The Lumbar Spine, Applied Anatomy and Clinical disorders

Question 1

how many vertebrae and what is it made up of

Answer 1

33 
5 lumbar
5sacral 
4 coocygeal 
12 thoracic 
7 cervical

Question 2

functions of lumbar spine

Answer 2

support
protection
movement
haematopoeisis

Question 3

why does the size of the vertebral body increase from superior to inferior

Answer 3

to resist the greater compressive forces distally

has to bear the weight of all of the structures above

Question 4

what types of movement does the interlocking design allow

Answer 4

flexion, extension, lateral flexion and rotation

prevents anterior displacement of vertebrae

Question 5

what types of joints in the lumbar spine

Answer 5

fibrous: non-mobile
secondary cartilaginous- partially mobile
synovial joints- highly mobile

Question 6

what does the intervertebral disc consist of

Answer 6

nucleus pulposus

annulus fibrosus

Question 7

annulus fibrosus

Answer 7

surrounds nucleus pulposus
type 1 collagen
made of lamellae of annular bands in varying orientations
avascular and aneural N

Question 8

nucleus pulposus

Answer 8

remanant of notochord 
gelatinous, type 2 collagen 
high oncotic pressure
centrally located in the infant
located more posteriorly in adult

Question 9

how does force transmission change with age

Answer 9

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

Question 10

vertebral column in

the fetus

Answer 10

flexed in a single curvature
c shaped
concave anteriorly = kyphosis
this curvature is known as primary curvature

retained in thoracic, sacral and coccygeal regions

Question 11

evolution of the spine in 18 months

Answer 11

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

Question 12

lordosis

Answer 12

concave posteriorly curvature

Question 13

kyphosis

Answer 13

concave anterior curvature

Question 14

verterbral column in adult

Answer 14

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

Question 15

what happens to the vertebral column in old age

Answer 15

secondary curvatures start to disappear

-loss of disc height and osteoporotic fractures

Question 16

what happens to the vertebral column in pregnancy

Answer 16

exaggeration of lumbar lordosis during pregnancy

Question 17

what does slouching do to the spine

Answer 17

compressed disc
pressure on nucles is more posterior
disc bulges posterior
disc prolapses susceptible

Question 18

what is mechanical back pain

Answer 18

pain when the spine is loaded
worse with exercise relived with rest
intermittent
triggered by innocuous activity

Question 19

aging physiology of spine

Answer 19

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

Question 20

what is prolapse

Answer 20

protusion of the nucleus pulposus into the spinal canal leading to compression of the nerve roots

Question 21

degeneration

Answer 21

disc bulge

Question 22

extrusion

Answer 22

nuclus pulposus breaks through annulus fibrosus but remians in disc space

Question 23

sequestration

Answer 23

nucleus pulposus breaks through annulus fibrous and separates from the main body of the disc in the spinal canal

Question 24

where is the most common site of a slipped disc

Answer 24

L4/5 L5/S1

Question 25

in what direction does a slipped disc herniate and what does this cause

Answer 25

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

Question 26

what is sciatica

Answer 26

pain caused by irritation or compression of one or more nerve roots which contribute to the sciatic nerve

Question 27

l4 sciatica

Answer 27

anterior thigh
anterior knee
medial leg

Question 28

l5 sciatica

Answer 28

lateral thigh, lateral leg , dorsum of foot

Question 29

s1 sciatica

Answer 29

posterior thigh, posterior leg, heel lateral border and sole of foot

Question 30

cauda equina syndrome

Answer 30

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

Question 31

symptoms of cauda equina syndrome

red flag symptoms

Answer 31

bilataral sciatica
perianal numbness 
painless retention of urine
urinary/ faecal incontinence 
erectile dysfunction 

SURGICAL EMERGENCY

Question 32

Lumbar canal stenosis

Answer 32

occurs in elderly
narrowing of nerve roots 
facet joint osteoarthiritis 
disc bulge
ligamentum flavum hypertrophy

Question 33

neurogenic claudication

Answer 33

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

Question 34

Spondylolisthesis

Answer 34

slip or movement between 2 vertebrae of the spine

caused by disconnection of the vetebral body from the vetebral arch

usually a forward displacement

Question 35

Between which spinous processes should a lumbar puncture needle be inserted when
obtaining a sample of fluid from the subarachnoid space?

Answer 35

L3/4

L4/5

Question 36

What anatomical landmark should

be used to help locate the correct plane?

Answer 36

The supracristal plane transects the highest points of the iliac crests and passes through the
L4 spinous process.

Question 37

In a paracentral herniation of the L5/S1 disc, which nerve root is most likely to be
compressed and why?

Answer 37

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.

Question 38

symptoms of spondylothesis

Answer 38

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.

Question 39

Which nerve is compressed in a disc prolapse of Lx/Lx +1

Answer 39

LX + 1