Vertebral Column Flashcards
Functions of the vertebral column
1)support weight 2)protect spinal cord 3)serve as axis and pivot 4)aid posture/movement
5 differentiated segments of vertebral column
-7 cervical -12 thoracic -5 lumbar -5 sacral -variable coccygeal vertebrae (typically 4)
Vertebral Body
Vertebral/Neural Arch
paired laminae & pedicles
-pedicles = join vertebral arch and body
laminae = flat plates contacting pedicles
vertebral foramne = forms vertebral canal
superior and inferior vertebral notches, form IV foramina
Vertebral processes
spinous process - 1 per vert
transverse - 2 per vert
articular process/zygapophysis - 4 per vert - 2 superior (pre-zygapophyses) and 2 inferior (post-zygapophyses)
Characterstics of Cervical Vertebrae
- transverse foramina - convey vertebral arteries
- anterior & posterior tubercles - on transverse processes
- carotid tubercle - anterior tubercle of C6
- vertebral foramina - large for C3-C7 because of cerbical enlargement of the cpinal cord
- uncinate process - raised margins of superior border of body
- C1/atlas
- articulates with occipital condyles
- lacks vertebral body
- groove for vertebral artery on superior surface
- C2/axis
- dens/odontoid process - former body of C1, and pivot for skull
- C7/vertebral prominens - long spinous process
Characteristics of Thoracic Vertebrae
costal facet, for rib hear
costal facet, for rib tubercle
spinous process - long and slender
Characteristics of lumbar vertebrae
- accessory process - posteriorly on each transverse process, attachment for intertransverse lumborum muscles
- mamillary process - attachments for multifidus and median intertrransverse muscles
- L5
- largest vertebrae in column
- huge contributor to lumbosacral angle
- lumbosacral angle = angle between lumbar and sacral vertebrae
Characteristics of Sacral Vertebrae
- sacral vertebrae fuse to form sacrum
- functions to transfer body weight to pelvis and contriubute to strenth and stability
- sacral canal - sacral continuation of vertebral canal
- sacral formina - between vertebrae
- sacral promontory - anterosuperior projecting ednge of S1
- median crest - fused spinous processes
- medial crest - fused articular processes
- lateral crest - fused transverse processes
- sacral hiatus - gap in laminae
- sacral cornua - former inferior articular processes of S5
- auricular surface - part of sacroiliac joint
Characteristics of Coccygeal Vertebrae
- rudimentary tailbone
- coccygeal conrua (horns) = part of Co1, articulate with sacral horns
Curvatures of the Vertebral Column
- Cervical - anteriorly convex, secondary
- Thoracic - anteriorly concave, primary
- Lumbar - anteriorly convex, secondary
- Sacral - anteriorly concave, primary
Types of curvatures
- Primary
- present at birth
- due to differences in A&P portions of vertebrae
- Secondary
- primarily developed after birth
- due to differences in A&P portions of IV discs
Movements of the Vertebral Column
- Movements:
- Flexion/extension
- lateral bending & rotation
- Restricted by:
- IV discs
- orientation of zygapophysial joints, articular capsules, muscles & ligatments
- range of motion results primarily from elasticity of IV discs
Clinical conditions of vertebral column
- Degenerative changes in vertebrae
- i.e. osteoporosis and osteoarthritis
- Abnormal curvature:
- i.e. kyphosis, lordosis, scoliosis
Vertebral Body Joints
- Secondary cartilaginous joints
- articulate via interposed IV discs
- IV discs
- Anulus fibrosis - outer portion of concentric fibrocartilaginous cicles
- nucleus pulposus - slightly posteriourly positioned gelatinous, elastic, avascular core
Uncovertebral joints
joints between uncinate process of C3-C6 and superjacent body
Vertebral arch joints (zygapophyses)
- synovial joints between superior and inferior articular processes
- allow gliding betwen vertebrae
- variable orientation limits movements
Longitudinal Ligaments
- Anterior longitudnal Ligament
- strong band extending across anterolateral vertebral bodies and IV discs
- prevents hyperextension of vertebral column, stabilizes vertebral body joints
- extends from sacrum to occiput & C1’s anterior tubercle
- Posterior longitudinal ligament
- weaker band extending along anterior aspect of vertebral canal
- prevents hyperflexion of vertebral column
- prevents herniation/protrusion of discs
Acessory Ligaments
- Ligamentum Flava
- Interspinous ligaments
- supraspinous ligaments
- Nuchal ligament/ligamentum nuchae
- Inter-transverse ligaments
Ligamentum Flavum (acessory)
- “yellow ligaments”
- connect adjacent laminae
- broad, yellow fibrous tissue extending along prosterior wall
- prevents abrupt flexion of vertebral column
Interspinous ligaments (accessory)
connect spinous processes
supraspinous ligaments (accessory)
connect tips of spinous processes
extends from C7 to sacrum
merges with ligamentum nuchae
nuchal ligament/ligamentum nuchae (accessory)
extends from external occiputal protuberance/posterior foramen magnum to spinous processes of cervical vertebrae
inter-transverse ligaments (accessory)
connects adjacenet transverse proceeses
obvious in thorax
Craniovertebral Joints
- atlanto-occipital joint
- atlanto-axial joint
Atlanto-occipital joint Movement
- primariliy allows nodding of head (flex/ext)
- allows lateral bending and rotation
atlantooccipital membranes
extend from atlas to margins of foramen magnum
prevents excessive movement
Cruciate Ligament
- Composed of:
- Transverse ligament of atlas
- holds dens of C2 with arch of C1
- posterior wall of dens’ socket
- Longitudinal bands
- extend from transverse ligament to occiput and C2 body
- Transverse ligament of atlas
Alar ligaments of atlanto-occipital joint
extend from sides of dens to C1 & foramen magnum
limits head rotation
tectorial membrane of atlanto-occipital joint
extends from C2 and through foramen magnum
suprior continuation of posterior longitudinal ligament
Atlant-axial Joint
- Joint between atlas & axis (2 lateral, 1 median)
- movement is primarily rotation
- C1 & skull rotate on C2, limited by alar ligaments
- C1/C2 zygapophysial joints = gliding joints
- dens & C11 articulation = pivot joint
Clinical conditions of Vertebral Joints & Ligaments
- Herniations and protrusions of nucleus pulposus
- Internal Decapitation
Spinal Arteries
- Branches of:
- vertebral & ascending cervical arteries - in neck
- posterior intercostal arteries - in thorax
- subcostal & lumbar arteries - in abdomen
- iliolumbar & lateral & medial sacral arteries - in pelvis
- Enter into IV foramina & divide into:
- terminal radicular arteries supplying ventral and dorsal roots
- medullary segmental arteries, which anastomose with spinal arteries
Spinal Veins
- Anterior & posterior components for each:
- internal venous plexus
- external venous plexus
Initial Vertebral Development
- involves sclerotomes, paired mesenchymal condensations around notochord
- part moves to form IV disc
- part forms mesenchymal centrum/futue vertebral body
- each centrum forms from 2 adjacent scelrotomes and becomes intersegmental
- notochord degenerates where surrounded by vertebral bodies
- notochord form nucleus pulposus between vertebral bodies
- the portion around neural tube forms neural arch
- mesenchymal cells in body wall from form ribs
Chondrificaiton
- Development of cartilaginous vertebral column
- Several chondrification centers:
- 2 fuse to form cartilaginous centrum
- 2 centers fuse to form neural arch, then arch fuses with body
- Neural arch centers also produce spinous and transverse processes
Ossification
- Development of bony vertebral column
- Primary ossification centers in each cartilaginous vertebrae:
- 2 fuse to form centrum
- 2 form vertebral arch
- Secondary ossification centers
- tip of spinous process ( 1 per vert)
- tip of transverse processes (2 per vert)
- annular epiphyses on superior and inferior rims of body (2 per vert)
Clinical Conditions of Spinal Development
Spina bifida
