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Session 10
Thoracic and Lumbar spine
Sacroiliac joint
• Anatomy and biomechanics of the thoracic spine
• Conditions and management
• Lumbar spine anatomy and biomechanics
• Intervertebral disc in health and disease
• Conditions affecting the lumbar spine and management
• Sacroiliac joint anatomy - brief look at what can go wrong
Typical thoracic vertebra
• The body of the vertebra has equal transverse
and antero-posterior diameter
• There are demi-facets on the posterolateral
aspect of the vertebral body for articulation
with the ribs
• The transverse processes are thickened for
articulation with the tubercle of the rib (Cf
later)
• The superior zygapophyseal facets face
superiorly and laterally, orientated for rotation
movement
• The spinous processes slope downwards and
overlap the adjacent vertebra below
Articulation of the rib with the thoracic
vertebra
• The head of the rib articulates with the
demi-facet of the vertebra above and
below
• It also articulates with the intervertebral
disc
• The radiate ligament, not shown, fans out
from the head of the rib to attach it to
the vertebra above and below and to the
disc between
• The back of the rib articulates with the
transverse process
• The tip of the rib articulates with costal
cartilage which attaches to the sternum
Articulation of ribs with sternum
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Ist rib articulation is fibrocartilaginous
Ribs 2-7 synovial joints with sternum
5 remaining false ribs attach indirectly to the sternum
Ribs 11 and 12 have no attachment to the sternum and
are termed floating ribs
• Tip of the sternum termed the xiphisternum
• Joint between the manubrium and sternum
• Costal cartilages ossify with age
Ligaments of the thoracic region
• Ligamentous support structure is the
same as for the cervical spine
• The anterior longitudinal ligament and
ligamentum flavum are thicker than in
the cervical region
• Extensors of the thoracic
region
Intercostal muscles
• Much controversy about functions of the
intercostal muscles
• Widely thought that the external intercostal
muscles have a role in inspiration and the
internal intercostals have an expiratory
function
Rib movement during respiration
• Inhalation - the diaphragm moves down
whilst the ribs move upwards and
outwards
• The action is like a bucket handle lifted
away from the side of a bucket
Sympathetic chain
• Sympathetic trunk runs parallel to the thoracic
spine
• Part of the nervous system responsible for fight or
flight responses
• Raising the heart rate and blood pressure
• Increasing rate of respiration
• Release of blood sugars from the liver
• Intercostal nerve supplies the
intercostal muscles and skin of the
chest wall
Thoracic rotation
• Arms across chest localises movement to the
thoracic region
• Generally the range of movement is 30 degrees
• Rotation in the upper thoracic spine is more
restricted
• Complex rib movements also occur with all thoracic
movements
Thoracic flexion/extension
Side bending in the thoracic spine
• Again the range of side bending in the
upper thoracic region is less than for the
mid to lower regions
• Side bending also occurs with rotation of
the vertebral body
• Again there is complex movement of the
ribs with spinal movement
Thoracic conditions
• Usually associated with postural problems such as kyphosis, scoliosis
• Although the majority of cases of thoracic pain are mechanical there is a
higher incidence of serious pathology
• OA of the facet joints, rib articulation can cause pain, stiffness and irritation
of the intercostal nerves
• Inflammatory disorders such as ankylosing spondylitis diagnosed in
teenagers and young adults affects the thoracic spine
• Disc prolapses occur less frequently in the thoracic spine but can cause
spinal cord compression, as discussed for the cervical spine
• Wedge fractures may be due to osteoporosis or can be due to spinal
metastases or other bone cancers such as multiple myeloma
Internal structure of thoracic vertebral body:
Within a thin shell of compact bone, a series of vertical trabeculae
(loadbearing beams) are “tied together” by transverse trabeculae (crossties) which resist buckling of the vertical trabeculae under axial load.
Section of thoracic vertebral body
X-ray of mid thoracic region
from cadaver spine
Osteoporosis:
Predominantly affects postmenopausal women and
generally affects men about a
decade later.
The x-ray shows collapse of the
vertebral endplates with marked
increase in endplate concavity or
loss of vertebral height.
The decreased bone density of
the internal cancellous bone
contrasts with the preservation of
the peripheral compact shell.
Adequate calcium, hormones &
exercise can prevent it
Loss of
bone
density
Increased
concavity
Loss of
height
Lumbar vertebra
• The body of the lumbar vertebra is enlarged with
a greater transverse than anterior diameter
• The spine is broad and thick for muscle
attachment
• The facet joints are more vertically orientated
• The superior facets are concave and face medially
(inwards)
• The inferior facets are convex and face laterally
L5 vertebra articulating with the sacrum
• The L5 vertebra has a wedge shaped body with a
greater height anteriorly compared with posteriorly
• The spinous process is smaller
• The transverse processes are large and directed
superiorly and posteriorly
• The inferior facets are adapted for articulation with
the sacrum and are widely spaced
The intervertebral disc
• Vertebral endplate – thin layer of cartilage, fibres
organised horizontally to resist pressure from the nucleus
• The endplate has multiple perforations for nutrition of
the disc from the blood supply within the vertebral body
• The intervertebral discs make up 20-30% of the length of
the spinal column
• They increase in size being smallest in the cervical spine
and largest in the lumbar spine
• The L5/S1 disc is the largest
• The ratio of disc to vertebral body is greatest in the
cervical and lumbar spines, making these two regions
relatively more mobile
• The disc has two portions - the central nucleus pulposus
and the peripheral annulus fibrosus
• The nucleus and annulus are composed of water, collagen
and proteoglycans. The relative proportions and the type
of collagen varies
• Fluid and proteoglycans concentrations are greatest in the
nucleus and reduced in the annulus
• Collagen concentrations are greatest in the annulus
Structure of the nucleus and annulus
• Nucleus contains glycosaminoglycans linked
to proteins forming large molecules of
proteoglycans
• The molecule has a number of sidechains
one of which is chondroitin 4–sulphate which
attracts and retains water
• Fluid content of the nucleus decreases with
age
• Diurnal pattern water lost from the disc
when loaded continuously for several hours
• Collagen is present in high concentration as
resistant to compressive forces
• Forms 6-25% dry weight of nucleus rising to
70% dry weight of outer annulus
• Nucleus primary collagen II
• Annulus subject to tensile and compressive
forces, contains more type I than II collagen
Ligaments of the lumbar spine
• The upper and lower vertebral bodies and
interposed disc form the intervertebral
cartilaginous joint
• The zygapophyseal or facet joints are synovial
joints
• The ligaments associated with the facet joints
resist flexion of the lumbar spine and protect the
disc from shearing forces
• The anterior longitudinal ligament has deep
fibres which reinforce the disc anteriorly
• The posterior longitudinal, ligamentum flavum,
interspinous and supraspinous ligaments are as
for the other regions of the spine
Sacroiliac joint
• 5 sacral vertebrae are fused to form the sacrum
• The 1st segment has a facet for articulation with L5
• The 5th segment has a facet for articulation with
the coccyx
• The sacroiliac joint is formed by an L shaped
articular surface on the sacrum and corresponding
surface on the ilium
• The articular cartilage on the iliac side is
fibrocartilage whilst on the sacrum it is hyaline
cartilage
• The joint is part fibrous and part synovial
• The surfaces of the cartilage are smooth in children
but become a series of peaks and troughs in
adulthood
• The iliolumbar ligament originates from the
transverse processes of L5 and L4 and
attaches to the iliac crest
• The ligament is strong and plays an
important role in preventing the L5 vertebra
from sliding anteriorly
• The sacroiliac ligament extends from the iliac
crest to the tubercles of the first 4 sacral
vertebra
• The sacrospinous ligament connects the
ischial spines to the lateral border of the
sacrum and coccyx
• The sacrotuberous ligament connects the
ischial tuberosity to the posterior spines of
the ilia and the lateral border of the sacrum
and coccyx
• Fibres from the hamstring muscles also
blends with the sacrotuberous ligament
Symphysis Pubis
• The symphysis pubis is a cartilaginous joint
between the ends of the pubis bones
• The end of the pubic bone is covered by
articular cartilage
• Interposed between the bone ends is a
fibrocartilaginous disc
• 3 ligaments support the joint, superior,
inferior and posterior
• Muscle fibres from the abdominals and
adductors cross from each side of the
pubic rami to add support to the joint
The cauda equina
• The spinal cord terminates between T12 and L1
• The terminal point is termed the conus
medullaris
• The spinal nerves from L2-S5 are given off in
this region becoming the cauda equina or
horses tail
• There are sensory, motor nerves and
parasympathetic nerves
• The latter supply the bladder (Cf later)
The lumbar and sacral nerve plexuses
• The lumbar plexus is formed from the ventral rami of
the L1-L4 nerves
• It provides motor supply and sensation to the anterior
and medial aspects of the leg
• It also innervates the abdominal wall and pelvic region
• The sacral plexus is formed from a branch of L4 and
the L5-S3 ventral rami
• Provides motor and sensory supply to the posterior
thigh, most of the lower leg, the entire foot and part
of the pelvis
• Note the inguinal ligament – the femoral artery and
femoral nerve pass under the ligament close to the hip
joint
Range of movement lumbar spine
A – Side bending 20 degrees
B – Flexion 50 degrees Extension 15 degrees
C – Rotation 5 degrees
Movement of the sacrum and ilia
• Stability of the sacroiliac joints is very important as these
joints support a large proportion of the weight of the head,
arms and trunk in standing
• Weight is transmitted through the 5th lumbar vertebra and
disc to the first sacral segment
• The sacroiliac ligaments form the main bond which keeps the
sacrum and ilia together
• The sacroiliac joints permit a small amount of movement.
The degree is individual and less in men than women
• When the lumbar spine extends the base of the sacrum nods
forwards termed nutation
• When the lumbar spine flexes the sacrum leans backwards
termed counternutation
• If the hip is flexed up towards the chest the ilia posteriorly
rotate
• As the hip extends the ilia rotate forwards
Movement at the symphysis pubis
• When standing on one leg there is a small amount of
upwards glide on the standing leg side
• As the sacrum is driven down between the ilia in standing
the pubic bones are subjected to a distraction or
separation force
• The stability of the pelvic ring depends on the shape of
the articular surfaces – ridges and hollows fitting together
• The wedge shape of the sacrum
• The ligaments associated with the sacroiliac joints are
some of the strongest in the body and become tight
during sacral nutation
• The abdominals, pelvic floor, lumbar multifidus and the
diaphragm also provide stability
• Also gluteus maximus, latissimus dorsi; there are other
combinations of muscles which provide support
• The erector spinae form the largest group of
back extensors
• The most lateral group, iliocostalis, attaches
to the ribs
• Longissimus attaches to the transverse
processes of the lumbar spine
• Semispinalis, multifidus, rotatores,
interspinales and intertransversarii lie deep
to erector spinae
• The extensor muscles extend the lumbar
spine
• They also act eccentrically – paying out to
control lumbar flexion
• Multifidus - a deep intersegmental muscle
is important in controlling intersegmental
flexion
The abdominal muscles
• Rectus – most superficial – from pubic crest +
symphysis to costal cartilages 5, 6, 7 ribs and
xiphoid of sternum
• Flexes the lumbar spine moving the thorax
towards the pelvis
• External oblique 5th to 12th ribs
• To aponeurosis connecting with the linea alba,
iliac crest and pubic tubercle
• Fibres run down and medially
• Acting bilaterally flexes spine, R ext oblique acting
with L internal oblique rotates the thorax left
• Internal oblique – several sets of fibres, from
inguinal ligament, iliac crest, pubis, linea alba, 10
11 and 12th ribs
• The lower fibres compress and support the
abdominal viscera, upper fibres flex the spine, the
lateral fibres laterally flex the spine
Transverse abdominis
• Transverse abdominis is the deepest of the abdominal
muscles
• It arises from the cartilages of the lower 6 ribs
interdigitating with the diaphragm
• It also arises from the iliac crest and inguinal ligament
• It inserts in to the linea alba
• The fibres run in a transverse or horizontal direction
• The muscle acts like a girdle to compress the abdominal
contents
• The diaphragm, transverse abdominals and pelvic floor
muscles acting together raise intra-abdominal pressure (Cf
later)
Quadratus lumborum and Psoas major
• Quadratus lumborum – from iliolumbar ligament, iliac crest
and sometimes transverse processes of L5-3
• 12th rib, transverse processes of upper 4 lumbar vertebra
• Assists extension, laterally flexes the spine
• Bilaterally, acting with the diaphragm, it fixes the last 2 ribs in
deep inspiration
• Psoas major – ventral surfaces, transverse processes, sides of
vertebral bodies and discs T12 to L5 to lesser trochanter of
the femur
• With the lumbar spine fixed iliopsoas flexes the hip
• With the hip fixed, acting bilaterally, the psoas major
increases the lumbar lordosis
• Acting unilaterally it side flexes the trunk to the same side
Response of the nucleus pulposus to different
spinal positions
• With the spine in a neutral position the disc is
subjected to compressive forces
• In extension the nucleus migrates anteriorly, forces
pass through the posterior disc and the
intervertebral joints
• In flexion the nucleus migrates posteriorly, the
posterior fibres of the annulus and posterior
longitudinal ligament become taut
• The space in the intervertebral foramen is increased
• Compressive forces in the facet joint are reduced
• A flat back posture encourages posterior migration
of the nucleus pulposus (Cf later)
The role of abdominal muscles in reducing
intradiscal pressure
• Contraction of transverse abdominals with the diaphragm
and pelvic floor increases intra-abdominal pressure
• This reduces the lumbar lordosis and dissipates downward
forces from the weight of the body passing through the
vertebral column
• This mechanism is important when lifting to reduce the
forces on the disc and facet joints
Fast twitch and slow twitch muscle fibres
• Red slow twitch type I muscle fibres – endurance fibres, low level
contraction, requires oxygen therefore a good blood supply to produce
energy for contraction. Powered by fat, carbohydrate
• Found in greater concentration in postural muscles such as the transverse
abdominis
• White fast twitch type IIa and IIb muscle fibres – sprinting, short action time,
uses anaerobic energy system. Powered by glycogen
Conditions affecting the lumbar spine
• Nonspecific back pain
• Disc degeneration – disc prolapse
• OA facet joint
• Radiculopathy
• Spinal stenosis
• Spondylolysis and spondylolisthesis
Some facts and figures
• Up to 84% of us will experience back pain at some time in our lives.
35-55 most common age group
• Less than 15% of back pain can be related to a specific problem with
the back
• Research shows that 77% - 90% of back pain gets better within 6
weeks
• 23% of non-specific back pain lasts longer than 12 weeks
• 11-12% of the population are disabled by back pain
• Human beings have always had back pain, it is no more common and
no more severe, it is the experience which has changed
Assessment
• Distribution of symptoms
• Aggravating and easing factors
• History of the condition, previous history
• Medical history – screening for ‘red flags’ – infection, primary or
secondary cancers, bone disorders such as osteoporosis,
inflammatory diseases such as ankylosing spondylitis, infection – TB,
diseases outside the spine – dissecting abdominal aortic aneurysm,
kidney stones
• Bladder +/- bowel dysfunction, retention, incontinence, numbness
over the perineum
Examination
• Posture – spine, pelvis
• Lumbar spine movements and the effect on pain
• Neurological examination for leg pain +/- pins and needles +/numbness – sensation, muscle strength, reflexes
• Straight leg raise to examine the response to movement of the sciatic
nerve
• Prone knee bend to examine the response of the femoral nerve
• Palpation to identify level of dysfunction
• Core stability – function of abdominal muscles, multifidus, gluteal
muscles
• The ankle jerk tests the conductivity of the S1
nerve root
• If the nerve is compressed the reflex will be
depressed or reduced
• Straight leg raising tests the mobility of the
sciatic nerve
• If the nerve is compressed or irritated the
degree of SLR will be reduced
• Dorsiflexion of the foot increases tension along
the nerve and is a refinement to the test
• The knee jerk reflex tests the function of the L3
nerve
• If the nerve is compressed the reflex will be
depressed
• Prone knee bending with the patient in prone
the knee is gently flexed
• The range of movement and pain provocation
tests the mobility of the femoral nerve
What causes back pain?
• Usually there is not a specific condition underlying back pain
• Nothing shows up on tests or is permanently damaged
• It is termed simple or non-specific back pain
Reasons for getting back pain
• Sitting or bending for long periods of time
• Poor posture
• Lifting, carrying or pushing loads which are too heavy, doing it the
wrong way, not having strong enough muscles
• Tripping or falling
• Pregnancy
• Being overweight
• Stress or anxiety
How can I get rid of back pain?
• For back pain only:
• Rest for 1or 2 days only, longer makes no difference, it only weakens
the supporting muscles of the spine
• NSAIDs if there is no reason why you shouldn’t. Paracetamol has
been found to have no effect on back pain
• If you need analgesia low dose opioids such as codeine for a short
time only
• Use ice packs or heat, whichever helps most
• Start to move your back as soon as possible
Mobility and core stability exercises
• Arching and hollowing on all fours
• Rocking backwards towards heels,
forwards towards hands
• Transverse abdominal activation – suck
lower tummy in. Keep breathing
normally. Hold for 10 seconds, repeat 10
times
• Knee rolling side to side. As far
as is comfortable
• Hip hitching – lie on back, legs
straight, stretch one leg down,
hitch the other leg up to tilt the
pelvis upwards on that side
• Progress abdominal exercises lying on back, hollowing
tummy and holding
• Slide heel towards bottom of bed without pelvic
movement
• Let bent knee move out to the side without pelvic
movement
• Lie on tummy – hollow tummy and squeeze
buttocks together at the same time
• Hold at 30% effort for 10 times 10 seconds
• If unable to perform try lying over a pillow
• Progress to contracting tummy and bottom
muscles and flexing knee without back
hollowing
• A Pilates class can be very helpful once the
basic exercises can be completed without
loss of spinal and pelvic stability
How can I prevent it happening again?
• Improve your posture
• Lift correctly
• Lose weight to reduce the stresses on your spine
• Do regular exercises to keep your spine flexible
• Do specific tummy muscle exercises to support your spine – NOT SIT
UPS
• Keep yourself generally fit
Correct lifting
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Assess environment
Correct clothing and foot wear
Test the load
Bend knees and get as close to load as possible
Hold the load as close in to body as you can
Pull in tummy muscles
Push using legs to stand
If you think it is too heavy for you ask someone
else to lift the load if possible
• You need to be fit to lift – good tummy muscles,
strong quadriceps
Age changes affecting the disc
• The nucleus pulposus has reduced water content due
to changes in proteoglycans
• Annulus fibrosis made of concentric rings called
lamellae, adjacent rings fibres orientated in opposite
direction
• Annulus surrounds and contains the nucleus
• With loss of water content tears appear in the
annulus allowing the nucleus to migrate, usually
posteriorly
• There is also loss of disc height
Nerve supply to the outer layers of the disc
• The outer layers of the annulus of the disc are supplied by the
sinuvertebral nerve
• It also supplies the posterior longitudinal ligament, blood
vessels in the spinal canal, the anterior covering of the spinal
cord, the outer sleeves of the spinal nerves, the posterior
periosteum of the vertebra
• Pain can therefore be felt from all of these structures – hence
the intense pain from sciatica
The consequences of reduced disc height
• Reduced disc height leads to new bone
formation around the edges of the
vertebral body
• The posterior annulus can bulge like a flat
tyre which can reduce the space for the
nerve in the intervertebral foramen
• Reduced disc height also causes the
anterior, posterior and ligamentum flavum
to slacken allowing more translator
movement to occur
• The facet joints are subjected to more
compression forces which can lead to
osteoarthritis
Facet joint degeneration
• OA of the facet joint leads to formation of bony spurs
which can irritate or compress the spinal nerve
• If the S1 nerve is affected this causes pain down the
back of the leg, weakness of the calf muscle, reduced
ankle jerk
• In the early stages there may be low back pain, +/leg pain with stiffness of the lumbar spine
• At this stage, manual therapy, manipulation to
increase spinal movement may help
• This is combined with mobility exercises, postural
correction
• Core stability exercises to off load the spine
• If pain and disability is considerable further
investigations such as an MRI scan may be indicated
MRI scan showing facet joint degeneration
• If the facet joint is thought to be the main source of pain and
surgery is not indicated
• Facet joint denervation of the medial nerve branches to the
joint may be offered
• This can be very effective in treating the pain for a year or more
Radiofrequency denervation of the facet joint
Pathologies: Disc Protrusion
• As described earlier the annulus of the disc can bulge due to
reduced water content
• The annulus can also tear allowing the nucleus to migrate
backwards towards the central canal or laterally towards the
intervertebral canal
• A central prolapse can compress the cauda equina giving
symptoms of bladder retention, incontinence of bladder or
bowel
• Numbness over the perineum is also a symptom of
compression
• It is important to seek urgent medical attention as prolonged
compression of these nerves can cause permanent damage
to the nerves with permanent bladder and or bowel
dysfunction
• A more lateral disc bulge causes spinal nerve root
compression
• Occasionally a disc fragment can become extruded causing
variable symptoms as it is free to move within the spinal
canal
Management of an annular disc bulge
• In younger patients where facet joint OA is not significant back
extension exercises can be helpful to encourage the nucleus to
migrate anteriorly away from the spinal canal
• In the early stages lying on the tummy and gently pushing up as
far as is comfortable and repeating this 10 times every hour can
dramatically reduce the pain
• Avoiding sitting which increases intradiscal pressure is
important
• Core stability exercises should be started early again to offload
the disc
• If there are significant neurological changes early referral for
further investigations and possible surgical intervention is
indicated
• Microdiscectomy
• If there is significant neurological involvement
surgery should be considered early in the episode
• In some patients conservative management may
resolve the problem but where significant pain and
disability remains referral for an MRI should be
considered
• Where the MRI findings match the clinical
presentation an epidural may be considered or
surgery such as microdiscectomy can be very
effective
• Surgical intervention is the option of choice for about
2% of all cases of back and leg pain
• Post operative rehabilitation is required to increase
spinal mobility, ensure good nerve mobility, retrain
core stability muscles, encourage return to normal
fitness
Spinal stenosis
• Narrowing of the central canal due to enlargement of the
facet joints, bulging disc and thickening of the ligamentum
flavum
• Age 50s onwards, pain usually in both legs made worse
with standing or walking, reduced by bending forwards
• Leg pain on walking can be due to reduced circulation
therefore it is important to examine the peripheral
circulation to the legs. Doppler can be a useful test for this
• In the early stages techniques to open the spinal canal can
be helpful, flexion exercises, joint mobilisation into flexion,
sitting in a more flexed position, lying on side with knees
bent at night
• If symptoms persist and are sufficiently disabling to
consider surgery referral for MRI scan
• Possible decompression and fusion
Spinal fusion
• Discussion with surgeon re possible risks and
benefits of surgery
• Can be a good treatment option if only 1 or 2
spinal levels affected
• Stenosis found at multiple levels or significant
surgical risk may be better to consider using a
motorised scooter to increase mobility
Spinal instability
• Can be in young people with a genetic fault in the bone - swimmers, gymnasts,
cricketers
• Repeated episodes of severe back and leg pain associated with trivial incidents
• In older people worn discs can cause small movements of the bony structures
which are painful
• Treatment – strengthen tummy muscles to support the back, correct over
hollowed back posture
• MRI scan
• Possible spinal fusion
Pathologies: Spondylolisthesis
Finally
• Thank you for staying the course
• Thank you for your participation and very helpful comments
• Helpful website www.patient.info. The professional tab gives in depth
information. There are also links to helpful patient leaflets
• Happy Christmas and here's to 2017 with fewer aches and pains!!