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