Transcript B. Vertebral Column

Vertebral Column
For the Lecture Final Exam
The Axial Skeleton
• Skull
• Sternum
• Vertebrae
– 7 Cervical
– 12 thoracic
– 5 lumbar
– 5 sacral
– 5 fused coccygeal
• Ribs
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Intervertebral disc
Superior articular process
Spinal cord
Pedicle
Spinous process
Body of vertebra
Transverse process
Intervertebral disc
Spinal nerve
Inferior articular process
Lamina
Transverse costal facet
(for tubercle of rib)
Angle
of rib
Superior costal facet
(for head of rib)
Body of vertebra
Head of rib
Intervertebral disc
Neck of rib
Tubercle of rib
Shaft
Crosssection
of rib
Costal groove
Sternum
Costal cartilage
(b) Vertebral and sternal articulations of a typical true rib
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Articular facet
on tubercle of rib
Spinous process
Shaft
Ligaments
Neck of rib
Head of rib
Superior costal facet
(for head of rib)
Transverse
costal facet
(for tubercle
of rib)
Body of
thoracic
vertebra
(c) Superior view of the articulation between a rib and a
thoracic vertebra
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Axis (2nd cervical vertebra)
Atlas (1st cervical vertebra)
Typical cervical vertebra
Typical thoracic vertebra
Typical lumbar vertebra
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
Anterior view
Cervical curvature
(concave)
7 vertebrae, C1 – C7
Spinous
process
Transverse
processes
Thoracic
curvature
(convex)
12 vertebrae,
T1 – T12
Intervertebral
discs
Intervertebral
foramen
Lumbar
curvature
(concave)
5 vertebrae, L1 – L5
Sacral
curvature
(convex) 5 fused
vertebrae sacrum
Coccyx
4 fused vertebrae
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Right lateral view
Intervertebral
discs
The intervertebral discs are composed
of an outer layer that is thick and
fibrous, called the anulus fibrosus,
and a spongy inner layer called the
nucleus pulposus.
Both layers are composed of water,
collagen, and proteoglycans (PGs),
which are proteins + sugar.
The nucleus pulposis is mostly water
and PGs, and acts like a water balloon.
When compressed, it stretches in all
directions.
The anulus fibrosis is mostly water and
collagen. It holds the nucleus pulposis
in place so it does not pop.
Ligaments of the vertebral column
Supraspinous ligament
Transverse process
Intervertebral
disc
Anterior
longitudinal
ligament
Sectioned
spinous process
Ligamentum flavum
Interspinous
ligament
Inferior articular process
Intervertebral foramen
Posterior longitudinal
ligament
Anulus fibrosus
Nucleus pulposus
Sectioned body
of vertebra
(a) Median section of three vertebrae, illustrating the composition
of the discs and the ligaments
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Posterior longitudinal
ligament
Anterior longitudinal
ligament
Body of a vertebra
Intervertebral disc
(b) Anterior view of part of the spinal column
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Herniated Intervertebral Discs
• The narrow PLL in the lumbar region does not
provide much support to the intervertebral
discs, which is one of the reasons that
posterolateral herniations are more common
in the lumbar region.
• Increased pain in the flexed position is
common in a PLL defect with subsequent
herniation.
Vertebral spinous process
(posterior aspect of vertebra)
Spinal cord
Spinal nerve root
Transverse
process
Herniated portion
of disc
Anulus fibrosus
of disc
Nucleus
pulposus
of disc
(c) Superior view of a herniated intervertebral disc
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Nucleus pulposus
of intact disc
Herniated nucleus
pulposus
(d) MRI of lumbar region of vertebral column in sagittal
section showing normal and herniated discs
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Dens of axis
Transverse ligament
of atlas
C1 (atlas)
C2 (axis)
C3
Inferior articular
process
Bifid spinous
process
Transverse processes
C7 (vertebra
prominens)
(a) Cervical vertebrae
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The sacrum and coccyx.
Body
Sacral promontory
Ala
Sacral
canal
Body of
first
sacral
vertebra
Facet of superior
articular process
Auricular
surface
Transverse
ridges (sites
of vertebral
fusion)
Apex
Median
sacral
crest
Anterior
Posterior
sacral
sacral
foramina
foramina
Coccyx
(a) Anterior view
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Coccyx
(b) Posterior view
Lateral
sacral
crest
Sacral
hiatus
Jugular notch
Clavicular notch
Manubrium
Sternal angle
Body
Xiphisternal
joint
Xiphoid
process
True
ribs
(1–7
False
ribs
(8–12)
Intercostal
spaces
L1
Vertebra
Floating ribs (11, 12)
(a) Skeleton of the thoracic cage, anterior view
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Costal cartilage
Costal margin
Sternum
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T2
Jugular notch
T3
T4
Sternal angle
Heart
T9
Xiphisternal
joint
(b) Midsagittal section through the thorax, showing
the relationship of surface anatomical landmarks
of the thorax to the vertebral column
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Subclavius
Biceps brachii
(short head)
Biceps brachii (long head)
Sternocleidomastoid
Coracobrachialis
Trapezius
Deltoid
Triceps brachii
Latissimus dorsi
Teres major
Pectoralis major
Pectoralis minor
Serratus anterior
Biceps brachii
Internal intercostals
External intercostals
External obilque
Rectus abdominis
Internal obilque
Tensor fasciae latae
Sartorius
Iliopsoas
Pectineus
Rectus femoris
Adductor longus
Splenius capitis
Levator scapulae
Supraspinatus
Infraspinatus
Teres minor
Triceps brachii (lateral head)
Triceps brachii (long head)
Epicranius (occipital belly)
Rhomboid minor
Trapezius
Rhomboid major
Deltoid
Teres major
Serratus anterior
Latissimus dorsi
Trapezius
Spinalis
Iliocostalis
Longissimus
Serratus anterior
Latissimus dorsi
External intercostals
Internal oblique
External oblique
Orbicularis oculi
Sternohyoid
Sternocleidomastoid
Pectoralis minor
Rectus abdominis
Teres major
Latissimus dorsi
Cervical Plexus
Nerves innervate skin of
neck, back of head and
upper shoulder.
Phrenic nerve
(important for
breathing!) from C3, C4,
C5. Carries afferent
and efferent fibers to the
respiratory diaphragm.
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Patient Case
• Mary complained of not being able to breathe easily
when playing tennis. She does not have asthma.
• Orthopedic consultation showed that Mary has a
midthoracic scoliotic curve of 40 degrees.
• It is likely that the scoliosis is accompanied by
rotation of those vertebrae, which might decrease
her pulmonary reserve.
• This might be a contributing factor in her shortness
of breath when she tries to play tennis.
Boston Scoliosis Brace
This is a firmly fitting pelvic girdle
that extends upward to apply
forces to the ribs in a way that
limits the exacerbation of the
scoliotic curvature.
While worn, this device
decreases ability to breathe by
15-20%, so it cannot be worn
during sport activities.
Surgery may be necessary if the
brace does not limit the
progression sufficiently.
Patient Case
• Joe is a 33 year old construction worker who,
for several months, has been experiencing
moderate to severe low back pain which
radiates into his right buttock.
• He has pain with carrying, and all lifting
activities. He can relieve the pain somewhat
when sitting or laying down, but has only
been able to work for 4 hours at a time.
• His history includes several episodes of low
back pain that were severe but resolved in a
few days.
Sciatica
• Joe might have sciatica, except that his pain is better when
sitting.
• Sciatica refers to pain, weakness, numbness, or tingling in the
leg. It is caused by injury to or pressure on the sciatic nerve.
Sciatica is a symptom of another medical problem, not a
medical condition on its own.
• Common causes of sciatica include:
• Herniated intervertebral disc
– Treatment is oral or injected anti-inflammatory meds or surgery
• Piriformis syndrome
– sciatic pain due to contracture of the piriformis muscle in the buttocks
– Treatment is stretching exercises (lay supine and pull one knee to the
opposite shoulder)
Herniated Intervertebral Discs
• These discs may move out of place (herniate) or break open
(rupture) from injury or strain. When this happens, there may
be pressure on the spinal nerves. This can lead to pain,
numbness, or weakness.
• The lower back (lumbar area) of the spine is the most
common area for a slipped disc. The neck (cervical) discs are
affected a small percentage of the time. The upper-to-midback (thoracic) discs are rarely involved.
• Radiculopathy is any disease that affects the spinal nerve
roots. A herniated disc is one cause of radiculopathy.
Sciatica
• The pain often starts slowly.
• It may get worse:
– After standing or sitting
– At night
– When sneezing, coughing, or laughing
– When bending backwards or walking more than a
few yards
DIAGNOSTIC TESTS for Sciatica
• Electomyelogram (EMG) may be done to determine the exact
nerve root that is involved.
• Nerve conduction velocity test may also be done.
• Spine MRI or spine CT will show that the herniated disc is
pressing on the spinal canal.
• Spine x-ray may be done to rule out other causes of back or
neck pain. However, it is not possible to diagnose a herniated
disc by a spine x-ray alone.
Spondylolisthesis
• This is a possible source
of Joe’s pain. In this
disorder, pain is not
usually present in the
sitting position.
• Flexion activities such as
sitting decreases the
anterior shear forces on
the lumbar spine.
• Extension activities are
the most painful with
this disorder.
Patient Case
• Joe’s pain could also be caused by damage to the
posterior aspect of the anulus fibrosus in the lumbar
discs. The overloading of forces there can also cause
fluid loss in the disc, resulting in loss in disc height.
• The lumbar discs might even be herniated.
• There are no posterolateral anular ligaments in the
lumbar region, so flexion with rotation can damage
the discs there.
• Damage in the cervical discs is unlikely because
flexion and rotation in the cervical region will not
damage the anulus fibrosus there.
Patient Case
• The shape of an individual’s lumbar joints may
be a factor that predisposes some people to
have injury, but not others.
• If the superior and inferior articular facets in
the lumbar region are oriented entirely in the
sagittal plane, they offer little bony resistance
to anterior sheer forces.
Patient Case
• Joe’s daily activities at work causes large
anterior sheer forces.
• That puts stress on the iliolumbar ligaments,
the posterior anulus fibrosus, the PLL, and the
joint capsules.
• It is even more likely to be the problem if his
superior and inferior articular facets are
oriented in the sagittal plane.
• Some or all of these structures might have
failed. They are all innervated and may be the
source of pain.
Superior articular process
Spinal cord
Pedicle
Spinous process
Body of vertebra
Transverse process
Intervertebral disc
Spinal nerve
Inferior articular process
Lamina
Patient Case
• Joe needs exercises to maximize the ability of
the deep erector spinae muscles to control the
excessive anterior shear forces.
• Right now, he needs to minimize activities that
cause the anterior shear forces to decrease his
symptoms.
• If he cannot change his activities, he could use
a lumbosacral brace to provide proprioceptive
input for positioning and possible protect him
from further injury.
Is the base of your sitting spine
being asked to flex or extend?
• If you are too tall for your seat, sitting in the standard office
chair has you flexing your discs(L4-L5 and L5-S1) to excess
(see middle diagram next slide).
• If you are a short person (possibly with a large abdomen),
sitting in the standard office chair has you extending your
discs (L4-L5 and L5-S1) to excess (see right hand diagram next
slide).
• Add to this the possibility that you are constantly twisting in
your chair to open a file cabinet to your side or to pick up a
phone on the table behind you, and you have a recipe for
back pain disaster!
easyvigour.net.nz
easyvigour.net.nz
• The three directions of force that can injure a
"pre-flexed" intervertebral joint:
• Over flexing of the Lower Spine
• Anterior Shear of the Lower Spine
• Twisting/Side Bend of the Lower Spine
easyvigour.net.nz
Over flexing of the Lower Spine
•
The forward bending subject in the diagram to the right - typically a middle aged man who
spends a lot of time in slumped chair sitting - has his spine bent at the lower lumbar region
(L4-L5, and L5-S1) (and also at the lower thoracic region). The torso of this man has adopted
the same shape as that of a chair sitting man slumped down into his chair. The lowest two
discs are being taken to their flexed extremes. Now ask this man to pick up a heavy carton...
Lumbar herniation and pinched sciatic nerve (or sciatic nerve root to be precise) is a
certainty!
easyvigour.net.nz
Anterior Shear Force on the Lower Spine
• Anterior shear is when a vertebra slips forward on the vertebra (or the
sacrum) immediately below it (diagram of anterior shear, see below). Like
disc herniation, most anterior shear happens at L4-L5 and L5-S1. There is
minimal anterior shear force while sitting, but sitting does train the low
lumbar spine to go easily into flexion. And here is the connection: it takes
as little as one fifth of the anterior shear force to damage the flexed
intervertebral joint as compared with the same joint in neutral. The
habitual chair sitter who carries his "chair sitter" lumbar flexion tendency
with him during a "fall onto the buttock" (see diagram) may thus be up to
five times more likely to sustain damage.
Diagrams illustrating Anterior Shear
Force on the flexed lumbar spine of
a person sustaining a backward fall
onto the buttock. Note: While anterior
shear force can do painful damage to
the flexed lumbar spine, actual visible
anterior slippage on plain x-ray images
is not likely to be seen. You need
fractures or developmental defects in
the vertebra close to the facet
joints (spondylolysis) for anterior
slippage (sponylolisthesis) to occur.
easyvigour.net.nz
Dangerous rotation/side-bending
• Moving your lower back into extremes of rotation or
twisting is especially damaging in terms of disc damage and
pinched sciatic nerve pain. For example: you sit directly in
front of your computer, but you have to reach behind you to
answer your phone; you constantly open a file cabinet to the
left of your desk; people are constantly opening a door to
your right to interrupt you. You are under pressure, and you
are forgetting to maintain a neutral curve in your spine
(similar to your standing curve).... In short you are suffering a
prolonged and damaging onslaught to your spinal health. You
will definitely damage your lumbar discs, with a high
likelihood of disc herniation and sciatic nerve pinching.
easyvigour.net.nz
Note
• Lumbar flexion is not the same as hip flexion.
• You can flex your hips while keeping the spine
straight. This is especially important when
squatting.
• Lumbar flexion causes anterior shear forces,
which are dangerous to the lumbar
intervertebral discs.
Deep Erector Spinae muscles
• Like the levator scapulae in the
cervical region, the deep
erector spinae will become
overworked and painful when
subjected to anterior shear
forces.
• However, therapy should focus
on strengthening instead of
stretching them because they
are the only restraint to the
excessive anterior shear forces,
and stretching may worsen the
symptoms.
• Wear a lumbar brace until these
muscles are strengthened.
Levator Scapula
• Anterior shear forces
(flexion) of the neck,
increases loading on
the levator scapula.
• Stretching as therapy
for this muscle can be
beneficial, since the
anterior shear forces
are restrained by
other structures.
• Exercises that involve strengthening the upper
extremity will help to stabilize the trunk as
well, since they produce tension on the fascia
(connective tissue) that connects those
muscle groups.
• The upper extremity muscles can be
strengthened without producing trunk
movement, so this us good therapy for early
stages of rehabilitation.
Exercises for Low Back Pain
• Exercises to increase the strength of the back extensors are
often performed in the prone position.
• The lowest compression forces in the low back are single-leg
extension while on the hands and knees. Raising an arm and
leg simultaneously increases compression, and might worsen
the condition.
• Sit ups of any kind are also not good for someone with a low
back injury.
GOOD
BAD
The rest of this PPT
is not on any exam
DISC PRESSURE IS MEASURED IN POUNDS PER SQUARE INCH
Lying down: 25 psi
Laying on your side: 75 psi
Standing: 100 psi
Sitting: 140 psi
Bending forward: 150 psi
Leg lifts: 180 psi
Looking at computers all day
Putting phones between
the ear and shoulder
Lifting incorrectly
Weightlifters
Your body will respond and adapt
to these positions.
Proper back support in bed
How do you lift properly?
The knees are bent,
the back is straight,
the buttocks are
tucked in, and the
shoulders are back,
with the weight on the
legs and the buttocks
The “Ready” Position
PROPERLY LIFTING BOX OFF FLOOR
Keep the knees bent,
back straight,
keep the box close to the body,
and lift with the legs.
This keeps a neutral lumbar
spine position, which removes
some strain from the deep
erector spinae and allow them to
control the anterior shear forces.
IMPROPERLY LIFTING BOX OFF FLOOR
= 30 lbs
Bending over
at the waist,
without
bending the
knees
Holding box away from body:
= 150 lbs
30 + 150 = 180 lbs
100 + 150 = 250 lbs
PROPER SITTING
Don’t slouch
Sit up straight
Put a pillow behind your low back
Nothing in back pockets
IMPROPER SITTING
Sitting on your foot
Phone between
ear and shoulder
Sitting with the
computer too low
Looking down all day compresses the discs in the neck
PROPER WRIST POSITION
Using the computer with your wrists bent
causes problems:
Backaches
Headaches
Neck Aches
Carpel Tunnel Syndrome
Special devices keep your wrists straight while you type.
PROPER DESK WORK STATION
Phone headset for hands-free use
Computer at eye level
and 18-25” away from your face
Chair with good lumbar support or
$10 lumbar pillow
Keyboard pad
under your wrists
The front of the chair
should drop off
Adjustable seat: Feet flat to the floor
Or a foot rest under the feet
EXERCISES
TO DO
DURING THE DAY
AT WORK
Turn your head to the left and right
Tilt head to both sides
Roll head in circle
Reach your spine to the ceiling
Pull your shoulders back and forth a
few times
Pull shoulders up and down
Retract the neck
Stretch your arms and hands out in
front of you with fingers interlocked
Turn hands up and down
Wrist stretches
Use a step stool while standing
Arch your back a little
Look around and away
Stretch the legs and feet out
Twirl feet in circle
Don’t reach too far