Vertebral Coloumn 1 and 2 Flashcards
Describe some general characteristics of the spine
- Segmented column consisting of bone
elements, intervertebral discs and ligaments - 5 different regions: cervical, thoracic, lumbar,
sacral, coccygeal (on average 24 presacral
vertebrae) - Antero-posterior view: column appears to be
straight - Lateral view: four dorso-ventral curves:
1) Cervical lordosis, 2) thoracic kyphosis, 3)
lumbar lordosis and 4) sacro-coccygeal kyphosis
Describe the joint facet orientation and spine movement for cervical, thoracic and lumbar spines
Joint facets facing superior and
inferior: flexion/extension,
lateral bending, rotation
Most mobile region of the spine
Joint facets facing anterior and
posterior: rotation
Least mobile region of the spine
Joint facets facing medial
and lateral: mostly
flexion/extension
Describe the postnatal development of spinal curves
Cervical lordosis: carrying the head
upright (starts around 6 months)
Thoracic kyphosis: already present
at birth but gets more accentuated
throughout postnatal development
Lumbar lordosis: upright
walking (starts around 12 months)
Sacrum and coccyx kyphosis: upright
walking (approx. same start as lumbar
lordosis)
Describe spinal curve development and growth
During postnatal ontogeny, the curves
mainly develop due to the adjustments
of the intervertebral disc height and
shape
* In later life – after skeletal maturation -
the vertebral body bone tissue
reorganises itself into wedge-shapes
that accentuate the curves
Describe vertebral growth patterns and explain what arm elements are
The neonate vertebrae have 2 separate
arch and 1 body element, connected
with cartilage which allows for the
growth of all parts of the vertebrae
* The arch elements are the first to fuse
between 1 - 6/7 years of age
* The united arch merges with the bodies
between 2 and 6 years on the presacral
spine and up to 12-25 years in the
sacrum and coccyx.
Scoliosis
A lateral curvature, combined
with a rotation is called a
scoliosis
The reasons why a scoliosis
develops are manifold and
range from congenital (e.g.
gene defects, developmental
issues) to neuromuscular (e.g.
muscular dystrophies) and
idiopathic (unclear cause
Example of congenital
scoliosis: Presence of a
hemi-vertebra induces
a scoliosis during
postnatal ontogeny
What are the issues with damaging the cervical rib- thoracic outlet syndrome?
Compression of the brachial plexus:
Can result in paraesthesia along the ulnar border of the
forearm, wasting of hypothenar and interossei muscles,
ulnar lumbricals and adductors of the thumb
Compression of the subclavian artery: Can simulate
and/or produce an aneurysmal dilation of the artery
and related complications (e.g. thrombi)
Describe lumbar ribs
A supernumerary rib which arises
from a lumbar vertebra (L1) –
often, a transverse foramen is
present as well
* Located below the normal last
floating rib (rib pair 12)
* Genetically (congenitally) induced
– hox gene activity
* Frequency is likely higher than
that of cervical ribs but appears
rare due to not being reported
much in clinical imaging
* Lumbar ribs are not generally
associated with medical
conditions (hard to spot)
Describe spondylolysis
A deformation/defect or a stress fracture of the vertebral arch (pars inter-articularia)
and/or articular processes
- Caused by overload of the lumbar spine – but a genetic component is often
involved as well, where this part of the vertebra is less than average tall
Spondylolysis can result in one or more vertebrae becoming unstable and slipping out
of place = Spondylolysthesis
Describe intervertebral discs
Between all neighbouring vertebrae,
there is a fibrocartilaginous joint, made
by the intervertebral disc (exception:
C1-C2)
* The discs have a fibrocartilaginous outer
ring – the annulus fibrosus and a gellike fluid core – the nucleus pulposus
* There are two cartilaginous endplates
made of hyaline cartilage which anchor
the disc to the bone of the vertebral
body
Describe the structure of intervetebral discs
Annulus fibrosus: layers of
fibrocartilage and collagen
fibres organized in
alternating directions and
layers
- Nucleus pulposus: gel-like
fluid contained within the
annulus fibrosus - No nucleus pulposus
between C1 and C2 and in
the sacrum and coccyx
Describe the ageing disc and associated injuries
After 40 years of age, more than half the population will have
some degree of disc degeneration due to:
* A dehydrating nucleus pulposus which leads to lesser
ability of the disc to shock-absorb
* The annulus fibrosus becomes weaker and the endplates tend to be more brittle
All this can lead to a loss of height, but these changes are
natural wear-and-tear and the process is pain free.
The more brittle annulus fibrosus and cartilaginous endplates
can lead to:
* Tears in the annulus fibrosus and the endplates
* Bulges and protrusions – temporary or permanently of
the annulus fibrosus into the vertebral canal or the
intervertebral foramina
* Herniating or extruding nucleus pulposus through a rent
in the outer layers of the annulus fibrosus or the endplate
Describe the ligaments of the vertebral body and lamina
Anterior and posterior
longitudinal ligaments:
continuous bands from skull
to sacrum, on anterior and
posterior surfaces of the
vertebral bodies
Ligamenta flava: connect
the vertebral arches; they
are highly elastic hence their
yellow appearance (flavum =
yellow, lat.)
What are the ligaments of the atlanto-occipital area
Alar ligaments
Transverse atlantic ligament
Longitudinal fascicles
Together = cruciform ligament
What are the types of intrinsic back muscles
Longitudinal muscles – together
known as the Erector spinae – are
mostly involved in antagonising
flexion and faciliate extension of
the vertebral column and skull
* Iliocostalis
* Longisssimus
* Spinalis
Transverse (or rotator) muscles –
they are important for rotating
and bending the spine as a whole
and neighbouring vertebrae
against each other
* Most prominent in the lumbar
region: Multifidus
What is thoracolumbar fascia
The thoracolumbar fascia covers the intrinsic back muscles and is continuous with the superficial lamina of the
deep cervical fascia at the back of the neck
- In the lumbar region the fascia consists of three layers;
↙ = posterior/superficial, ↗ = middle and
↓ =anterior/deep, enclosing the erector spinae muscles in one compartment and the quadratus lumborum in
another
What are the boundaries of the spinal canal
Continuous tube formed by
the stacked vertebrae C1-S5
(and intervertebral discs)
- Anterior boundary: vertebral
body and posterior
longitudinal ligament - Posterior boundary: Vertebral
arches and ligamenta flava - Lateral openings
(intervertebral foramen)
between pairs of vertebrae
What are the contents of the spinal canal
Epidural fat pad (contains
internal venous plexus)
* Meninges of the spinal
cord (continuous with the
meninges of the cerebrum)
and cerebrospinal fluid
* The spinal cord itself
What are the 3 membranes that envelope the CNS and spinal cord
Tubular extension of the central nervous system;
transmission of neural inputs between the periphery and the brain
System of 3 membranes which envelope the central
nervous system and the spinal cord:
* Dura mater
* Arachnoid mater (Subarachnoid space)
* Pia mater
What is cerebrospinal fluid
Produced in the choroid plexi
of the lateral ventricles of the
cerebrum (see NSB module later
this term)
* Circulates via 3rd and 4th
cerebral ventricles and the
median and lateral apertures
of the 4th ventricle around the
cerebrum and cerebellum and
the spinal cord
* Drains via cerebral sinuses
and likely roots of spinal
nerves
Describe dura matter
Outer-most layer, a thick, fibrous sheet
* Fused partially to the periosteum of the
skull bones (see NSB module later this
term), at spinal level tethered to foramen
magnum and 2nd sacral vertebra only
* Separated from spinal canal walls by the
epidural fat and vessel layer
* Dura is drawn out with the spinal nerves
via the intervertebral foramina
* Small, capillary space between dura and
arachnoid mater = subdural space
(marked green on slide)
* Highly sensitive to pain, innervation by
trigeminal and vagus nerves (NSB)
Describe arachnoid matter
Middle layer
* Sends web-like fascicular
processes towards the
pia mater and attaches
to it
* “Space” between
arachnoid and pia mater
= subarachnoid space is
filled with cerebrospinal
fluid
Describe pia mater
Inner most layer, delicate,
thin membrane, difficult
to dissect off the spinal
cord
* Highly vascularised
* Attaches to the Dura
mater (piercing through the
arachnoid mater) via
denticulate ligaments
What are the extensions of the spinal chord
Caudal extension of the central nervous
system (intra-cranial = medulla
oblongata)
* Lower cervical/upper thoracic
enlargement
* Lumbar enlargement
* The spinal nerves emerging from the
lumbar and sacral segments form the
Cauda equina (= horsetail)
Describe spinal chord growth from neonate to adulthood
The spinal cord and the
vertebral column follow
different growth patterns
from around the 9th fetal
month because
musculoskeletal structures
have a longer growth
period than neural ones
* Newborn: Conus
medullaris at level of
L3/L4
* Adult: Conus medullaris
at level of L1/L2
What is the position of the spinal nerves in relation to the vertebral column
Only spinal nerves of the cervical
region are level with their respective
vertebrae
* Spinal nerves of the lumbar and sacral
regions deviate strongly from their
vertebral levels and form the Cauda
equinae
* In the lumbosacral region, the spinal
nerves run through the lumbar cistern
Describe filum terminale
Filum terminale (= extended strand of pia
mater) which emerges through the
arachnoid mater and attaches to the
sacrum, at S2 level, surrounded by
strand of dura mater, which attaches
there as well.
- The extension of dura and arachnoid
mater to level of S2 forms a large
forms a large subarachnoid space =
lumbar cistern in that area, which is a
reservoir for CSF
What is the clinical relevance for the spinal cord ending at L1
The termination of the spinal
cord at level L1 has clinical
relevance:
- The subarachnoid space and the
lumbar cistern are “easy” access
points (either lumbar or sacral) for: - Samples of CSF
- Introduction of contrast agents
(radiology) - Administration of anaesthetic
and analgesic blocks
Describe spinal anaesthesia
An anaesthetic agent is injected into the
subarachnoid space, into the cerebrospinal
fluid
- Using a “heavy weight” agent, distribution
up or down the spine and unilateral
administration can be achieved - Only small amounts of agent needed, fast
acting (< 5 minutes) - Is usually not administered above the level
of L1 (danger of spinal cord damage) - Suitable for surgical procedures of the lower
abdomen, pelvis and lower limbs
How does epidural anaesthesia work
Agent is placed in the epidural space, no
meninges are punctured
* Pain relieve not as fast as spinal
anaesthesia
* Theoretically applicable everywhere on
the spine
* Larger amounts of agent fluid needed
* Catheter can be inserted for “top-up”
* Does not result automatically in a neuromuscular block – important when used in
labour pain control
How does blood supply to the spine work
Spinal cord and spinal nerve root supply:
* From 1 anterior and 2 posterior spinal arteries, arising from the
vertebral arteries (cervical region)
* In the thoracic and lumbar region, the spinal arteries are supplied
via the segmental arterial branches: thoracic = posterior
intercostal arteries, lumbar = lumbar arteries. These are
connected to the spinal arteries via radicular arteries
Vertebral and intervertebral disc supply:
* Segmental spinal arteries - cervical = vertebral arteries, thoracic =
posterior intercostal arteries, lumbar = lumbar arteries give off
periosteal arteries
* Periosteal arteries supply the bone tissue and - via a network of
metaphyseal anastomoses - the intervertebral discs
Describe blood drainage of the spine
External venous plexus
* Located within the muscles lying posterior to the transverse
processes, spinous processes, articular processes and the laminae
of the vertebrae
Internal venous plexus
- Located within the vertebral canal but outside of the dura mater
(i.e. between dura mater and ligamentum flavum) - Drains blood from vertebral bodies and spinal cord
- Exits with the spinal nerves through the intervertebral foramina
and connects with external venous plexus
Drainage to segmental veins of the body wall: cervical =
vertebral veins, thoracic = posterior intercostal veins, lumbar =
lumbar veins
Blood flow is multidirectional - cancers of the pelvis and
abdomen can spread into the thorax this way
Describe injuries to the intervertebral disc
- Disc herniations: The nucleus pulposus herniates (fully or
partially) through a rent in the outer layers of the
annulus fibrosus - A herniation of the nucleus pulposus can occur in any
direction but is mostly concentrated in postero-lateral
positions due to the position of the posterior (and
anterior) longitudinal ligament(s) - The nucleus pulposus is still confined within the annulus
fibrosus - Most minor herniations/bulges heal within several weeks
- Disc protrusions: Can develop from a previously existing
disc herniation, where the outermost layers of the
annulus fibrosus are still intact. When these layers
rupture, disc material can protrude into the vertebral
canal, particularly when under pressure
What reflexes are indications of their spinal nerve roots
Biceps jerk - C6
* Triceps jerk - C7
* Knee (quadriceps tendon) jerk - L3 (L4,
L2 admixture)
* Ankle (Achilles tendon) jerk - S1 (L5
admixture)
