Vertebral column Flashcards
list of vertebrae
33 total 7 cervical 12 thoracic 5 lumbar 5 sacral 4 coccygeal
lumbosacral angle
junction of lumbar region of vertebral column and sacrum
significant motion occurs between only
superior 25 vertebrae
intervertebral disks
make presacral vertebral column flexible
fibrocartilage
zygapophysial joints
25 cervical, thoracic, lumbar and first sacral vertebrae articulate at these synovial joints which facilitate and control flexibility
curvatures of vertebral columns
primary: thoracic and sacral: kyphoses
secondary: cervical and lumbar: lordoses
osteoporosis
net demineralization of bones and results from disruption of normal balance of calcium deposition and reorption
vertebral body osteoporosis most common in thoracic
excessive thoracic kyphosis
humpback
erosion of anterior part of one or more vertebrae
dowager hump: when in women
excessive lumbar lordosis
hollow back anterior rotation of pelvis, increase in lumbar curvature abnormal extension deformity weakened trunk musculature pregnancy
scoliosis
curved back
abnormal lateral curvature accompanied by rotation of vetebrae
spinous processes turn toward cavity of abnormal curvature
most common deformity of vertebral column in pubertal girls
difference in length of lower limbs, hemivertebra and myopathic scoliosis are causes
hemivertebra
failure of half of a vertebra to develop
myopathic scoliosis
asymmetric weakness of intrinsic back muscles
sacral curvature of females
reduced so that coccyx protrudes less into pelvic outlet
lumbar curvature in females
more pronounced
vertebral body
anterior, massive part
gives strength to column and supports body weight
superior and inferiorly covered by hyaline cartilage
epiphysial rim
ring of smooth bone at periphery of vertebral body
vertebral arch
posterior to vertebral body and formed by right and left pedicles and laminae
pedicles
short, stout processes that join bertebral arch to vertebral body
laminae
broad, flat plates of bone which unite in the midline
vertebral foramen
formed by vertebral body and vertebral arch
vertebral canal
succession of vertebral foramina in articulated column
contains spinal cord, meninges, fat, spinal nerve roots and vessels
vertebral notches
indentations formed by projection of body and articular processes superior and inferior to pedicles
IV foramina
superior and inferior vertebral notches of adjacent vertebrae combine
give passage to spinal nerve roots and accompanying vessels and contain spinal ganglia
spinous process
projects posteriorly and usually inferiorly from vertebral arch at junction of laminae
transverse processes
2 project posterolaterally from junctions of pedicles and laminae
articular processes
2 superior, 2 inferior, arise from junctions of pedicles and laminae, each bearing articular facet
cervical vertebrae body
small and wider from side to side than anteroposteriorly
superior surface is concave between uncinate (adjacent) processes. inferior surface is convex
cervical vertebral foramen
large and triangular
cervical transverse processes
foramina transversaria
small or absent in C7
vertebral arteries and accompanying venous and sympathetic plexuses pass through foramina (except C7)
anterior and posterior tubercles
cervical articular processes
superior facets directed superoposteriorly, inferior facets direct inferoanterioly
cervical spinous process
C3-C5: short and bifid
C6 is long
C7 is longer
C7 aka
vertebral prominence
C1 distinctive characteristics
atlas
ring like, somewhat kidney shaped when viewed superior or inferiorly
no spinous process or body
consists of 2 lateral masses, connected by ant and post arches
concave superior articular facets for atlantooccipital joints with occipital condyle
flat inferior facets meet with C2 vertebrae to form lateral atlantoaxial joints
C2 distinctive characteristics
Axis
strongest cervical vertebrae
distinguishing feature is dens, which projects superiorly from body and provides pivot
articulates anteriorly with anterior arch of atlas and posteriorly with transverse ligament of atlas
thoracic body
heart shaped
one or 2 bilateral costal facets for articulation with head of rib
thoracic vertebral foramen
circular and smaller than cervical and lumbar
thoracic transverse process
long and strong
extends posterolaterally
length diminshes from T1 to T12
T1-T10 have transverse costal facets for tubercle of rib
thoracic articular processes
superior articular facets directed posteriorly and slightly laterally
inferior articular facets directed anteriorly and slightly medially
thoracic spinous process
long, slopes postero inferiorly, overlapping subadjacent vertebral body
lumbar body
massive
kidney shaped
large and heavier
lumbar vertebral foramen
triangular
larger than thoracic, smaller than cervical
lumbar transverse process
long and slender, accessory process on posterior surface of base of each process
lumbar articular processes
superior articular facets directed posteromedially or medially
inferior articular facets directed anterolaterally (or laterally)
mammillary process on posterior surface of each superior articular process
lumbar spinous process
short and sturdy
hatchet shaped
base of sacrum
superior surface of S1 vrtebrae
sacral promontory
projecting anterior edge of body of first sacral vertebra
median sacral crest
fused spinous processes
interneduate sacral crests
fused articular processes
lateral sacral crests
fused tips of transverse processes
sacral hiatus
inverted and u shaped
results from absence of laminae and spinous processes of S4 S5
leads to sacral canal
sacral cornua
representing inferior articular processes of S5 project inferiorly on each side of sacral hiatus
laminectomy
surgical excision of one or more spinous processes and supporting laminae
provide access to vertebral canal to relieve pressure in spinal cord or nerve roots
fractures of vertebrae
usually from sudden flezxion
compression fracture usually of body
also dislocation and fracture of articulating facets
spina bifida occulata
most common congenital anomaly of vertebral column
laminae of L5 and or S1 fail to develop normally and fuse
24% of people
no back problems
tuft of hair
spina bifida cystica
one or more vertebral arches may almost completely fail to devekio
herniation of meinges and or spinal cord
meningocele
herniation of meninges
meningomyelocele
herniation of spinal cord
whiplash
severe hyperextension of neck
anterior longitudinal ligament severely stretched and may be torn
spondylolysis
fractures of interartucular parts of vertebral laminae (L5)
spondylolisthesis
forward displacement of L5 vertebral body relative to sacrum
may result in pressure on spinal nerves of causa equina causing back and lower limb pain
lumbar spinal stenosis
narrow vertebral formane in one or more lumbar vertebrae
treatment of decompressive laminectomy
foramina transversaria of cervical vertebrae
vertebral arteries
posterior median furrow
horizontal line joining highest points of iliac crests passes through tip of L4 spinous process and L4-L5 spinous disk
S2 spinous process
middle of line drawn between posterior superior iliac spines, indicated by skin dimples
sacral triangle
lines joining posterior superior iliac spines and superior part of intergluteal cleft
common area of pain
joints of vertebral bodies
symphyses (secondary cartilaginous joints)
IV discs
articulating surfaces of adjacent vertebrae connected.
provide strong attachments between the vertebral bodies
shock absorbers
permit movement between adjacent vertebrae
IV discs consist of
anulus fibrosus
nucleus pulposus
anulus fibrosus
outer fibrous part
ring consisting of concentric lamellae of fibrocartilage forming the circumference of the IV disc
anuli insert into the smooth, rounded epiphysial rims on articular surfaces of vertebral bodies
fibers forming each lamella run obliquely from one vertebra to another
nucleus pulposus
central core of IV disc
at birth, 85% water
pulpy nuclei become broader when compressed thinner when tensed or stresed.
dehydrate with age and lose elastin and proteoglycans while gaining collagen
thinner and stiffer
not centered in the disc but more posteriorly placed
avascular
most inferior functional IV disc
between L5 and S1
thickness of IV discs
thicker in cervical and lumbar regions
thinnest in superior thoracic region
thickness most uniform in thoracic region
Uncovertebral “joints” of Luschka
between uncus of the bodies of C3-C6 and the beveled inferolateral surfaces of vertebral bodies superior to them
lateral and posterolateral margins of IV discs
articulating surfaces covered with cartilage and contain a capsule filled with fluid
frequent sites of spur formation
anterior longitudinal ligament
strong fibrous band that covers and connects the anterolateral aspects of vertebral bodies and IV discs
extends from pelvic surface of sacrum to anterior tubercle of C1 vertebra and the occipital bone anterior to the foramen magnum
maintains stability of the IV joints and limits extension of the vertebral column
posterior longitudinal ligament
weaker band compared to anterior longitudinal ligament
runs within vertebral canal along posterior aspect of vertebral bodies
attached mainly to the IV discs and less so to the posterior edges of the vertebral bodies from C2 to the sacrum
helps prevent hyperflexion of the vertebral column and posterior herniation of the IV discs
well innervated with pain nerve endings
zygapophysial joints
facet joints
synovial plane joints between the superior and inferior articular processes of adjacent vertebra
surrounded by thin, loose, articular capsule, attached to margins of articular surfaces of articular processes of adjacent vertebrae.
accessory ligaments unite transverse and spinous processes and help stabilize the joints
permit gliding movements between articular processes
innervated y articular branches that arise from medial branches of posterior rami ofspinal nerves. each joint supplied by 2 adjacent spinal nerves
ligamenta flava
laminae of adjacent vertebral arches are joined by broad, pale, yellow elastic fibrous tissue which extend almost vertically from the lamina above to the lamina below
bind the laminae of adjoining vertebrae together
resist separation of the vertebral laminae by arresting abrupt flexion of the vertebral column and thereby preventing injury to the IV discs
help preserve posture and assist with straightening the column after flexing
interspinous ligaments
weak, almost membranous ligaments that unite adjacent spinous processes
suprspinous ligaments
strong fibrous ligaments that attach adjacent spinous processes
nuchal ligament
strong median ligament of the neck
composed of thickened fibroelastic tissue extending from EOP and posterior border of foramen magnum to spinous processes of cervical vertebrae
craniovertebral joints
atlanto-occipital
atlanto-axial
synovial joints with no IV discs
atlanto occipital joints
between C1 and occipital condyles
permit nodding of head
mainly flexion, little lateral flexion, some rotation, permit sideways tilting og head
condyloid, synovial joints
anterior and posterior atlanto occipital membranes
extend from anterior and posterior arches of C1 to the anterior and posterior margins of the foramen magnum
help prevent excessive movement of joint
Atlanto Axial joint types
Two lateral atlanto-axial joints (right and left) between the lateral masses of C1 and superior facets of C2, plane type synovial joint
and one median atlanto axial joint between the dens of C2 and the anterior arch and transverse ligament of the atlas. pivot joint
movement of atlanto axial joint
no movement
cranium and c1 vertebra rotate on C2 vertebra as a unit. dens of C2 is the pivot
transverse ligament of atlas
strong band extending between tubercles on medial aspects of the lateral masses of C1 vertebrae
longitudinal bands
vertically oriented but much weaker superior and inferior. pass from transverse ligament to occipital bone superiorly and to the body of C2 inferiorly
Cruciate ligament
transverse ligament and longitudinal bands form it
alar ligaments
stout, extend from sides of dens to lateral margins of foramen magnum
attach cranium toC2 vertebra and serve as check ligaments, preventing excessive rotation
tectorial membrane
strong superior continuation of posterior longitudinal ligament across median atlanto-axial joint through foramen magnum to central floor of cranial cavity
body of C2 to the internal surface of occipital bone and covers the alar ligaments and transverse ligaments of atlas
blood supply of vertebrae
periosteal and equatorial branches of major cervical and segmental arteries
spinal branches of vertebral and ascending cervical arteries in neck, posterior intercostal arteries in thoracic, subcostal and lumbar arteries in abdomen, iliolumbar and lateral and medial sacral arteries in pelvis
periosteal and equatorial branches arise from above arteries as they cross external surfaces of vertebrae
spinal branches enter IV foramina and divide into anterior and posterior vertebral canal branches that pass to vertebral body and vertebral arch respectively
give rise to ascending and descending branches that anastamose with spinal canal branches of adjacent levels. spinal branches continue as terminal radicular arteries distributed to posterior and anterior roots of spinal nerves and coverings or as segmental medullary arteries that continue to spinal cord
venous supply
spinal veins form venous plexuses inside (internal vertebral epidural venous plexus) and outside (externnal vertebral venous plexus) the vertebral canal. basivertebral veins form within vertebral bodies and emerge from foramina on surfaces of vertebral bodies and drain into internal and external vertebral venous plexuses. intervertebral veins receive veins from spinal cord and vertebral venous plexuses as they accompany spinal nerves through IV foramina to drain into vertebral veins of neck and segmental veins of trunk
other than zygapophysial joints, vertebral column innervation
meningeal branches of spinal nerves
some branches remain outside canal: branches ouside supply anuli fibrosi and anterior longitudinal ligament
recurrent branches supply periosteum, ligamenta flava, anuli fibrosi posteriorly, posterior longitudinal ligament, spinal dura mater, and blood vessels within the vertebral canal
herniation of nucleus pulposus
herniation into or through anulus fibrosus: causes lower back and limb pain
degeneration of posterior longitudinal ligament and wearing of analus fibrosus allows herniation which compresses spinal cord or nerve roots of spinal nerves in cauda equina
usually posterolaterally
herniation most common in lumbar region\
sciatica
rupture of transverse ligament of atlas
dens is set free, resulting in atlanto-axial subluxation or incomplete dislocation of median atlanto axial joint. with complete dislocation, dens may be driven into upper cervical region of spinal cord: quadriplegia or the medulla: death
rupture of alar ligaments
combined flexion and rotation of the head
results in an increas of approx 30% in range of moement to opposite side
aging of vertebrae and intervertebral discs
overall decrease in bone density and strength
nuclei pulposi become stiffer
lamellae of anulus thicken and develop fissures and cavities
IV discs increase in diameter and covexity
increase in compressive forces at periphery of vertebral bodies
injury and disease of zygapophysial joints
related spinal nerves are affected
causes pain along dermatomes and spasm in the muscles derived from associated myotomes
denervation of lumbar zygapophysial joints is procedure for treatment
types of back pain causes
- fibroskeletal structures: periosteum, ligaments and anulu fibrosi of IV discs
- meninges: coverings of spinal cord
- synovial joints: capsules of zygapophysial joints
- muscles: intrinsic muscles of back
- Nervous tissue: spinal nerves or nerve roots exiting IV foramina
