back and spinal cord

7/24/2019 Back and Spinal Cord

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Clinical Anatomy

Back


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Objectiv

Describe the partsvertebrae and leardistinguishing feateach.

Analyze why flexio

limited in the thorregion and extensimaximum in the luregion.


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Objectives Draw and label the pa

spinal nerve. Recogni

different types of fibenerve carries.

Draw a schematic transection through the smeninges, and verteb

Understand the strucfunction of the dorsalventral spinal nerve rorami


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Objectiv

Describe the Meningeclinical significance ofperform a spinal tap

Recognize why the supmuscles of the back haaction on the vertebra

Recognize the actions muscles of the back overtebral column and possible causes of low


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Overview Back-extends from th

the buttocks

Skin and subcutaneo Superficial layer of m

function is to

Deep layer of muscle

is to Vertebral column

Ribs

Pelvic girdle


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VERTEBRAE

Back


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Vertebrae

How many vertebrae?

How are they arranged?

What happens to the siz

vertebrae?

I-V discs, what is their fu

How many IV discs are t


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Vertebral co

Curvatures of th

column

Cervical

Thoracic

Lumbar

sacral


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Vertebra

Typical features

Vertebral body Vertebral arch

Pedicle

Lamina

Vertebral foramen

Epiphyseal rim

Seven processes:

2TP, 1SP, 2superior aarticular processes


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SUMMARY OF VERTEBRAL CHARACTERSTICS


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VERTEBRAE DISTINCTIVE FEATURES

Cervical Small bodies, large vertebral foramina, foramina in tra

processes, anterior and posterior tubercles, bifid spino

transverse foramina

Thoracic Heart-shaped bodies, long spinous processes angled p

costal facets for rib articulation on bodies and transve

Lumbar Large kidney-bean-shaped bodies, sturdy laminae, thic

spinous processes, mammillary processes on the postthe superior articular facets (processes)

Sacral Fused as sacrum, four pairs of dorsal and ventral foram

exit and triangular sacral canal

Coccygeal Fused as small triangular bonethe coccyx


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Vasculature of Vertebral Colum Segmental branches of vert

ascending cervical arteries

The major segmental arteritrunk:

Posterior intercostal artethoracic region

Subcostal and lumbar artthe abdomen

Iliolumbar and lateral ansacral arteries in the pelv


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Spinal cord and back

Obj ti


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Draw and label the parts of a sp

Understand the different types o

nerve carries.

Describe the Meninges and the c

significance of where to perform

Draw a schematic transverse sec

the spinal cord, meninges, and v

Understand the structure and fudorsal and ventral spinal nerve r

Know the levels of the principle

Describe the vasculature supply

cord and vertebral column

Objective

Spinal co


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Spinal co

Originates at the inferiomedulla oblongata and

as conus medullaris

Is approximately 42 to 4from the foramen magn

Is connected from the c

medullaris to the coccyxfilum terminale(a stranconnective tissue that cexits from the dural sacthrough the sacral hiatu

S i l


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Spinal co Cervical enlargement - corre

roughly to the brachial plexu

which innervate the upper lispinal cord segments from a

The vertebral levels of the e

roughly the same (C4 to T1).

Lumbosacral enlargement - c

the lumbosacral plexu nerve

innervate the lower limb. It

spinal cord segments from L

found about the vertebral le

T12.


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l


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Spinal co

Has the following featur

section Dorsal median sulcus an

median fissure that dividsymmetrical halves

Central canal carrying ce

fluid (CSF) White matter surroundi

shaped core of grey matand dorsal horns)


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Spinal co

Structure of Spinal Ner

of spinal nerves 8 cervical, 12 thoracic, 5

sacral, 1 coccygeal

C1C7 exit superior to co

vertebrae

C8 exits inferior to the C

T1Co exit inferior to co

vertebrae

l


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Spinal cor

Ventral roots

Carry efferent (motor) fibtheir cell bodies in the vethe cord

May contain presynaptic afibers

Dorsal roots

Carry afferent (general ansensory) fibers with their in the dorsal root ganglio

May be absent in C1 and

Spinal co


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Spinal co

Ventral and dorsal rootto form a (mixed) spinalexits through the interveforamen and divides almimmediately into (mixedand dorsal rami

Caudal equina:spinal ninferior to the conus metravelling obliquely to excanal


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Segmental

Level

Number of

Nerves Level of Exit from Vertebral Column


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Level Nerves Level of Exit from Vertebral Column

Cervical 8 (C1-C8) Nerve C1a(suboccipital nerve) passes superior to

Nerves C2-C7 pass through IV foramina superior t

corresponding vertebrae

Nerve C8 passes through the IV foramen between

T1

Thoracic 12 (T1-T12) Nerves T1-L5 pass through IV foramina inferior to

vertebrae

Lumbar 5 (L1-L5)

Sacral 5 (S1-S5) Nerves S1-S4 branch into anterior and posterior r

sacrum, with the respective rami passing through

posterior sacral foramina

Coccygeala 1 (Co1) The 5th sacral and coccygeal nerves pass through

a

The first cervical nerves lack posterior roots in 50% of people, and the coccygeal

S i l


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Spinal segmen Because the vertebral column g

than the spinal cord, spinal cor

not correspond to vertebral segadults, especially in the lower s

In the fetus, vertebral segment

correspond with spinal cord seg

adult, however, the spinal cordthe L1/L2 vertebral level, formi

known as the conus medullaris

lumbar and sacral spinal cord s

found between vertebral levels

Meninges


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g

Dura mater:

Tough fibroelastic membrane

Attached to the margins of the foramposterior longitudinal ligament

Separated by the epidural space from

periosteum

Extends as a sac from the margin of t

magnum to the level of S2

Pierced by spinal nerves

Anchored to the coccyx by the ex

terminale

Forms dural root sleeves covering

nerves before fusing with the epi

Meninges


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g

Arachnoid mater:

Delicate, avascular, fibroelastic

lining dural sac Opposed to dura by CSF pressu

Is external to the subarachnoidbetween arachnoid and pia, cotraversed by strands of connec

(arachnoid trabeculae)

Contains the lumbar cistern, anenlargement of subarachnoid sbetween L2 and S2

Meninge


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Meninge

Pia mater:

Highly vascular innermocovering roots of spinal

Continues as the filum t

Suspends the spinal cor

the dural sac by lateralextensions between theand posterior roots, caldenticulate ligaments


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Dermatom


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Dermatom

A well-defined strip of skin exten

anterior to the posterior midline

single spinal nerve

Cervical supply neck and upper li

Thoracic supply trunk (T1 also su

limb)

C5 abuts T1 on the superior ante Lumbar predominantly supply an

limb

Sacral predominantly supply post

limb

LEVEL SOMATIC SUPPLYC5 Cl i l


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C5 Clavicles

T4 Nipples

T10 Level of umbilicuL1 Inguinal ligament

L3/4 Over the knee

S2S4 Perineum


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SPINAL CORD

BLOOD SUPPLY TO THE SPINAL CORD

Anterior spinal a


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Is a single artery runnin

ventromedian fissure

Arising from branches o

vertebral arteries (with

contributions from the a

cervical, deep cervical, i

lumbar, and sacral arter

Supplies the anterior tw

the spinal cord and vert

bodies

p

Posterior spina


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Are paired, longitu

arteries arising frovertebral or poster

cerebellar arteries

Supply posterior o

the spinal cord and

bodies

SEGMENTAL ART


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Anterior and posterior segme

medullary arteries are derive

spinal branches of the ascend

deep cervical, posterior inter

lumbar arteries.

The medullary segmental art

located chiefly where the neeblood supply to the spinal co

greatestthe cervical and lu

enlargements

SEGMENTAL ARTERIE


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These arteries enter the

canal through the interveforamina and reinforce thanterior and paired postespinal arteries.

It is the segmental medu

arteries that primarily pradditional vascularizationspinal cord

SEGMENTAL ARTER


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Great anterior segmental art

Adamkiewicz)

Occurs on the left side in 65%individuals

Contributes to two thirds of t

to the inferior spinal cord

It typically arises from a left p

intercostal artery, which branthe aorta, and supplies the lo

thirds of the spinal cord via th

spinal artery

RADICULAR ART


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The dorsal and ventral raarteries are also derived spinal branches of the ascervical, deep cervical, pintercostal, and lumbar a

These arteries course alonerve roots (all except th

supplied by a segmental artery) and supply blooddorsal and ventral roots ospinal nerves and their co

RADICULAR ART


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The dorsal and ventral

arteries typically do nothe anterior or posteri

arteries.

Most radicular arterieand supply only the ne


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VEINS OF SPINAL C


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Veins:Usually 3 anterior and 3

longitudinal spinal veins with tr

the posterior medullary and rad

They drain into the valveless veplexus.

Vertebral venous plexus is cont

cranial dural venous sinuses an

valves

Internal vertebral plexus (lyextradural space) drains the

External vertebral plexus co

azygos vein, superior and in

cavae


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Clinical releva


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Compression of spinal

Lumbar spinal punctur

Spinal anesthesia

Epidural anesthesia

Ischemia of spinal cord

Spinal cord injuries

Clinical poin


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Epidural hematom

Subdural hemato

Meningitis


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Muscles of back

Superficial back,


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Muscles of the b


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The extrinsic back muscle

superficial and intermedi

that produce and controlrespiratory movements, r

The intrinsic (deep) back

include muscles that spec

on the vertebral column, its movements and maint

posture


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SUPERFICIAL EXTRINSIC MUSCLES OF B

MUSCLE ORIGIN INSERTION ACTION

Trapezius Ligamentum Lateral clavicle, Elevates,


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nuchae; spines

of C7T12

acromion,

spine of

scapula,

retracts, and

rotates

scapulaLatissimus

dorsi

Spines of T6

T12,

thoracolumbar

fascia, iliac

crest

Intertubercular

groove of

humerus

Extends,

adducts,

medially

rotates

humerus

Levator

scapulae

Transverse

processes C1

C4

Superior

medial border

of scapula

Elevates

scapula

MUSCLE ORIGIN INSERTION

ACTION IN

Rh b i S i I f i R t t d D


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Rhomboi

d minor

Spines

of C7

T1

Inferior

medial

borderof

scapula

Retracts and

rotates

scapula

Do

sc

Rhomboi

d major

Spines

of T2

T5

Inferior

medial

border

of

Retracts and

rotates

scapula

Do

sc


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INTERMEDIATE EXTRINSIC MUSCLES OF

MUSCLE ORIGIN INSERTION ACTION

I


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Serratus

posteriorsuperior

Spines of

C7T3

Superior

border ofribs 25

Elevate

s ribs

In

nT

Serratus

posterior

inferior

Spines of

T11L2

Inferior

border of

ribs 812

Depres

ses

ribs

In

n

T


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Triangle of auscul


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It has the following bou

Superiorly and medially,inferior portion of the Tr

Inferiorly, by the Latissim

Laterally, by the medial

the scapula


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BACK

DEEP BACK

MUSCLE ORIGIN INSERTION

Superficial layer: splenius

Splenius capitis

Splenius cervicis

Ligamentum nuchae

Spinous processes of

Capitis: Mastoid,

nuchal line

Un

fle


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Splenius cervicis Spinous processes of

C7T3/4

nuchal line

Cervicis: Transverse

processes C1C4

fle

To

he

Intermediate layer: erector spinae

Iliocostalis Sacrum, iliac crests,

and lumbar spinous

processes

Angles of ribs Un

fle

To

ve

he

Longissimus Thoracic and C

ervical transverse

processes, and tomastoid process

Spinalis Thoracic spinous

processes, skull


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Deep layer: transversospinalis

Semispinalis Transverse

processes C4

Occipital bone,

spinous processes

Ex

rot


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T12 46 segments

above

co

Multifidus Sacrum, ilium,

transverse

processes T1T3

Spinous processes

24 segments

above

Sta

ve

du

mo

Rotatores Transverse

processes

Spinous processes

12 segments

above

Lo

an

ve

co

Minor deep layer

Interspinales C and L spinous

processes

Spinous process above


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Intertransvers

arii

C and L transverse

processes

Transverse processes

above

LevatorescostarumTips of transverseprocesses C7T11

Ribs, between tubercleand angle


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Intermediate layer


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Interspinales , intertransversii,Levtores costorum


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Flexion Extension Lateral Bending Rotation (n

Bilateral action of

Longus coli

Scalene

Deep neck muscles

1,semispinalis

cervicis and

Unilateral action of

Iliocostalis cervicis

Longissimus capitis

Unilateral a

Rotatores S

capitis and


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Scalene

Sternocleidomast

oid

cervicis and

iliocostalis cervicis

2,splenius cervicisand levator

scapulae

3,splenius capitis

4,multifidus

5,longissimuscapitis

6,semispinalis

capitis

T,trapezius

Longissimus capitis

and cervicis Splenius

capitis and cervicisIntertransversarii

and scalenes

capitis and

Multifidus

Suboccipital MusclesMuscle Origin Insertion

Rectus capitis

posterior major

Spinous process of

vertebra C2

Lateral part of infer

of occipital bone


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posterior major vertebra C2 of occipital bone

Rectus capitisposterior minor

Posterior tubercle ofposterior arch of

vertebra C1

Medial part of inferof occipital bone

Obliquus capitis

inferior

Posterior tubercle of

posterior arch of

vertebra C2

Transverse process

Obliquus capitis

superior

Transverse process of

vertebra C1

Occipital bone betw

and inferior nuchal

Suboccipital Triangle

Aspect of Triangle Structures

Superomedial boundary Rectus capitis posterior maj


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Superolateral boundary Obliquus capitis superior

Inferolateral boundary Obliquus capitis inferior

Floor Posterior atlanto-occipital m

posterior arch of vertebra C

Roof Semispinalis capitis

Contents Vertebral artery and subocc


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back and spinal cord

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