The Lumbar Spine, Applied Anatomy and Clinical disorders Flashcards
how many vertebrae and what is it made up of
33 5 lumbar 5sacral 4 coocygeal 12 thoracic 7 cervical
functions of lumbar spine
support
protection
movement
haematopoeisis
why does the size of the vertebral body increase from superior to inferior
to resist the greater compressive forces distally
has to bear the weight of all of the structures above
what types of movement does the interlocking design allow
flexion, extension, lateral flexion and rotation
prevents anterior displacement of vertebrae
what types of joints in the lumbar spine
fibrous: non-mobile
secondary cartilaginous- partially mobile
synovial joints- highly mobile
what does the intervertebral disc consist of
nucleus pulposus
annulus fibrosus
annulus fibrosus
surrounds nucleus pulposus
type 1 collagen
made of lamellae of annular bands in varying orientations
avascular and aneural N
nucleus pulposus
remanant of notochord gelatinous, type 2 collagen high oncotic pressure centrally located in the infant located more posteriorly in adult
how does force transmission change with age
young
- 80% of body weight through vetebral joints
- 20% through facet joints
elderly
-disc dehydration
-greater forces through the facet joints
65% vetebral bodies 35% facet joints
vertebral column in
the fetus
flexed in a single curvature
c shaped
concave anteriorly = kyphosis
this curvature is known as primary curvature
retained in thoracic, sacral and coccygeal regions
evolution of the spine in 18 months
the primary curvature is remodelled to add 2 secondary curvatures
the cervical spine develops the first posterior concavity (cervical lordosis) when young child begins to lift its head
lumbar spine loses its primary kyphosis during crawling
when the child begins to stand up and walk, lumbar lordosis which is the second curvature
lordosis
concave posteriorly curvature
kyphosis
concave anterior curvature
verterbral column in adult
5 distinct curvature
sinusoidal profile- flexible and resilience
3 kyphosis (anterior concavities|); thoracic and sacrococcygeal- continuations of the primary curvature of the foetus
2 lordosis (posterior concavities) - cervical and lumbar secondary curvatures
what happens to the vertebral column in old age
secondary curvatures start to disappear
-loss of disc height and osteoporotic fractures
what happens to the vertebral column in pregnancy
exaggeration of lumbar lordosis during pregnancy
what does slouching do to the spine
compressed disc
pressure on nucles is more posterior
disc bulges posterior
disc prolapses susceptible
what is mechanical back pain
pain when the spine is loaded
worse with exercise relived with rest
intermittent
triggered by innocuous activity
aging physiology of spine
nucleus pulposus dehydrates with age
loss of disc height- disc bulge
increased load stresses- reactive marginal osteophytosis and the end plates called syndesmophytes
increased load stress on the facet joints- facet joint osteoarthritis
what is prolapse
protusion of the nucleus pulposus into the spinal canal leading to compression of the nerve roots
degeneration
disc bulge
extrusion
nuclus pulposus breaks through annulus fibrosus but remians in disc space
sequestration
nucleus pulposus breaks through annulus fibrous and separates from the main body of the disc in the spinal canal
where is the most common site of a slipped disc
L4/5 L5/S1
in what direction does a slipped disc herniate and what does this cause
paracentrally as the posterior longitudinal ligament sits in the midline over the back of the annulus. It reinforces the annulus. The weakest point is at the lateral edge of the PLL where it joins the annulus therefore prolapses occur at the right or left hand side more commonly
this causes compression of the spinal nerve roots
what is sciatica
pain caused by irritation or compression of one or more nerve roots which contribute to the sciatic nerve
l4 sciatica
anterior thigh
anterior knee
medial leg
l5 sciatica
lateral thigh, lateral leg , dorsum of foot
s1 sciatica
posterior thigh, posterior leg, heel lateral border and sole of foot
cauda equina syndrome
canal-filling disc compressing the lumbar and sacral nerve roots
2% all prolapsed intervetrebral discs are canal filling
all nerves in lower limb become compressed
symptoms of cauda equina syndrome
red flag symptoms
bilataral sciatica perianal numbness painless retention of urine urinary/ faecal incontinence erectile dysfunction
SURGICAL EMERGENCY
Lumbar canal stenosis
occurs in elderly narrowing of nerve roots facet joint osteoarthiritis disc bulge ligamentum flavum hypertrophy
neurogenic claudication
pain in legs when walking compression of nerve roots leads to venous engorgement of nerve roots during exercise leads to reduced arterial flow leads to pain and parasthesia
RELIEVED WITH REST AND FLEXION OF SPINE
Spondylolisthesis
slip or movement between 2 vertebrae of the spine
caused by disconnection of the vetebral body from the vetebral arch
usually a forward displacement
Between which spinous processes should a lumbar puncture needle be inserted when
obtaining a sample of fluid from the subarachnoid space?
L3/4
L4/5
What anatomical landmark should
be used to help locate the correct plane?
The supracristal plane transects the highest points of the iliac crests and passes through the
L4 spinous process.
In a paracentral herniation of the L5/S1 disc, which nerve root is most likely to be
compressed and why?
The S1 nerve root is the traversing root and is most likely to be compressed by a paracentral
herniation. The L5 root is likely to pass superior to the disc herniation and be unaffected.
symptoms of spondylothesis
Some individuals remain asymptomatic, but most complain of some discomfort ranging from
occasional lower back pain to incapacitating mechanical pain, sciatica from nerve root
compression, and neurogenic claudication.
Which nerve is compressed in a disc prolapse of Lx/Lx +1
LX + 1
