Spinal cord

4. spinal cordspinal cord

5. Spinal cordSpinal cord
Origin:Origin:

foramen megnum continous withforamen megnum continous with
medulla oblongata of brainmedulla oblongata of brain
TerminationTermination
 in adultin adult

at the lower boarder of L1at the lower boarder of L1
 in childin child
at the upper boarder of L3at the upper boarder of L3

8. MeningsMenings
The spinal cord is surrounded by three membranesThe spinal cord is surrounded by three membranes
11dura materdura mater
2 :arachnoid mater2 :arachnoid mater
3:pia mater3:pia mater::
Function’Function’
ProtectionProtection
Also by cerebrospinal fluid present in the subarachnoid spaceAlso by cerebrospinal fluid present in the subarachnoid space

10.  In the cervical regionIn the cervical region
 it gives origin to the brachial plexusit gives origin to the brachial plexus
 lower thoracic region and lumberlower thoracic region and lumber
regionregion
 it gives origin to lumbosacral plexus .it gives origin to lumbosacral plexus .
 superiorlysuperiorly
 the spinal cord is fusiformly enlarge the enlargementthe spinal cord is fusiformly enlarge the enlargement
is referred as the cervical and lumber enlargementis referred as the cervical and lumber enlargement
 inferiorlyinferiorly
 the spinal cord tapers off into the conus medullaristhe spinal cord tapers off into the conus medullaris
from the apex of which a prolongation of pia materfrom the apex of which a prolongation of pia mater
the filum terminale descend to be attached to thethe filum terminale descend to be attached to the
posterior surface of the coccyx.posterior surface of the coccyx.

11. locationlocation
 The cord lie in midlineThe cord lie in midline
 anterior median fissureanterior median fissure
 posterior median sulcus.posterior median sulcus.
 Along the entire length of the spinal cord areAlong the entire length of the spinal cord are
attached 31 no of spinal nerves by theattached 31 no of spinal nerves by the
 anterior or motor roots andanterior or motor roots and
 Posterior root or sensoryPosterior root or sensory
 posterior root ganglionposterior root ganglion
 cells which gives rise to peripheral and centercells which gives rise to peripheral and center
nerve fibbernerve fibber

13. Structure of spinal cordStructure of spinal cord
 gray matergray mater
 innerinner
 white materwhite mater

OuterOuter
 GRAY MATERGRAY MATER

On croos section the gray mater is seenOn croos section the gray mater is seen H-shapedH-shaped pillar withpillar with
 anterioranterior column or hornscolumn or horns

posterior column or hornsposterior column or horns
 lateral gray column or horn (THORACIC ANDlateral gray column or horn (THORACIC AND
LUMBER)LUMBER)
 united byunited by
 gray commissuregray commissure
 With central canalWith central canal

15. Nerves cell groups in the anteriorNerves cell groups in the anterior
gray columngray column
 Alpha efferentAlpha efferent
nervenerve
 largelarge
 MultipolarMultipolar
 It innervates the skeletalIt innervates the skeletal
musclemuscle
 Axon pass out inAxon pass out in
anterior roots of spinalanterior roots of spinal
nervesnerves
 Gamma efferentGamma efferent
 SmallSmall
 MultipolarMultipolar
 It innervates intrafusalIt innervates intrafusal
muscle fibers ofmuscle fibers of
neuromuscular spindlesneuromuscular spindles
 Axon may pass out inAxon may pass out in
anterior roots of theanterior roots of the
spinal nervesspinal nerves

16. Nerve cell of the anterior gray columnNerve cell of the anterior gray column
is divided into three basic groupsis divided into three basic groups

(1) MEDIAL GROUP(1) MEDIAL GROUP
 (2) CENTRAL GROUP(2) CENTRAL GROUP
 (3) LATERAL GROUP(3) LATERAL GROUP

17. Medial groupMedial group
EXTENTIONEXTENTION
 WHOLE SPINAL CORDWHOLE SPINAL CORD
 innervateinnervate
 muscle ofmuscle of
 neck,neck,
 trunk,trunk,
 intercostalintercostal
 abdominalabdominal

18. (2)Central group:(2)Central group:
EXTENTIONEXTENTION
cervical, lumber, sacral segmentscervical, lumber, sacral segments
Three nucleiThree nuclei
(a)(a) phrenic nucleusphrenic nucleus
(C(C3’4’5)3’4’5)
INERVATEINERVATE
DIAGHPHRAMDIAGHPHRAM
(b)(b)accessory nucleusaccessory nucleus))
(C(C5 OR 6)5 OR 6)
INNERVATIONINNERVATION
sternocliedomastoid and trapezius musclesternocliedomastoid and trapezius muscle
(c) lumbosacral nucleus(c) lumbosacral nucleus
(L2 TO S1)(L2 TO S1)
INNERVATIONINNERVATION
unknwon distributionunknwon distribution

19. Lateral groupLateral group
 ExtentionExtention
 cervical and lumbosacral segmentcervical and lumbosacral segment
 InnervationInnervation
 MusclesMuscles
 (1) upper limb(1) upper limb
 (2) lower limb(2) lower limb

20. Nerve cells of the posterior grayNerve cells of the posterior gray
columncolumn
 four nerve cell groupfour nerve cell group
 1 substantia gelatinosa1 substantia gelatinosa
 2 nucleus propius2 nucleus propius
 3 nucleus dorsalis (clarks column)3 nucleus dorsalis (clarks column)
 4 visceral afferent nucleus4 visceral afferent nucleus
 First twoFirst two
 extentionextention
 through out the length of the cordthrough out the length of the cord
 other twoother two
 extentionextention
 lumber and thoracic segmentslumber and thoracic segments

21. Substantia gelatinosaSubstantia gelatinosa
 locationlocation
 apex of the posterior gray columnapex of the posterior gray column
 composedcomposed
 Golgi type 2 neuronGolgi type 2 neuron
 functionfunction
 receives afferent fiber associated withreceives afferent fiber associated with
 pain ,pain ,
 temperaturetemperature
 touch.touch.
 Furthermore it receive input from the descendingFurthermore it receive input from the descending
fibers from the supraspinal level .fibers from the supraspinal level .

22. Nucleus propiusNucleus propius
 LocationLocation
 Below s gBelow s g
 FunctionFunction
 senses ofsenses of
 positionposition
 movement (proprioception)movement (proprioception)
 two points discriminationtwo points discrimination
 vibrationvibration

23. Nucleus dorsalisNucleus dorsalis
 LocationLocation
 base of the posterior gray columnbase of the posterior gray column
 extendingextending
 CC8 to8 to LL3 43 4
 FUNCTIONFUNCTION
 proprioceptive endingsproprioceptive endings
neuromuscular spindles and tendonneuromuscular spindles and tendon
spindlespindle

24. Visceral afferent nucleusVisceral afferent nucleus
 LOCATIONLOCATION
 lateral to the nucleus dorsalislateral to the nucleus dorsalis
 EXTENTIONEXTENTION
 TT11 toto LL22
 FUNCTIONFUNCTION
 receiving visceral afferent informationreceiving visceral afferent information

25. Nerve cell group lateral gray columnNerve cell group lateral gray column
 ExtendExtend
 TT11 TO STO S44
 CellsCells
 T1 TO L3T1 TO L3
 preganglionic sympathetic nerve fiberpreganglionic sympathetic nerve fiber
 CELLSCELLS

S 2,3,4S 2,3,4
 preganglionic parasympatheticpreganglionic parasympathetic
fiberfiber

26. The gray commissure and centralThe gray commissure and central
canalcanal

LOCATIONLOCATION
 the anterior and posterior gray columns on each side are connectedthe anterior and posterior gray columns on each side are connected
by a transverse gray commissure so that the gray column r in theby a transverse gray commissure so that the gray column r in the
central of the gray commissure is situated central canal.central of the gray commissure is situated central canal.
 SuperiorlySuperiorly
 above this it open into the cavity of the fourth ventricleabove this it open into the cavity of the fourth ventricle
 continuous with the central canal of the caudal half of the medullacontinuous with the central canal of the caudal half of the medulla
oblongataoblongata
 InferiorlyInferiorly
 It is closedIt is closed
 conus medullaris it expend into the fusiform terminal ventricleconus medullaris it expend into the fusiform terminal ventricle
 terminate below with in the root of the filum terminaleterminate below with in the root of the filum terminale
 It is filled with cerebrospinal fluid and is lined with epithelium calledIt is filled with cerebrospinal fluid and is lined with epithelium called
the ependymathe ependyma

27.  IT resembles letter HIT resembles letter H
 posterior gray commissureposterior gray commissure
 The part of the gray commissure that isThe part of the gray commissure that is
situated posterior gray canalsituated posterior gray canal
 Anterior gray commisureAnterior gray commisure
 lie anterior to the canallie anterior to the canal


28. White materWhite mater
 It is divided intoIt is divided into
 anterior lateralanterior lateral
 posterior white columns or finiculi.posterior white columns or finiculi.
 anterior columnanterior column
 locationlocation
 lie on each side lie in between the midline and the point of emergencelie on each side lie in between the midline and the point of emergence
of the anterior nerve root .of the anterior nerve root .
 lateral columnlateral column
 locationlocation
 between the emergence of the anterior nerve root and the entry of thebetween the emergence of the anterior nerve root and the entry of the
posterior nerve root theposterior nerve root the
 posterior columnposterior column
 locationlocation
 in between the entry of posterior nerve root and midlinein between the entry of posterior nerve root and midline

30. StructureStructure
 compositioncomposition
 in centrral nervous system the white mater of spinalin centrral nervous system the white mater of spinal
cord consist of a mixture ofcord consist of a mixture of
 nerve fibernerve fiber
 neuroglianeuroglia
 blood vesselblood vessel
 it surrounds the gray materit surrounds the gray mater
 its white color is due to the high proportion ofits white color is due to the high proportion of
myelinated nerve fibermyelinated nerve fiber

31.  Blood Supply of the Spinal CordBlood Supply of the Spinal Cord
 The spinal cord receives its arterial supply from threeThe spinal cord receives its arterial supply from three
small, longitudinally running arteries:small, longitudinally running arteries: the twothe two
posterior spinal arteriesposterior spinal arteries andand one anterior spinalone anterior spinal
artery.artery. The posterior spinal arteries, which ariseThe posterior spinal arteries, which arise
either directly or indirectly from the vertebral arteries,either directly or indirectly from the vertebral arteries,
run down the side of the spinal cord, close to therun down the side of the spinal cord, close to the
attachments of the posterior spinal nerve roots. Theattachments of the posterior spinal nerve roots. The
anterior spinal arteries, which arise from the vertebralanterior spinal arteries, which arise from the vertebral
arteries, unite to form a single artery, which runsarteries, unite to form a single artery, which runs
down within the anterior median fissure.down within the anterior median fissure.
 The posterior and anterior spinal arteries areThe posterior and anterior spinal arteries are
reinforced by radicular arteriesreinforced by radicular arteries, which enter the, which enter the
vertebral canal through the intervertebral foramina.vertebral canal through the intervertebral foramina.
 The veinsThe veins of the spinal cord drain into the internalof the spinal cord drain into the internal
vertebral venous plexus.vertebral venous plexus.