Lect 4: Spine Osteology

A/F Lecture 1

What components make up the axial skeleton?

• cranium

• vertebral column

• sternum

• ribs

the vertebral column is composed of

vertebrae and deformable discs

vertebral column function (4)

provide riggid but flexible axis for movement

firm base for suspendin structures (let body maintain relative posture)

link upper/lower extremities

protect spinal cord

What are te 5 regions of the vertebral column?

• cervical (7)

• thoracic (12)

• Lumbar (5)

• sacrum (5 fused)

• Coccyx (4 fused)

How many vertebrae are in eac region of the spinal column?

• cervical (7)

• thoracic (12)

• Lumbar (5)

• sacrum (5 fused)

• Coccyx (4 fused)

What is the function of the cervical vertebrae?

connect the head

allow for lots of movement

What is a distinct feature of the cervical vertebrae?

transverse foramen

*C1-C7 vary reatly but C are happy!

happy = big eyes (anterior)

What is the function of the thoracic vertebrae?

suspends ribs (and therefore the respiratory cavity)

so less flexible and more stable

What is a distinct feature of the thoracic vertebrae?

costal facets

What is the function of the lumbar vertebrae?

allow mobility between the thorax and pelvis

and support upper skeleton + extremities

What is a distinct feature of the lumbar vertebrae?

mamillary processes

(major muscle attachment for deep back muscles—- thhink mound of muscle)

What is the function of the Sacrum?

strongly binds vertebral column to the pelvic girdle

support body weigt + transmit upper extremity forces to lower extremities

What joint strongly binds the sacrum to the pelvic girdle?

sacroiliac joint

What are the curves of the spine listed Superior to Inferior?

• cervical- lordotic (tilt head back ‘oh lord’)

• thoracic- kyphotic (less mobile - stabilizes ribs)

• lumbar - lordotic (mobility between thoracic and sacral, LL)

• sacral- kyphotic (stable pelvic girdle)

Lordotic vs Kyphotic Curves

lordotic: more movement ‘loose’, convex anteriorly (tilt head back)

kyphotic: more stable (hard k sound), concave anteriorly

What vertebral landmarks are present in almost all vertebrae?

• vertebral body

• vertebral arche

• 7 processes

What are the 7 processes on a vertebra?

2 superior articular processes

2 inferior articular processes

2 transverse processes

1 sinous process

What 7 processes are on almost all vertebrae?

• inferior (2) + superior (2) articular processes

• transverse processes (2)

• spinal process

What happens to vertebrae size you move inferiorly?

vertebrae increase in size to accomodate for increasing load

What are the components of the vertebral body?

• trabeculae (spongy bone)

• ring of apophyses

• vertebral end plates

What forms the vertebral arch?

• pedicle (ventrally) - form sup/inf vertebral noches ‘walls of house’

• lamina (dorsal) ‘roof of house’

• spinous process (project from where lamina join)

The vertebral arch is primarily made of what type of bone?

cortical (hard)

Function of the spinous process

act as levers for back extensors

What are the zygapophyses?

articular processes from junctions of pedicles/laminae

What are the pars interarticularis?

between sup/inf facets

What is the function of the vertebral foramen?

house the spinal cord

What is the function of the intervertebral foramen?

‘highway exits’ for nerves

made from inferior + superior vertebral notches

What are the zygapophyses “facets”?

synovial joints between superior/inferior vertebrae

What does a defective pars interarticularis result in?

spondylolysis

What is spondolisthesis?

anterior displacement of the pars interarticularis

result in lower back, butt and post leg pain

Names for transitional vertebrae

cervicothoracic

thoracolumbar

lumbosacral

*morphologically change

What protects the spinal cord?

the vertebral arch

(the vertebral foramen is just the space that holds it)

Where are intervertebral discs located in the spine?

C2-S1

General characteristics of intervertebral discs (2)

• fibrocartilaginous

• relatively avascular

What are the structural components of the intervertebral discs?

nucleus pulposus (fibrous strands in proteoglycan gel) smallest in cervical

annulus fibrosis (concentric fibrocartilagenous + collagen bands) (annual- circular)

Nucleus pulposus

squishy part of intervertebral disc

fibrous strands in proteoglycan gel

smallest in cervical

Annulus Fibrosus

attaches rim of intervertebral disc to rim of vertebral body

concentric fibrocartilagenous / collagen bands

Function of intervertebral discs

major compression bearing

How do the intervertebral discs impact spine curvature?

deeper anteriorly in cervical + lumbar

contributes to anterior convex

(like stack of binders)

Ligament######

slide 33

Anterior Longitudinal Ligament

slide 34

PLL

slide 35

Ligamentum Flavum

slide 36

Supraspinous Ligament

extends from C7 to Sacrum

connects tips of spinous processes

relatively thick in the lumbar spine

break these cards out too***

When is the supraspinous ligament lax and when does it act as (inhibitor?)

2:15 slide 37

Interspinous Ligament

limitation in forward flexion and some rotational movements

Nuchal Ligament

continuous with supraspinous ligament

trianggle base of skull and C1-7 and T1, stability and head flexion gaurd

Intertransverse Ligament

between transverse processes

limit contralateral side-bending (lateral flexion)

Spinal cord

contained in vertebral canal

enlargements in gray matter in cervical in lumbar regions

gives off spinal nerves that combine in plexi to form peripheral nerves

developmentally cord segments initially line up with the bony vertebral column (eventully spine is longer)

Conus Medullaris- inferior end of spinal cord L2/3 (bellybuttonish)

filum terminale anchored to coccyx terminal nerves = cauda equina

This ligament limits contralateral side bending:

A. Nuchal

B. Intertransverse

C. Supraspinous

D. Anterior longitudinal

intertransverse

Intervertebral joints are classified as:

A. Synarthrosis

B. Amphiarthrosis

C. Diarthrosis

amphiarthrosis