Beginning: Beginning: At the foramen magnum as a At the foramen magnum as a

continuation of continuation of thethe Medulla Oblongata of the Medulla Oblongata of the

brain. brain. Shape:Shape: Cylindrical.Cylindrical. Length: Length: About (45) cm.About (45) cm. Occupies:Occupies: Upper 2/3 of the vertebral Upper 2/3 of the vertebral

(spinal) canal of the vertebral (spinal) canal of the vertebral column.column.

(1) Up till the 3(1) Up till the 3rdrd month of month of Fetal Life: Fetal Life:

The spinal cord occupies the The spinal cord occupies the Entire Length of the Entire Length of the vertebral canal.vertebral canal.

(2) At birth : (2) At birth : It terminates at the level of It terminates at the level of

L3.L3.

(3) Children :(3) Children : It ends at the Upper It ends at the Upper

Border of the Border of the 33rdrd Lumbar vertebra.Lumbar vertebra.

(4) Adults :(4) Adults : It terminates at the It terminates at the

Intervertebral disc (Intervertebral disc (11st-st-

2nd )2nd ) Lumbar vertebrae.Lumbar vertebrae.

Cervical:Cervical:(C3- T1) Segments.(C3- T1) Segments. For theFor the Brachial Brachial

Plexus.Plexus.Lumbar:Lumbar: (L1- S3) Segments(L1- S3) Segments.. For theFor the LumbarLumbar and and Sacral Sacral

Plexuses.Plexuses.

Conus Medullaris:Conus Medullaris: A conical termination A conical termination

Caudal to the Lumbar Caudal to the Lumbar Enlargement.Enlargement.

FilumTerminale:FilumTerminale: A filament of connective A filament of connective

tissue arises from the tip tissue arises from the tip of the conus. of the conus.

It is attached to the It is attached to the 11stst CoccygealCoccygeal Vertebra.Vertebra.

Anterior:Anterior: Deep AnteriorDeep Anterior

(Ventral)(Ventral) MedianMedian Fissure.Fissure.

Posterior:Posterior: Shallow Posterior Shallow Posterior Median Sulcus. Median Sulcus.

The Spinal Cord The Spinal Cord receivesreceives

Information from Information from and Controls the and Controls the Movement of the Movement of the Trunk and Limbs.Trunk and Limbs.

It has (It has (3131) paired ) paired Spinal Nerves.Spinal Nerves.

Two linear series (6-8)Two linear series (6-8) of of Nerve FasciclesNerve Fascicles areare attached to theattached to the DorsolateralDorsolateral and and Ventrolateral aspects of Ventrolateral aspects of the cord.the cord.

The Fascicles coalesce toThe Fascicles coalesce to formform Dorsal Dorsal andand VentralVentral Nerve Roots.Nerve Roots.

The Roots pass to The Roots pass to their their correspondingcorresponding Inter vertebral Inter vertebral Foramena.Foramena.

Near which they Near which they join to form thejoin to form the Spinal Nerve Spinal Nerve Proper.Proper.

Carry: Carry: Primary AfferentPrimary Afferent

NeuronsNeurons from the from the peripheral sensory peripheral sensory receptors to the receptors to the spinal cord and brain spinal cord and brain stem. stem.

Their cell bodies areTheir cell bodies are in thein the Dorsal Root Dorsal Root Ganglia.Ganglia.

Carry :Carry : 1.Efferent neurons1.Efferent neurons

(Lower Motor Neurons) (Lower Motor Neurons) Their cell bodies are Their cell bodies are

located in the Spinal located in the Spinal Gray matter. Gray matter.

2.Preganglionic 2.Preganglionic Autonomic neurons.Autonomic neurons.

Spinal Nerves areSpinal Nerves are Mixed.Mixed.

Contain: Contain: Both Afferent and Both Afferent and

Efferent fibers.Efferent fibers. Each spinal nerve is Each spinal nerve is

divided into divided into Dorsal Dorsal andand Ventral Ventral

Rami.Rami.

Dorsal RamusDorsal Ramus : : Thin. Thin. Supplies muscles and skin Supplies muscles and skin

of the back.of the back. Ventral RamusVentral Ramus : : Larger.Larger. Supplies muscles and skin Supplies muscles and skin

of the Front of the body of the Front of the body and limbs.and limbs.

Connected to theConnected to the Sympathetic ChainSympathetic Chain by the by the White and Grey Rami.White and Grey Rami.

The spinal cord isThe spinal cord is Segmented.Segmented.

In the LivingIn the Living The approximate level of The approximate level of

the segments is the segments is identified by theidentified by the Posterior SpinousPosterior Spinous Process Process of the vertebraeof the vertebrae..

Cervical SegmentsCervical Segments:: OneOne spinespine HigherHigher than their than their

corresponding vertebrae.corresponding vertebrae. C7 Segment is adjacent to C7 Segment is adjacent to

C6 Vertebra.C6 Vertebra. Thoracic segmentsThoracic segments : : TwoTwo spinesspines HigherHigher . . Lumbar segments :Lumbar segments : Three- FourThree- Four spinesspines HigherHigher..

Cervical RegionCervical Region : : Cervical segments lie Cervical segments lie

adjacent to their adjacent to their correspondingcorresponding Vertebral Vertebral Bodies.Bodies.

1-7 C : 1-7 C : Above the Above the Upper SevenUpper Seven Cervical Vertebrae.Cervical Vertebrae.

C8 : C8 : Below 7Below 7thth Cervical Vertebra.Cervical Vertebra.

T1 and the rest of T1 and the rest of the nerves:the nerves: Below Below their Corresponding their Corresponding Vertebrae.Vertebrae.

The The Lumbar Lumbar andand Sacral Sacral nerves take an nerves take an Oblique Course to Oblique Course to reach the reach the intervertebral intervertebral foramina.foramina.

The resulting leash of The resulting leash of nerve roots forms thenerve roots forms the Cauda Equina.Cauda Equina.

Pia MaterPia Mater The inner most layerThe inner most layer. . A delicate ,vascular A delicate ,vascular

membrane.membrane. It is It is CloselyClosely applied to applied to

the surface of the the surface of the spinal cord. spinal cord.

It extends inferiorly as It extends inferiorly as the the FilumFilum TerminaleTerminale..

A flat membrane formed A flat membrane formed from from Pia Mater.Pia Mater.

Extension:Extension: Along a midway line Along a midway line

between the dorsal and between the dorsal and ventral nerve rootsventral nerve roots..

Laterally to adhere to Laterally to adhere to the Arachnoid and Durathe Arachnoid and Dura. .

The spinal cord is The spinal cord is suspended in the middle suspended in the middle of the dural sheath.of the dural sheath.

Arachnoid:Arachnoid: A a fibrous membrane. A a fibrous membrane. It It LooselyLoosely covers the covers the

spinal cord.spinal cord. Dura:Dura: A dense, strong A dense, strong

fibrous membrane.fibrous membrane. It is continuous It is continuous

superiorly with the superiorly with the Meningeal layer of the Meningeal layer of the Cranial Dura. Cranial Dura.

They extend along They extend along Each Nerve Root Each Nerve Root and become and become continuouscontinuous with itswith its EpineuriumEpineurium..

InferiorlyInferiorly They extend to theThey extend to the

22ndnd sacral vertebra sacral vertebra..

EpiduralEpidural Separates Dural Sheath from Separates Dural Sheath from

the Vertebral Canal. the Vertebral Canal. Contains theContains the Internal Internal

Vertebral Venous PlexusVertebral Venous Plexus.. SubduralSubdural A thin space. A thin space. Separates Dura from Separates Dura from

Arachnoid.Arachnoid.

SubarachnoidSubarachnoid ContainsContains Cerebro Cerebro

Spinal Fluid.Spinal Fluid. TerminatesTerminates At the level ofAt the level of S2S2

Held in position by :Held in position by : Laterally Laterally : : DenticulateDenticulate

Ligament.Ligament. Inferiorly Inferiorly : : Filum Filum

TerminaleTerminale.. The spinal cord is The spinal cord is

Cushioned againstCushioned against TraumaTrauma by: by: Cerebrospinal Fluid.Cerebrospinal Fluid.

SiteSite : : Subarachnoid SpaceSubarachnoid Space

((L2-L3L2-L3 or or L3 –L4L3 –L4).). Not AllowedNot Allowed in Children in Children.. IndicationsIndications:: 1. 1. Diagnostic purposesDiagnostic purposes.. 2. 2. Radiological studyRadiological study

((MyelographyMyelography).).

Injection ofInjection of AAnaestheticsnaesthetics into into the the Epidural SpaceEpidural Space It is for Surgical It is for Surgical Procedures as in Procedures as in Labour. Labour.

1. 1. Anterior spinal Anterior spinal artery.artery.

2. 2. Posterior Posterior spinal Arteriesspinal Arteries..

3. 3. Radicular Radicular Arteries.Arteries.

A single Y shaped artery. A single Y shaped artery. ArisesArises from : from :Vertebral arteryVertebral artery

at the level of the medulla.at the level of the medulla. Supplies the cord at theSupplies the cord at the

Cervical Level.Cervical Level. It isIt is most vulnerablemost vulnerable in the in the

anterior part of the cordanterior part of the cord particularly in theparticularly in the Thoracic Thoracic Segment.Segment.

Its OcclusionIts Occlusion causescauses Acute Acute Thoracic Syndrome Thoracic Syndrome with with Paraplegia and Paraplegia and Incontinence.Incontinence.

Two arteries.Two arteries. Arise from Arise from . . VertebralVertebral Or Or Posterior Inferior Posterior Inferior

CerebellarCerebellar arteries. arteries. Spinal Arteries (Anterior Spinal Arteries (Anterior

&Posterior) are&Posterior) are Insufficient aloneInsufficient alone to to supply the cord Below supply the cord Below the the Cervical LevelCervical Level. .

Origin from following Origin from following arteries :arteries :

1. 1. Ascending cervical Ascending cervical 2. Intercostal. 2. Intercostal.

3. Lumbar. 3. Lumbar. They share in the They share in the

arterial supply of thearterial supply of the cord cord Below the Cervical Below the Cervical Level.Level.

They They AnastomoseAnastomose freely freely with the Spinal with the Spinal Arteries. Arteries.

Artery of Artery of Adamkiewicz.Adamkiewicz. It may arise from:It may arise from:

Intercostal or Lumbar Intercostal or Lumbar arteries.arteries.

It suppliesIt supplies Lower half ofLower half of the spinal the spinal

cord (cord (T8 –L3T8 –L3). ). These areThese are Vulnerable Vulnerable

Segments.Segments. OcclusionOcclusion of the artery of the artery

may cause Muscle may cause Muscle weakness andweakness and Paralysis.Paralysis.

Six Six Longitudinal Interconnecting Longitudinal Interconnecting Venous Channels.Venous Channels.

(1) (1) Anterior Anterior and and PosteriorPosterior SpinalSpinal veins in the midline.veins in the midline.

(2) (2) AnterolateralAnterolateral and and Posterolateral Posterolateral paired veins paired veins situated near the lines of situated near the lines of attachment of the attachment of the

Ventral and Ventral and Dorsal rootsDorsal roots.. (3) (3) AnteriorAnterior and and Posterior Posterior

Radicular VRadicular Veins.eins.

(4) (4) Internal Internal vertebral venous vertebral venous plexusplexus in the in the Epidural SpaceEpidural Space..

(5) (5) External External Vertebral Venous Vertebral Venous Plexus.Plexus.

(6) (6) Ascending Ascending Lumbar, Azygos and Lumbar, Azygos and Hemiazygos Veins.Hemiazygos Veins.

The spinal nerve roots can be The spinal nerve roots can be injured by Compression ofinjured by Compression of Prolapsed Intervertebral Discs. Prolapsed Intervertebral Discs.

It is manifested by:It is manifested by: 1. 1. ParaesthesiaParaesthesia (tingling(tingling

sensations).sensations). 2.2. Weakness and wastingWeakness and wasting of of

the muscles.the muscles. 3. 3. Numbness of the skin Numbness of the skin

corresponding to the corresponding to the dermatomal distribution.dermatomal distribution.

4. Loss of Tendon Reflexes.4. Loss of Tendon Reflexes.

(A) (A) CervicalCervical Pain in the neck radiating Pain in the neck radiating

to the arm and handto the arm and hand.. (B) (B) LumbarLumbar 1.1. BackBack pain.pain. 2. Sciatica ( radiation of 2. Sciatica ( radiation of

pain into the legs) .pain into the legs) . A large A large LumbosacralLumbosacral

prolapsed discprolapsed disc can cause can cause paralysis of the bladder and paralysis of the bladder and incontinence.incontinence.