Vertebral column anatomy

What helps anchor the SC laterally?

denticulate ligaments (lateral extensions of pia mater between dorsal and ventral roots)

The basivertebral veins connects what?

epidural venous plexus with external venous plexus

Helps anchor SC inferiorly

external filum terminale

Between superior and inferior articular processes of adjacent vertebrae

facet joints

What are the joints between the articular processes called?

facet joints

What position do pts have to lie in when getting a lumbar spinal tap? Why?

fetal position (vertebral column flexed). Spreads lamina and spinous processes apart

What extends from the terminal portion of the SC?

filum terminale (vestigial remnant of the caudal SC = tail of the embryo)

What is formed with the sacral vertebrae?

forms sacrum (5 sacral vertebrae fuses in adults)

What is the largest of the segmental arteries?

great anterior segmental artery of Adamkiewicz

How do the remaining spinal nerves T1 to Co1 traverse through their intervertebral foramen?

inferior to vertebrae of the same number (of the corresponding vertebra)

Venous blood from the spinal cord drains into the anterior and posterior spinal veins which course along the surface of the cord. Where do these spinal veins ultimately drain?

internal or epidural venous plexus (within vertebral canal) > (epidural venous plexus connects with external venous plexus via *basivertebral veins* which drains the vertebrae)

Adjoin adjacent spinous processes

interspinous ligament

Spinal nerves exits through the

intervertebral foramina

What will you find between the IV disc and facet joints?

intervertebral foramina (spinal nerve exits)

Where does the great anterior segmental artery of Adamkiewicz arise from?

lower intercostal artery (left side ~65%)

Lumbosacral enlargement innervates the

lower limbs

What is the idea site to get a sample of CSF (spinal tap)?

lower lumbar (L3, L4, L5; bc SC terminates at about L2)

This vertebrae is large and massive for weight bearing

lumbar (tree ko lumbar is heavy)

Cauda Equina (horse's tail)- composed of dorsal and ventral roots of _____ and _____ spinal nerves

lumbar and sacral

As a result of the disproportionate growth of the spinal cord compared to the vertebral column, what must grow the longest?

lumbar and sacral/coccygeal (aka cauda equina)

Thin, innermost membranes which firmly adheres to the surface of the SC

pia mater

Some branches of the spinal nerves (*ventral rami*) come together and form

plexuses (brachial and lumbosacral that innervates limbs)

Posterior spinal artery is aka

posterior cerebellar artery

What may happen to the facet joint as we age? What is the implication of this?

may become arthritic (exiting spinal nerve can become impinged resulting in pain)

Where does the internal filum terminale extend from and to?

medullary cone to tip of dural sac

Purpose of the numerous (7) processes in a vertebrae

muscle attachment and joint surfaces

Purpose of ligamentum flavum

prevent hyperreflexion of the vertebral column

Purpose of the vertebral (neural) arch? What does it consist of?

protection of SC (consists of pedicles and laminae)

What is a small artery that vascularizes the dorsal and ventral roots?

radicular arteries (does NOT reach or communicate with spinal arteries)

Segmental medullary arteries are branches that arise from

nearby arteries (ascending cervical arteries, deep cervical arteries, intercostal arteries, lumbar arteries, lateral sacral arteries)

Purpose of intervertebral foramina?

passage and protection for spinal nerve as it exits

The supra*spinous* ligament connects *spinous* processes from _____ to _____

sacrum to C7 (expands into ligamentum nuchae in cervical region)

Irregularly spaced vessels that communicate (anastomosis) with longitudinal spinal arteries

segmental or horizontal arteries

Ligaments that would be traversed as one performs a lumbar puncture

skin > supraspinous ligament > interspinous ligament > ligamentum flavum > epidural space > dura mater > arachnoid mater > subarachnoid space!

Small arteries that vascularize the dorsal and ventral roots but don't communicate with spinal arteries

small radicular arteries

Spinal nerves arise from each spinal cord segment via _______ that eventually

small rootlets; converge to form two roots (a ventral & dorsal root); unite to form spinal nerve (with both sensory and motor axons)

Membranes that surround the SC are referred to as

spinal meninges

What does the dorsal and ventral root unite to form?

spinal nerve (with both motor and sensory axons)

Initially during development, the spinal cord occupies the entire length of the vertebral column, but as development progresses the vertebral column grows longer than the spinal cord. What must lengthen to still be able to supply its assigned are?

spinal nerve roots

What is the procedure that is performed to obtain sample of the CSF?

spinal tap

Supraspinous ligament connets what?

spinous processes from sacrum to C7

Why do pts have to lie in fetal position with vertebral column flexed to get a lumbar spinal tap (CSF)?

spreads lamina and spinous process apart

Purpose of facet joints

stabilize, flexion, extension, rotation

How do C1-C7 traverse through their intervertebral foramen?

superior to vertebrae of the same number (C4 spinal n exits the foramen between C3 and C4)

Purpose of spinal meninges?

support and protect SC, nerve roots, cauda equina

Functions of vertebral column

supports head and trunk, transfers weight of body to lower limbs, provides a flexible yet rigid axis for our body (postural support), encloses and protects SC

What expands into ligamentum nuchae in cervical region?

supraspinous ligament

What kind of joints are the facet joints?

synovial

Although the vertebral column consists of 33 vertebrae, motion occurs only between the 24 vertebrae. What is the implication of this?

these 24 vertebrae gradually become larger as the vertebral column descends in order to support increasing amount of body weight

This vertebrae articulates with the ribs

thoracic (think thoracic cavity = ribs)

How does the arachnoid mater attach to the pia mater?

through small septal-like projections or trabeculae from the inner surface of arachnoid

Where does the external filum terminale extend from and to?

tip of dural sac to sacrum/coccyx (helps anchor SC inferiorly)

Purpose of the vertebral body

weight bearing

Purpose of IV discs

weight bearing and strength

Designed for weight bearing and strength

IV disc, vertebral body, lumbar

What are the joints between the vertebral bodies called?

IV discs

What does the epidural space contain?

adipose tissue and epidural venous plexus

What do the ligamentum flavum join together?

adjacent lamina of vertebrae

What does the dorsal root contain?

afferent axons

Venous drainage of SC

anterior and posterior spinal veins > internal or epidural venous plexus > via basivertebral veins > external venous plexus

Prevents hyperextension

anterior longitudinal ligament

Where does the dural sac start and end surrounding the spinal cord?

base of the skill to S2

Where does the spinal cord extend out from and to?

base of the skull to L2 (sometimes L1)

Where is the epidural space?

between vertebral canal and dura mater

What are the two enlargements of the SC?

cervical and lumbosacral

What is formed with the coccygeal vertebrae?

coccyx (4 coccygeal vertebrae fuses to form coccyx/tailbone)

What makes up the cauda equina?

collection of lumbar and sacral/coccygeal nerve roots

The subarachnoid space in SC is _______ with the subarachnoid space surrounding the brain

continuous

What is the terminal portion of the SC referred to as?

conus medullaris (L1~L2 vertebral level)

What structures will you find in L1~L2 vertebral level?:

conus medullaris, filum terminale

What may happen to the intervertebral foramina as we age? What is the implication of this?

decrease in size, surrounding bone impinges on spinal nerve (pain)

What is arachnoid mater? Where is it found?

delicate, intermediate membrane, lines the inside of the dura and dural sleeves

Interposed between bodies of adjacent vertebrae

IV disc

*Is the subarachnoid space continuous with the subarachnoid space surr the brain?*

*YES*

What fraction of the vertebral canal does the spinal cord occupy?

2/3

Vertebral column in an adult typically consists of 33 vertebrae arranged in 5 regions. However, motion only occurs between ____ vertebrae. What are they?

24 (7 cervical, 12 thoracic, 5 lumbar)

Spinal cord has _____ spinal cord segments and ____ pairs of spinal nerves

31

How many spinal nerves does the SC have?

31 (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal)

Vertebral column in an adult typically consists of _____ vertebrae arranged in _____ regions. What are they?

33 vertebrae, 5 regions; cervical (7), thoracic (12), lumbar (5), sacral (5), coccygeal (4)

Which vertebrae fuse to form a structure?

5 sacral and 4 coccygeal (sacrum and coccyx)

There are ____ cervical nerves and ___ cervical vertebrae

8 nerves; 7 vertebrae

How many segmental medullary arteries do we have?

8-10 (enter through intervertebral foramina)

Numerous ligaments help stabilize and support the vertebral column including

Anterior Longitudinal Ligament, Posterior Longitudinal Ligament, Supraspinous Ligament, Interspinous Ligaments, Ligamentum Flava

What is the interconnecting vertebral venous plexuses aka?

Batson's plexus

________________ may account for the spread on certain cancers (prostate) into the vertebral column

Batson's vertebral venous plexus

What accounts for the fact that cancer cells from the prostate (and some other cancers...lung/breast) can travel and sequester within the vertebral column resulting in bone cancer...or travel into the cranial cavity resulting in metastatic brain cancer?

Batson's vertebral venous plexus (communicates with veins in cranial cavity (dural venous sinuses), veins in pelvis and along posterior thoracic wall)

There are 8 cervical nerves and 7 cervical vertebrae. How is this issue resolved?

C1-7 traverse through their corresponding intervertebral foramen superior to vertebrae of the same number; C8 traverses through inferior aspect of C7 (the foramen between C7 and T1 vertebrae)

What's in the subarachnoid space?

CSF

Articulations that connect the heads of the ribs with the bodies of the thoracic vertebrae

Costovertebral joints

Conus Medullaris- termination of the adult spinal cord is approximately

L1/L2

Where should a spinal tap be performed?

L3, L4, L5

What does the vertebral canal house + protect?

SC and meninges

What is the correct order of tissues/ligaments that the needle would traverse in order to collect a sample of the CSF?

Skin→ Supraspinous Ligament → Interspinous Ligament → Ligamentum Flavum → Epidural Space → Dura Mater → Arachnoid Mater → Subarachnoid

Spinal cord is vascularized by longitudinal arteries that arise mainly from the _____________ and ____________ (artery of Adamkiewicz) that enter the vertebral column via ___________

Spinal cord is vascularized by longitudinal arteries that arise mainly from the *vertebral arteries* and *segmental medullary arteries* (artery of Adamkiewicz) that enter the vertebral column via the *IV foramina*

What kind of joint is the IV disc?

cartilaginous

Nerve roots that arise from the lumbosacral enlargement and medullary cone form the

cauda equina

Extends laterally into each IV foramina along the dorsal and ventral roots of spinal nerves and form the *dural sleeve*

dura mater

What are the membranes that surround the SC (spinal meninges)?

dura mater, arachnoid mater, pia mater

What does the ventral root contain?

efferent axons

What does the great anterior segmental artery of Adamkiewicz vascularize?

inferior 2/3rd of SC

How does C8 traverse through its interverteberal foramen?

inferior aspect of C7 (foramen between C7 and T1)

What are denticulate ligaments?

lateral extension of pia mater (between dorsal and ventral roots - helps anchor cord laterally)

Yellow ligament

ligamentum flavum

Yellow, elastic fibers adjoin adjacent lamina of vertebrae

ligamentum flavum (prevent hyperreflexion)

Broad strong ligament of the neck that provides attachment for cervical muscles

ligamentum nuchae

Purpose of anterior longitudinal ligament

unites anterior surfaces of the bodies of the vertebrae (prevents hyperextension)

Purpose of posterior longitudinal ligament. Where is it located?

unites posterior surface of the bodies of the vertebrae (thus located *inside* the vertebral canal)

Cervical enlargement innervates the

upper limbs

What do the interconnecting vertebral venous plexuses / Batson's plexus have direct venous connections with?

veins in the *pelvis*, along *posterior thoracic wall*, veins inside *cranial cavity* called dural venous sinuses

What artery do the anterior spinal artery and posterior spinal artery arise from?

vertebral arteries

Cervical vertebrae have transverse foramen for the ________

vertebral artery

What are the 3 main features of most all vertebrae?

vertebral body, vertebral (neural) arch, numerous (7) processes

What does stacking successive vertebrae together create throughout the length of the vertebral column?

vertebral canal

What do the interconnecting vertebral venous plexuses run along?

vertebral column

All vertebrae have a _________ that surrounds and protects the spinal cord

vertebral foramen

Consists of pedicles and laminae

vertebral/neural arch (protects SC)

Blood supply to the SC is derived from both _____ and _____ components. Both components are necessary to insure adequate blood supply to the cord

vertical (longitudinal) and horizontal (segmental)

What vascularizes the superior portions of the SC?

vertical or longitudinal arteries (anterior spinal artery and 2 posterior spinal arteries)

What are some features of the interconnecting vertebral venous plexuses (Batson's plexus)?

very few valves (if any; allows blood to flow unimpeded up and down the vertebral column), connections with veins in pelvis and along posterior thoracic wall, cranial cavity's dural venous sinuses

Purpose of filum terminale?

vestigial remnant (tail of embryo)

Facet joints are aka

zygapophysial joints