vertebrae
-classification
unfused -cervical: 7 -thoracic: 12 -lumbar: 5 fused -sacral: 5 (fused as sacrum) -coccygeal: 4 (may be 3 or 5)
What 2 types of natural curvatures occur in the spine?
primary
secondary
primary curvatures
what -curvatures present embryologically -carried through during birth convex posteriorly -yield the curvature of the fetal position names -thoracic -sacral
secondary curvatures
what -curvatures that develop postnatally result of neuromuscular development necessary for -head support -bipedal locomotion types -cervical -lumbar
cervical curvature
convex anterior
develops to support the head
lumbar curvature
convex anterior
develops to support the body for bipedal locomotion
abnormal curvatures
-types
kyphosis
lordosis
scoliosis
kyphosis
what
-exaggerated posterior curvature
commonly seen in elderly with an exaggerated thoracic curvature giving the impression of a “humpback”
due to changes that occur during aging that result in
-bone loss
-loss of turgidity of the nucleus pulposus
can also be seen as a response to muscular changes following recovery from Poliomyelitis infection
lordosis
what
-exaggerated anterior curvature
commonly seen in women during pregnancy
-response to shifting of weight
scoliosis
what
-abnormal lateral curvature
result of…
-incomplete formation of vertebrae (hemivertebrae)
OR
-unequal muscle tension exerted on one side of the vertebral column
landmarks of a typical vertebrae (7)
body vertebral arch pedicles lamina spinous process transverse process articular processes (zygapophysis)
body
anterior aspect
size
-size increases inferiorly from cervical region through lumbar region
-size decreases from lumbar region through coccygeal region
roughened perimeter is a result of the attachment of the annulus fibrosus fibrocartilage of IV disc
smooth center
-composed of hyaline cartilage
-corresponds to position of nucleus pulposus
vertebral arch
encloses the vertebral foramen
vertebral canal
-canal formed by all vertebral foraminae collectively
formed by
-pedicles and laminae as they join via the transverse and spinous processes
pedicles
span distance between body and transverse processes
notches
-superior and inferior vertebral notches
purpose
-from the intervertebral foramen (spinal nerve passes through)
lamina
-span what distance?
span distance between transverse process and spinous process
spinous process
-projects…
projects posterior inferiorly
transverse process
project posterolaterally and slightly superiorly
act as leverage for the attachment of the intrinsic muscles of the back
-specifically the intermediate and deep or transversospinalis layers of muscles
articular processes (zygopophysis)
most commonly referred to as facet joints
composed of paired superior and inferior articular processes with an articular facet (face)
synovial planar joint
superior articular facet face
direction importance
-used an an identifying characteristic of each level of vertebrae
*face points perpendicular to plane of articular process
-i.e. face of lumbar superior articular process points inward; plane of process is in sagittal plane
cervical direction
-posterosuperior
thoracic direction
-posterior
lumbar direction
-medial
cervical vertebrae
-larger vertebral foramen (spinal canal) - more nerves (axons) coming out of these areas
-foramen transversarium for passage of vertebral artery (may be diminished in C7)
-bifid spinous processes (C1 only has a posterior arch)
vertebra prominens
-spinous process of C7
C1 and C2 characteristics
C1 -has no body, only an anterior ventral (posterior) arch C2 -has the odontoid process (dens) --formed from body of C1
important cervical ligaments
cruciform ligament
alar ligaments
thoracic vertebrae unique characteristics -costal facets --purpose --occur where --what type of facets are they and why? spinous process direction -purpose -rotation limited due to...
costal facets
-for articulation with ribs
where
-on side of vertebral body and transverse process of superior 10 ribs
-on pedicle for articulation with ribs 10-12
type
-demi- or hemifacets since articulation of head of the rib spans the intervertebral space
spinous processes are sloped posteroinferiorly
-restrict inferiorly
rotation limited due to true ribs
-more rotation in false and floating rib regions
lumbar vertebrae special characteristics (2)
massive bodies and lamina
no costal facets
L5 transverse process elongated for attachment of iliolumbar ligament
spina bifida occulta
-failure of closure of the posterior neuropore at L4
spinous processes point posteriorly