Dissa_s Spine Lecture

8/10/2019 Dissa_s Spine Lecture

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Griffith School of Medicine

Anatomy of the SpineDr. Lakal Dissabandara

Presented on 13/04/2010


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Functions of the Spine

Support upright position of the trunk and the

cranium

Transmission of weight of the trunk to the

inferior extremities/shock absorption

Provides articular surfaces for the attachment

of the ribs/muscles

Protection of the spinal cord

Haemopoisis

Parts of Vertebra


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Types of Vertebrae

Cervical transverse foramina

for the vertebral artery, bifid

spine

Thoracic Articular demi

facets for ribs on the body and

transverse processes

Lumbar large vertebral

bodies for wt bearing, straight

spine

Inter-vertebral Joints

Two types Anterior IV joint (Between the vertebral bodies

Symphyses) allow slight movement in all directions Reinforced by the anterior and posterior longitudinal

ligaments Weight bearing and shock absorption

Initially nucleus pulposus absorb the force andthen transmitted to annulus

Posterior IV joint - Facet joints (Zygapophyseal)

Synovial Normal synovial joint structureAllow gliding movements

Thoracic spine has joints with ribs


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Inter Vertebral Disc

Parts

Annulus fibrosus fibrocartilageconsisting of concentric lamellae ofCollagen (65% water)

Outer margin is tightly attachedto the vertebra

Nucleus Pulposus jeatinousProteoglycans and some Collagen(80% water)

Secreted by cells in the annulus

Proteoglycans responsible forthe strength and pliability

End plates

A hyaline cartilageAttached to the disc tightly, and

loosely to the vertebral body

Important for vertical growth ofIVD.

Annulus facilitate torsional movements

IVD s account for 25% of height of spine

IVD s are also supported by ALL and PLL of spine.


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Ligaments

Anterior longitudinal lig.

Posterior longitudinal lig.

Ligamentum flavum lig.

Supraspinous lig. Ligamentum Nuchae in Cervicalspine

Interspinous lig.

Intertransverse lig.

Facet capsular lig.

Supports

IVD as well

http://www.hkeducationcenter.com/courses/OEC_Previews/hf-ft101ue_preview/images/Fig_28.png


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Curves of the spine

Primary curvature At birth the spine is concave

forwards

Secondary curvatures

With lifting of head forward convexity of cervical

spine

With standing forward convexity of lumbar spine

2ry curvatures are primarily due to the shape of the

IVD s.

Curvatures increase the shock absorbing capacity and facilitate stability &

equilibrium of spine

(Resistance of a system of column = number of curvature2+ 1)

http://www.emory.edu/back.html

Kyphosis

Increased forward

concavity

Scoliosis

Sideward deviation

Increased Lordosis

Increased forward

Convexity of L spine

Normal Curvatures Abnormal Curvatures

1ry forward

concavity

2ry cervicalforward convexity

2ry Lumbar

forwardconvexity


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Movements

AIVJ restricts movements & the ligaments restrict movements

Cervical

Very mobile tall IVD s, smaller bodies, morphology of C1 &C2

Flexion, extension, lateral flexion, rotation

Thoracic

Rotation

Other movements are restricted

Presence of ribs

IVD s are thin

Long spines

Orientation of facets

Lumbar

Flexion & extension

Direction of articular facets makes rotation difficult

Flexion/Extension Yes

Rotation No

Transverse Lig

Alar Lig


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Lumbar vertebra

`

`Thoracic vertebra

Articular facets more

in a sagittal plain

Limit Rotation

Articular facets more in

a coronal plain

Rotation possible

ExtrinsicBack

Muscles

Trapezius

Rhomboids major

Rhomboids minor

Levator scapulae

Latissimus dorsi

Back Muscles

Prevertebral muscles

Scalenes - Cervical region

Psoas/Quadratus lumborum

Anterior abdominal muscles

Muscles moving vertebral column

Superficial

Erector spinae

- Illiocostalis

- Longissimus

- Spinalis

Splenius

(Vertical)

Intermediate

(Transversospin

ales)

Rotators

Multifidus

Semispinales

Deep

Interspinales

Intertransversales

Intrinsic Back Muscles


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Superficial Back Muscles

Trapezius

Latissimus dorsi

Rhomoboids major

Rhomoboids minor

Thoracolumbar fascia

Serratus

posterior

superior

/inferior

How are these

muscles innervated?

Intrinsic Back Muscles


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Back Pain

Mechanical due to injury of constituents of spine(bones, ligaments or muscles)

Usually localized

SLRT Negative**** ????

Inflammatory

IVD prolapse/narrowing of IV foramen

Can cause nerve root compression

Radiating pain

+ ve SLRT/femoral stretch test Neurological signs

Sensory Innervation of Vertebral column

All the ligaments,

facet joints, IVD

are richly

innervated.

Sympathetic

visceral sensory

fibres also

important for the

innervation -

Annulus

Back pain may occur due to pathology of any of these structures or due to

referred pain from viscera pancreas, kidneys


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Straight Leg Raising Test

Facet joints

SI joint

Muscle tightness

Hip joint pain

Roots become

increasingly tensed

Start applying tension

on Roots

No further deformation

of roots beyond this

point

No tension on roots


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Pain may be exacerbated by movements that transmit pressure to the nerve root

through the subarachnoid space (eg, moving the spine, coughing, sneezing, doing the

Valsalva maneuver). Lesions of the cauda equina, which affect multiple lumbar and

sacral roots, cause radicular symptoms in both legs and may impair sphincter and

sexual function.


Femoral stretch test

Tests irritation of L2,3,4

roots

Patient feels pain on

anterior thigh


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IV Disc Prolapse

If the pressure on nucleus pulposus cannot be resistedby the anulus, it will give away, releasing the nucleusfree impinge on nerve roots

3 stages BulgingProtrusionSequestration

Common at regional junctions where more movablespine and relatively less mobile spine meets

Cervico thoracic

Lumbosacral

Sensory, Motor, Reflex testing would help to localizethe lesion

Compressed nerve root can be made to stretch bydoing SLRT/FST which elicit pain

Anatomy of IV Disc

L4-5

Exiting root L4

Traversing root L5

Nerve roots of thecal sac

PLL

Lamina

Think about thedermatomes, myotomes

and otherimportant

structures (eg.sphinctors)

innervated by these roots.Chirogeek.com


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Bulging of the disc

For disc herniation to occur, the disc must degenerate first. Drying of theannulus makes it brittle and unable to retain the bulging nucleus.

Note the PLL (Blue), redened nerve roots supplying annulus (one cause

of back pain).

Chirogeek.com

Protrusion

The nuclear material is pressing on PLL and its bulging out now

(Still connected to main mass of NP). Note the resultant Pressure

on L4, L5, S1 (become inflamed).

Extrusion


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A portion of nuclear material (blue star) detached from the main mass.

Now more compression on traversing root (white star) and exiting root

(green star).

Also note compression of thecal sac by sequestered nuclear material.

Which nerve roots can be compressed by this? (refer to the fig 1)

What would be the effect?

Sequestration

Chirogeek.com

Distribution of radicular painS1

L5

L4

Note the red areas

Chirogeek.com


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Thoracolumbar fascia

Functions Stabilization ofspine

Help transfer ofload throughdifferent musclegroups

Attachment ofmuscles

Limit flexion

Surface Anatomy

C7

T3

T8

L4-5

Pos sup iliac

spine S2

Sacral Hiatus

Posterior Sup Iliac spine and sacral hiatus form and equilateral triangle

Surface Anatomy


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Dissa_s Spine Lecture