vertebral column for the lecture final exam. the axial skeleton skull sternum vertebrae – 7...

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

Intervertebral disc

Superior articular process Spinal cord

Pedicle

Body of vertebra

Spinous process

Inferior articular process Lamina

Spinal nerve

Intervertebral disc

Transverse process


Transverse costal facet (for tubercle of rib) Superior costal facet

(for head of rib)

Body of vertebra

Head of rib

Intervertebral disc

Tubercle of rib

Neck of rib

Shaft Sternum

Angleof rib

Cross-sectionof rib Costal groove

(b) Vertebral and sternal articulations of a typical true rib

Costal cartilage


Spinous processArticular faceton tubercle of rib

Shaft

Ligaments

Neck of rib

Head of rib Body ofthoracicvertebra

Transversecostal facet(for tubercleof rib)

Superior costal facet(for head of rib)

(c) Superior view of the articulation between a rib and athoracic vertebra

Atlas (1st cervical vertebra)

Axis (2nd cervical vertebra)

Typical cervical vertebra

Typical lumbar vertebra Typical thoracic vertebra


Cervical curvature(concave)

7 vertebrae, C1 – C7

Thoracic curvature(convex)

12 vertebrae,T1 – T12

Lumbarcurvature(concave)

5 vertebrae, L1 – L5

Sacralcurvature

(convex) 5 fusedvertebrae sacrum

Coccyx4 fused vertebraeAnterior view Right lateral view

C1

T1

2

3

4

5

6

7

8

9

10

11

12

L1

2

3

4

5

2

3

4

567

SpinousprocessTransverseprocesses

Intervertebraldiscs

Intervertebralforamen

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.


Supraspinous ligamentIntervertebraldisc

Anteriorlongitudinalligament

Intervertebral foramen

Posterior longitudinalligament

Anulus fibrosus

Nucleus pulposus

Sectioned bodyof vertebra

Transverse process

Sectionedspinous process

Ligamentum flavum

Interspinousligament

Inferior articular process

(a) Median section of three vertebrae, illustrating the compositionof the discs and the ligaments

Ligaments of the vertebral column


Posterior longitudinalligament

Anterior longitudinalligament

Body of a vertebra

Intervertebral disc

(b) Anterior view of part of the spinal column

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 nerve root

Anulus fibrosusof disc

Herniated portionof disc

Nucleuspulposusof disc

Spinal cord

(c) Superior view of a herniated intervertebral disc

Transverseprocess


Nucleus pulposus of intact disc

(d) MRI of lumbar region of vertebral column in sagittal section showing normal and herniated discs

Herniated nucleuspulposus


Dens of axis

Transverse ligamentof atlasC1 (atlas)

C2 (axis)

C3

Bifid spinousprocess

Transverse processes

C7 (vertebraprominens)

(a) Cervical vertebrae

Inferior articularprocess


The sacrum and coccyx.

Body offirstsacralvertebra

Transverse ridges (sites of vertebralfusion)

Coccyx Coccyx

AnteriorsacralforaminaApex

Posteriorsacralforamina

Mediansacralcrest

Sacral promontorySacralcanal

Sacralhiatus

BodyFacet of superiorarticular process

Lateralsacralcrest

Auricularsurface

Ala

(a) Anterior view (b) Posterior view


Intercostalspaces

True ribs(1–7

Falseribs(8–12)

Jugular notchClavicular notch

Manubrium

Sternal angleBody

XiphisternaljointXiphoidprocess

L1

VertebraFloating ribs (11, 12)

(a) Skeleton of the thoracic cage, anterior view

Sternum

Costal cartilageCostal margin


XiphisternalXiphisternaljoint

Heart

Sternal angle

Jugular notch

(b) Midsagittal section through the thorax, showingthe relationship of surface anatomical landmarksof the thorax to the vertebral column

T2

T4

T3

T9

Biceps brachii

Pectoralis major

Deltoid

Trapezius

Sternocleidomastoid

Subclavius

External intercostals

Internal intercostals

Serratus anterior

Pectoralis minor

Teres major

Latissimus dorsi

Triceps brachii

Coracobrachialis

Biceps brachii (long head)

Biceps brachii (short head)

Internal obilque

Tensor fasciae latae

Iliopsoas

Rectus femoris

Adductor longus

Rectus abdominis

Sartorius

Pectineus

External obilque

Latissimus dorsi

Deltoid

Rhomboid major

Trapezius

Rhomboid minor

Epicranius (occipital belly)

Splenius capitis

Triceps brachii (long head)

Serratus anterior

Teres major

Teres minor

Infraspinatus

Supraspinatus

Triceps brachii (lateral head)

Levator scapulae

Latissimus dorsi

Trapezius

Serratus anterior

External intercostals

Internal oblique

Spinalis

Iliocostalis

Longissimus

External oblique

Sternocleidomastoid

Orbicularis oculi

Pectoralis minor

Rectus abdominis

Sternohyoid

Latissimus dorsi

Teres major

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.

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 BraceThis 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-mid-back (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

Body of vertebra

Spinous process

Inferior articular process Lamina

Spinal nerve

Intervertebral disc

Transverse process

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!

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• 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

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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!

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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.

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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.

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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

Lying down: 25 psi

Laying on your side: 75 psi

Standing: 100 psi

Sitting: 140 psi

Bending forward: 150 psi

Leg lifts: 180 psi

DISC PRESSURE IS MEASURED IN POUNDS PER SQUARE INCH

Your body will respond and adapt to these positions.

Looking at computers all day

Putting phones between the ear and shoulder

Lifting incorrectly

Weightlifters

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 + 150 = 180 lbs

= 30 lbs

100 + 150 = 250 lbsHolding box away from body:

Bending over at the waist,

without bending the

knees

= 150 lbs

PROPER SITTING

Nothing in back pockets

Put a pillow behind your low back

Sit up straightDon’t slouch

IMPROPER SITTING

Looking down all day compresses the discs in the neck

Sitting with the computer too low

Sitting on your foot

Phone between ear and shoulder

PROPER WRIST POSITION

Special devices keep your wrists straight while you type.

Backaches

Neck Aches

Headaches

Using the computer with your wrists bent causes problems:

Carpel Tunnel Syndrome

PROPER DESK WORK STATION

Phone headset for hands-free use

Keyboard pad

under your wrists

Computer at eye leveland 18-25” away from your face

The front of the chair should drop off

Adjustable seat: Feet flat to the floorOr a foot rest under the feet

Chair with good lumbar support or$10 lumbar pillow

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

vertebral column for the lecture final exam. the axial skeleton skull sternum vertebrae – 7...

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