Back and Upper Extremity

• functions of the vertebral column

  axial skeleton

  protects the spinal cord and spinal nerves

  supports the weight of the body superior to the level of the pelvic

  plays role in posture and locomotion

  site of muscle attachment
• normal posture


  shoulder level, head erect

  BW slightly anterior

  abdomen retracted

  pelvic inclination = 60 degrees to line of gravity

  hips and knees are in extension
• whole-body center of gravity

  roughly around pelvis

  men usually higher up
• what affects posture?


  lifestyle
• anterior inclination of pelvis

  contraction of hip flexors and erector spinae

  more common
• posterior inclination of pelvis

  contraction of hip extensors and abdominal muscles
• curvature of the vertebral column

  cervical lordosis

  thoracic kyphosis

  lumbar lordosis

  sacral kyphosis
• vertebral column curvature development

  thoracic and sacral kyphosis develop in fetal period

  cervical and lumbar lordosis develop in infancy

  raising the head contributes to cervical lordosis development

  holding the body upright/walking develops lumbar lordosis
• excessive lordosis


  anterior pelvic tilt

  weak anterior abdominal muscles and hip extensors

  tight trunk extensors and hip flexors
• excessive kyphosis (hunchback)


  rounding of the shoulders

  weak upper back muscles

  tight pectoralis major

  wedge vertebrae: developmental/ due to compression fractures
• scoliosis (coronal/frontal plane)


  muscles on the outer part of the curve become weak

  muscles on the inner part of the curve tighten

  range from mild-severe

  typically arises in puberty

  mostly idiopathic

  more common in females

  Abdominal and thoracic cavity affected (thoracic cavity involvement: leading cause for surgical intervention)

  
  

  potential hemivertebrae
• atlas


  C1

  does not have spinous process
• axis C2


  has dens
• thoracic spine (T1-T12)


  body-heart shaped

  inferior, superior, and transverse costal facets

  
  

  flex/ext/lateral flexion; not rotation due to ribs
• lumbar spine L1-L5


  mammillary process (muscle attachment site)

  body is oval/bean shaped

  
  

  flex/ext/lateral flexion/ rotation
• pedicle is mostly injured in

  hyperextension
• if fractured (spondylolysis) the scottie dog looks like it has


  a collar
• sacrum and coccyx (S1-S5 C1-C4)


  sacral canal

  sacral hiatus (end of spinal cord)

  sacrococcygeal joint must still be mobile for childbirth
• Zygapophysical joints (Z-joints/Facet joints)

  C2-S1

  osteoarthritis can affect the facet joints causing impingement of the spinal n.
• intervertebral formina


  spinal n. exit
• intervertebral joints


  location of intervertebral discs (contain nucleus pulposus that is the site of a herniated disc; dries out around 40-50yrs old)

  symphyses= cartilaginous joints between adjacent vertebral bodies
• uncovertebral joints


  only found in cervical region

  small joints that sit on each side of the cervical disks

  not present at birth, develop with growth

  synovial, plane joint

  allow for flexibility, movement, and stability within the neck and limit sideways movement
• atlanto-occipital joint


  superior articular surface of C1 and occipital condyles

  flex/ext of the head "YES" joint + lateral flexion

  synovial, condyloid joint

  strengthened by anterior and posterior atlanto-occipital membrane
• atlanto-axial joint (C1->C2)


  3 articulations:

  •Right and left lateral atlanto-axial joint between inferior facets of C1 and superior facets of C2

  •Median atlanto-axial joint between the dens and anterior atlas

  
  

  • Axial - refers to C2, the axis

  • Median joint is a pivot joint

  • Lateral joints are gliding joints

  • Rotation of the head - the NO joint

  • Transverse ligament of the atlas and anterior arch forms a collar around the dens during pivot motion

  
  

  rotation
• what would occur is the transverse ligament of the atlas ruptures?

  head would translate anteriorly and disrupt the spinal cord

  transverse ligament of atlas = "collar" for the dens
• anterior longitudinal ligament


  anterior surface of vertebral bodies

  checks extension

  gets thicker in lumbar region
• posterior longitudinal ligament 


  posterior surface of vertebral bodies

  most anterior content of the vertebral canal

  tectorial membrane (C1-C2)
• ligamenta flava


  connect lamina of adjacent vertebrae (yellow)
• intertransverse ligaments


  connect adjacent transverse processes

  check lateral flexion
• interspinous ligaments

  connect adjoining spinous processes

  check flexion

  Continuations:

  supraspinous ligament (continuous from C7-sacrum)

  nuchal ligament (external occipital protuberance to foramen magnum and spinous processes of cervical vertebrae; C1-C7)
• vertebral canal boundaries

  Anterior: Posterior longitudinal ligament

  Posterior: Ligamentum flava and lamina

  Lateral: Intervertebral foramen

  Superior: Foramen magnum

  Inferior: Sacral hiatus
• layers of meninges of the spine

  dural sac/dura mater: exterior

  arachnoid mater: web-like

  pia mater: attached to the cord

  denticulate ligament: bilateral triangular lateral extensions of pia mater that anchor the spinal cord to the dura mater
• spinal cord

  white matter: axons

  grey matter: cell bodies

  posterior (dorsal)/ anterior (ventral) rootlets, root, ramus
• conus medullaris


  end of cord; shortens with age
• cervical/ lumbosacral enlargements

  for extremities/plexus' coming off
• filum terminale


  anchor cord
• lumbar cistern

  subarachnoid space in the lower lumbar spinal canal. An enlargement of the subarachnoid space in the dural sac, distal to the conus medullaris
• arterial supply to vertebrae

  spinal branches

  through the intervertebral foramen

  anterior vertebral canal a. OR posterior vertebral canal a.

  anastomose with adjacent branches
• cervical region venous return

  external vertebral venous plexus to dural venous sinuses (skull)
• thoracic region and below venous return

  external vertebral venous plexus to hemiazygos and azygos veins