5.3 - Vertebral Column and Back

axial skeleton

skull, vetrebal column and thoracic cage = 80 bones in total

appendicular skeleton

limbs including shoulder and pelvic girdles that attach to axial skeleton = 126 bones in total

sections of vertebral column

1. cervical - 7 vertebrate

2. thoracic - 12

3. lumbar - 5

4. sacrum - 5 fused

5. coccyx - 3-4 fused

when do vertebral curvatures develop

• primary curvatures - present at birth

• secondary curvatures - develop after birth

development of vertebral column curvate

• embryo = primary C curve

• adult = s-haped curve

primary curvature

• during fetal development

• C-shaped

• kyphotic

• thoracic and sacral

secondary curvature

• develop after birth

• lordotic

• cervical and lumbar

kyphotic

outward curve

• thoracic

• sacral

C shape

lordotic

inward curve

• cervical

• lumbar

how does cervical curvature develop

develops when baby lifts/holds head up

how does lumbar curvature develop

develops when baby stands and walks

atypical

not as common but natural variation

• usual vs unusual

abnormal

deviates from expected normal structure or function

• normal vs not normal

abnormal curvatures

• hyperkyphosis

• hyperlordosis

• scoliosis

hyperkyphosis

excessive outward curve

hyperlordosis

excessive inward curve

scoliosis

abnormal lateral (side-to-side) curvature when viewed from posterior

vertebra

any of the 33 individual small irregular bones forming spinal column

landmarks for typical vertebra

• vertebral body

• vertebral arch

• spinous and transverse proccesses

• articular processes

vertebral body

large anterior part of vertebrae

• for weight bearing

• connects superiorly and inferiorly

  • epiphyseal ring

what connects vertebral body to each other

symphysis - fibrocartilaginous joint allowing small movement

• vertebral body>symphysis> vertebral body

epiphyseal ring in vertebral body

ring of second ossification located on outer superior and inferior margins of vertebral body

• help with attachment of intervertebral discs

vertebral arch

posterior part of vertebrae surrounding vertebral foramen (hole) contains

• 2 pedicles

• 2 lamina

protects spinal cord

pedicles

connect verebral arch to vertebral body

lamina

extend posteriorly from pedicles and meet at spinous proccess

spinous process

1 per vertebrae - projects posteriorly from junction of 2 lamine

• levers for muscle and ligament attachment

• can feel thru skin

transverse processes

2 per vertebrae - project laterally from vertebral arch

• attachment for muscles and ligaments

articular processes

4 per vertabrae - projects from vertebral arch

• form articular facets

• 2 superior

• 2 inferior

articular facet

smooth flat surface covered in hyaline cartilage on articular process

• between adjacent vertebrae

• stabilise column

cervical vertebrae

• small rectangular body

• large triangular foramen

• spinal process splits into 2

• holes in tranverse processes

lumbar vertebrae

• large thick vertebral body

• triangular foramen

• long thin transverse processes

• superior articular facets face medially = toward each other

• inferior articular facets face laterally = away from each other

thoracic vertebrae

• heart shaped body

• small circular foramen

• long thin spinous process pointing inferiorly

• inferior articular process face anteriorly

• superior articular processes face posteriorly

sacrm vertebrae

triangular bone with 5 fused vertebrae and 4 pairs of foramina

vertebral foramen

opening within each vertebrae = contains and protects spinal cord

vertebral canal

continuous cannal by lining up vertebral foramina of all vertebrae

• from base of skull to sacral cannal

• protects spinal cord

vertebral notch

curved indentation (semi-circle) on superior and inferior borders of pedicle

• superior of 1 vertebrae and inferior of next form intervertebral foramen

intervertebral foramen boundaries

• superior - inferior vertebral notch from above vertebrae

• inferior - superior vertebral notch from below vertebrae

• anterior = vertebral body and interventricular disc

• posterior - facet joint and articular process

contents of intervertebral foramen

• spinal nerve roots

• dorsal root ganglia

• vessels

intervertebral joints

2 types

1. secondary cartilaginous joints

2. zygapophyseal (facet) joint -

secondary cartilaginous joints

between vertebral bodies connected by intervertebral disc

• hyaline cartilage end plate on superior and inferior surfaces between vertebral bodies

• body>hyaline>disc>hyaline>next body

intervertebral disc

disc contains

• annulus fibrosus = outer fibrocartilaginous ring

• nucleus pulposus inner gelatinuous core

annulus fibrosus

concentric lamellae of collagen

• attaches to epiphyseal ring

• keeps vertebra together

• permits movement in all directions

• resists excessive rotation

nucleus pulposus

• surrounded by annulus fibrosus

• keeps vertebra apart

• gelatinous = shock absorber = disperses compressive forces

• changes shape but not compressible

zygapophyseal joints

• plane synovial joint = sliding

• between superior articular process of 1 vertebrae and inferior articular of another

• movement depends on orientation of articular surfaces

plane of thoracic articular surfaces

coronal/frontal plane = superior faces posteriorly and inferior anteriorly

• relatively well rotation

plane of lumbar articular surfaces

sagittal plane = superior faces medially and inferior laterally

• flexion and extension with limited rotation

major vertebral column ligaments

• posterior and anterior longitudinal ligament

• ligamentum flavum

• interspinous and supraspinous ligament

posterior and anterior longitudinal ligament

• p = runs along posterior of vertebral bodies and discs - inside canal = limits flexion

• a = along anterior of vertebral bodies and discs = limits extension

interspinous and supraspinous ligaments

• I = between adjacent spinous processes = deep = limits flexion

• S - along tips of spinous processes = superficial = limits flexion

ligamentum flavum

plural = ligamenta flava

• connects laminae of adjacent vertebrae

• posterior wall of vertebral cannal

• limits flexion

• helps return to neutral position

extrinsic back muscles

connect vertebral column to upper limb

• trapezius

• rhomboid major and minor

• latissimus dorsi

• levator scapulae

trapezius

trapezoid shape spanning upper back, shoulders and neck

rhomboid minor and major

together parallelogram shape

• minor = superior = thinner

• major = inferior = larger

• deep/under trapezius

latissimus dorsi

large, broadest muscle covering most of lower back

levator scapulae

long narrow strap-like muscle in postolateral neck

• deep to trapezius

intrinsic back muscles

primarly attach to and act on back

• erector spinae - superficial

• transversospinalis - deep

erector spinae

prime movers of back particularly in sagittal plane (front and back movement)

• concentrically contract (shorten) to extend trunk (standing from touching toes)

• eccentrically contract (lengthen) trunk flexion e.g. slowly bending over

• common cause of pstural issues

trasversospinalis

group of short muscles

• deep to erector spinae

• control more fine movemets at vertebral segments