Download MBBS Important Topics Spinal Cord Internal Features

Dovsal Hbrm

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Cembsl amj? o Anteoror
.
Posterior median sulcus . Fo S ?l?t?'\ oY
Central canal

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Figure 3.2: Three-dimensional view of grey matter of the spinal
SG?V"'*T Co\uMn-
* ?<'?L""? P"'Tu.k'n' 'j ~ M?u?r W seem 1m
?+hovalie & Saeral qu\:s - o(o\Jrumj ?mj co\.uwn.
Posterior median septum

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Posterior funiculus
g
Dorsal grey
column Posterolateral

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sulcus
Lateral
funiculus
S Grey
commissure ? Po s ?I?Q?Y\?o ~

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Ventalwhite '_ a bearod T"urm'cd w = W "\;?Lf_ ma j(: leer
Lateral
grey column
Ventral grey
column

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Anterior funiculus:
?_
commissure
? . oY
i Am koo White eofumin

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Figure 3.1: Transverse section through the spinal cord showing grey
and white matter
B Cervical B Thoracic

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. S?narcj T?amvt'r-?e seckn 1 Ovad ~? Cevrviend (?y?v?
Round ? Thovatde & Sacwal. @ @
KOU?I'WI/OVM T Lumk?d Lumbar B sacral
. G'fa MA" L"' \:? Qkq L ;"\ cl"?d L th Lc? . Figures 3.3A to D: Differences in appearance of transverse
sections through various levels of the spinal cord

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? WWie matkr decmones dowm the Wne.
Nuclear cell columns Lamina of Rexed

Posteromarginal nucleus

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Substantia gelatinosa

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Nudeus proprivs G
L 1 Nudeus dorsalis Laminall
',QWUVIQ I ?"_ly_ 1 DOTSG., PQ"?": (DOY5?J L\b'f?) t::::l\:;
. ? Int fiolateral nucleus Lamina V
s lomind T 2 T 1 Base g (borsal horm) Seitindinin

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Lamina VIl
Lateral group
'('?w""? \/T_r : :I"?\ '\.9.'7 MQAA:A\,'E a.?"?a wLlW\'IL . Central group LL::::I:
Loawina NIT 2 TX ? Venlead horn
.xaw?r\? Z t Canbrod Y-

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Medial group
Figure 3.4: Nuclei and laminae of Rexed
Posteromarginal nucleus

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Lumbosacral Substantia gelatinosa
nucleus

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Nucleus proprius
Accessory
nucleus
Phrenic
Nucleus dorsalis

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(Clarke?s column)



Central group

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=
nucleus Retrodorsolateral ] 2 Intermedio-
a . o lateral nucleus

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3 [ Dorsomedial Dorsolateral (o .
S| nucleus 3 Intarmedio-
= s Ventrolateral J & medial nucleus
S| Ventromedial ?
8| nucleus

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=

Figures 3.7A and B: (A) Nerve cell groups in the anterior grey column; (B) | Figure 3.5: Nerve cell groups in the posterior grey column

TABLE 3.2: Nerve cell groups and their connections (Posterior

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TABLE 3.3: Nerve cell groups and their connections (Lateral grey column)

grey column)

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o Zm e Nuclei in grey column Afferent connections Efferent connections
Rexed Nucleiin Afferent Efferent

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lamina grey column connections connections Central cervical nucleus :;T?;;:';oceptlon from neck, semicircular . aateral cerebellum and vestibular nucleus
?Fast? pin?pricking tGI\;etS orllgln :;)Isl:fr::))r thoracic (Clarke?s Proprioception from lower limbs sGanrlr!?a: ;)izgln to posterior spinocerebellar tract of
0O lateral
Posteromar- type of pain from vi o
| 5 spinothalamic 0 . < . Intermediolateral nucleus, hypothalamus,

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gma| nucleus dorsolateral tract of trpact of the Intermediomedial nucleus Interoception from viscera s
Lissauer G i i joni i
opposite side e e _Hypothal_amus, retlcularformatlon, Preganglionic autonomics to smooth muscles
intermediomedial nucleus and glands
Stimulation from Presynaptic

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= large diameter inhibition
I Z:It;stti:z:: Sy S e TABLE 3.4: Nerve cell groups and their connections (Anterior grey column)
;ink:?bltory from pain E.mp" u3$6()5ee zmlna Nucleiin grey column Afferent connections Efferent connections
res gure 3.
" = o ey . o i o Gives origin to anterior

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Fibres carrying Gives origin to Spinal border nucleus Proprioception from lower limbs spinocerebellar tract of opposite side
i vil
Il and Nucleus sensation of crude an_terolaterall Interneurons for motor Corticospinal and extrapyramidal tracts, other spinal
M
Y PR touch, pressure, spinothalamic e o atorneurons

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RSB thermal and?slow? tracts of the Ve f e ATy :
s 3 o lentromedial nucleus Corticospinal, spinal interneurons, muscle spindle Dorsal muscles of trunk
burning pain opposite side
Dorsomedial nucleus Corticospinal, spinal interneurons and muscle spindle Ventral muscles of trunk
Exteroceptive, Spinal accessory Corticospinal, spinal interneurons, muscle spindle Sternocleidomastoid and trapezius

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i nociceptive, Gives origin to ey R
Diffuse 3 4 d v icul Efemrs Corticospinal, spinal interneurons, medullary Diaphragm
il proprioceptive and spinoreticular, respiratory centre g
Vv e visceral senses; spinotectal and X Ay
reticular i i i i Nucleus of Onuf Spinal interneurons and visceral afferents fielucciaptiagLiinialy)

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nucleus cortlcospmall tract spino-olivary B sphincters of urethra and anal canal
and subcortical tracts FOR e = z
inputs Ventrolateral Corticospinal, spinal interneurons and muscle spindle Dorsal muscles of limbs
Dorsolateral Corticospinal, spinal interneurons and muscle spindle Ventral muscles of limbs
Exte:roceptlve, Retrodorsolateral Corticospinal, spinal interneurons and muscle spindle ~ Muscles of hand and foot

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Interneurons nociceptive, Motor neurons
VI for spinal proprioceptive for superficial
reflexes senses; spinal reflexes
L corticospinal tract

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mevrve
i\ conec'l'('tm ;FILMJ wi blom t+he CNS ,'\"\q?: whV\uL& oo MO S SJ?YQI
o bler ) Wi cm?u! a teock (OIT aSu?cdu)
boh Ascendi %
' ASCW\ CL?] y Pascten &m\j ov Tv\\-:-vSe?] Mmlzd- b?j?-\?"?j .

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. T-rdci?s ave Pr?ovnl: im Wik Mall-g-v.
TABLE 3.5: Important ascending and descending tracts in various funiculi
Ascending tracts Descending tracts
Septomarginal tract
Fasciculus interfascicularis (Semilunar tract/ Comma tract of

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Schultze)

Spinal cord Medulla Pons Midbrain
Corticospinal tract
Funiculus

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@
O
Tectospinal tract O
Rubrospinal tract ?

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Posterior
Fasciculus gracilis
Fasciculus cuneatus

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Lateral ? Posterior spinocerebellar ? Lateral corticospinal
? Anterior spinocerebellar ? Rubrospinal Vestibulospinal tract 3 2
? Lateral spinothalamic ? Lateral reticulospinal 2
? Spinotectal ? Olivospinal

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? Spino-olivary ? Hypothalamospinal 2
? Dorsolateral (Lissauer?s tract) ? Raphespinal '?"Qg
Anterior . Anferior}pincthalamic . Anteriorcor(icospin# Reticulospinal tracts 3
? Spinoreticular ? (Lateral) vestibulospinal
? Medial vestibulospinal (Medial longitudinal fasciculus)

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? Tectospinal
+ Medial reticulospinal Spinalcord Medulla Pons Midbrain

ASCENDING TRACTS(Blue) DESCENDING TRACTS(Red)
Lateral spinothalamic tract (spinal lemniscus)

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Septomarginal tract
Tvaek 0 C?m'
T'FA;[? j Burdoch Casclolin e

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Comma tract
Anterior spinothatamic tract
~_

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Raphespinal ract Fasciculus gracilis
e
Lateral
spinothalamic tract
Posterior Hypothalamospinal tract ?_?

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spinocerebellar tract Fasciculus
) C Lot criospnal vt cuneatus
Spinotectal tract O
Spino-olivary tract ~ R
?(e

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Rubrospinal tract
. ? \1 Lateal reticulospinal ract
ne ue Anterior B
Spinocerebelar act
Spinotectal tract Medial reticulospinal tract

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e Vibra -\?\'m
?Spino-olivary tract
o Joimk fosikisn,

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Olivospinal tract
Vestibulospinal tract
Tectospinal tract

spinothalamic tract

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. MM Ctg rngm'ou.
hion -
Figure 3.9: Positions of the main ascending and descending tracts present in a transverse section of the spinal cord
Anterior
corticospinal tract

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1) Jejjeqaied
-ouids [esioq

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wnyjgased

Yoes) sefjaqeseoouids
[eAuaA

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TABLE 3.6: Ascending tracts of spinal cord

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Tract Function First-order neuron Second-order neuron Third-order neuron
Peripheral Cell Central Cellbody Crossing Ascent Cellbody Axons
process body process
Fasciculus Fine touch, Skin, joint, Dorsal Fasciculus Nucleus Internal Medial Ventral Superior
gracilis proprioception, tendon nerve gracilisin gracilisin arcuate lemniscus postero- thalamic

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vibration, joint root the posterior medulla fibres lateral radiation to
position sense ganglia funiculus oblongata nucleus of postcentral
from below T6 thalamus gyrus
Fasciculus Fine touch, Skin, joint, Dorsal Fasciculus Nucleus Internal Medial Ventral Superior
cuneatus proprioception, tendon nerve cuneatusin cuneatus arcuate lemniscus postero- thalamic

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vibration, joint root the posterior in medulla fibres lateral radiation to
position sense ganglia funiculus oblongata nucleus of postcentral
from above T6 thalamus gyrus
Anterior Crude touch, Skin Dorsal Synapses Nucleus Anterior Joins Ventral Superior
spino- pressure nerve with nucleus proprius white com- medial postero- thalamic

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thalamic root propriusof in spinal missure of lemnis- lateral radiation to
tract ganglia spinalcord cord spinal cord cusin nucleus of postcentral
medulla thalamus gyrus
oblongata
Lateral Pain and ther- Skin Dorsal Ascends few Nucleus Anterior Continues Ventral Superior

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spino- mal sensation nerve segments postero- white com- asspinal postero- thalamic
thalamic root upindorso- mar- missure of lemniscus lateral radiation to
tract ganglia lateraltract ginaland spinalcord in brain- nucleus of postcentral
of Lissauer nucleus stem thalamus gyrus
proprius

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Posterior Unconscious Muscles Dorsal Ascendsin Posterior Termi-
spinocer- proprioception and joints nerve fasciculus thoracic nates in
ebellar from lower of lower root till Clarke?s nucleus anterior
limb limb ganglia column - lobe of - B
cerebel-

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lum
Anterior Unconscious Muscles Dorsal Synapses Spinal Anterior Termi-
spinocer- proprioception andjoints nerve withspinal border white com- nates in
ebellar from lower of lower root border cells cells missure of anterior
limb limb ganglia spinal cord lobe of - -

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cerebel-
lum
Spino- Deep pain Deeptis- Dorsal Synapses LaminaV Anterior Reticular
reticular sues nerve withcellsin ofRRexed whitecom- formation
tract root lamina V missure of of brain-

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ganglia spinal cord; stem ? ?
some fibres
do not
cross
Spino- Feedback Muscles Dorsal Synapses LaminaV Anterior Inferior

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olivary about perfor- andjoints nerve withcellsin of Rexed white com- olivary
tract mance root lamina V missureof nucleus of ? ?_
ganglia spinal cord medulla
oblongata
Spinotec- Reflex move- Skin, joint, Dorsal Synapses LaminaV Anterior Superior

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tal tract ments of the muscles nerve withcellsin of Rexed white com- colliculus
head and eyes root laminaV missure of of mid- = i
spinal cord _brai

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Tract Crossing Termination Funiculus Function
of cord
Lateral corticospinal Cerebral cortexarea4, Lower medulla Interneuron and Lateral Fine motor function of
area6, and areas 3, 1,2 alpha motor neuron distal muscles of limb and
modulation of senses

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Anterior Cerebral cortexarea4, Just before Interneuron and Anterior Gross motor function of
corticospinal area6,andareas 3,1,2 termination in the alpha motor neuron axial musculature
spinal cord
Rubrospinal Red nucleus Upper midbrain Gamma motor Lateral Facilitates flexors of upper
neuron limb

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Tectospinal tract Superior colliculus Upper midbrain Interneurons Anterior Reflex postural
movements of neck
Medial Pontine reticular ? Gamma motor Anterior Facilitates extensors and
reticulospinal tract formation neuron bladder, bowel control
Lateral Medullary reticular Various levels ?Gamma motor Lateral Facilitates flexors,

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reticulospinal tract formation neuron automatic breathing,
modulation of pain
Lateral Lateral vestibular ? Alpha motor neuron Anterior Facilitates extensors
vestibulospinal nucleus
tract

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Medial Medial vestibular Upper midbrain Alpha motor neuron Anterior Turning of head
vestibulospinal nucleus
tract (MLF)
Olivospinal Inferior olivary nucleus Upper medulla Interneurons Lateral Feedback to spino-olivary
tract

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Descending Limbic lobe, ? Preganglionic Lateral Control autonomic output
autonomic hypothalamus autonomic neurons
Raphespinal Raphe magnus nucleus ? Dorsal horn Lateral Pain inhibition by release

of serotonin

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*
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