Vertebral Column

• Characteristics of the Vertebral Column


  the vertebral column consists of 26 irregular bones connected in such a way that a flexible, curved structure = result

  the spine extends from the skull to the pelvis, where it transmits the weight of the trunk to the lower limbs

  it also surrounds + protects the delicate spinal cord + provides attachment points for the ribs + for the muscles of back + neck
• 5 Major Vertebral Regions


  7 vertebrae of the neck = cervical vertebrae

  next 12 = thoracic verterbrae

  5 supporting lower back = lumbar vertebrae

  common meal times - 7am, 12, 5pm

  inferior to the lumbar vertebrae = sacrum which articulates w the hip bones

  the terminus of the column = coccyx

  
• Curvatures of the Spine


  4 curvatures of the spine, when seen from the side that give it its S shape

  cervical + lumbar curvatures r concave posteriorly

  thoracic + sacral r convex posteriorly

  these curvatures increase the resilience + flexibility of the spine, allowing it to function like a spring
• Intervertebral Discs - Structure


  each intervertebral disc = cushion-like pad composed of 2 parts:

  inner gelatinous nucleus pulposus, acting like a rubber ball + giving the disc its elasticity + compressibility

  surrounding the nucleus pulposus = strong collar composed of collagen fibres superficially + fibrocartilage internally = anulus fibrosus

  = limits the expansion of the nuclues pulposus when the spine is compressed
• Intervertebral Discs - Functions


  sandwiched between the bodies of neighbouring vertebrae, intervertebral discs act as shock absorbers during walking, jumping + running

  allow the spine to flex + extend + to a lesser extent to bend laterally

  the discs r thickest in lumbar + cervical regions, enchancing the flexibility of these regions

  
• General Structure of Vertebrae - Vertebral Body, Arch, Foramen & Canal


  all vertebrae have a common structural pattern

  each vertebra consists of a body, anteriorly, + vertebral arch posteriorly

  together the body + vertebral arch enclose an opening = vertebral foramen

  successive vertebral foramina form the long vertebral canal, thru which the spinal cord passes

  
• Vertebral Arch - Pedicles


  the vertebral arch = a composite structure formed by 2 pedicles + 2 laminae

  the pedicles = short bony pillars projecting posteriorly from the vertebral body, forming the sides of the arch

  
• Vertebral Arch - Laminae


  laminae = flattened plates that fuse in the median plane, complete the arch posteriorly
• Vertebral Arch - Pedicles & Intervertebral Foramina


  the pedicles have notches on their superior + inferior borders, providing lateral openings between adjacent vertebrae = intervertebral foramina

  the spinal nerves from the spinal cord pass thru these foramina
• 7 Processes of the Vertebral Arch - Spinous Process


  the spinous process = median posterior projection arising at the junction of the 2 laminae

  
• 7 Processes of the Vertebral Arch - Transverse Process


  a transverse process extends laterally from each side of the vertebral arch

  the spinous + transverse processes r attachment sites for muscles that move the vertebral column + for ligaments that stabilise it

  
• 7 Processes of the Vertebral Arch - Paired Superior & Inferior Articular Processes


  the paired superior + inferior articular processes protrude superiorly + inferiorly, respectively, from the pedicle-lamina junctions
• Facets & Movable Joints


  the smooth joint surfaces of the articular processes = facets r covered w hyaline cartilage

  the inferior articular processes of each vertebra form movable joints w the superior articular processes of the vertebra immediately below

  thus successive vertebrae join both ath their bodies + at their articular processes
• Regional Vertebral Characteristics


  beyond their common structural features, vertebrae exhibit variations that allow diff regions of the spine to perform slightly diff functions + movements
• Movements Occuring Between Vertebrae

  flexion + extension (anterior bending + posterior straightening of the spine)

  lateral flexion - bending the upper body L + R

  rotation - vertebrae rotate on one another in the longitudinal axis of the spine