop?
When a child begins to lift its head
When is the lumbar lordosis developed?
When the child begins to stand up and walk
