THE GROSS THE GROSS APPEARANCE OF APPEARANCE OF

SPINAL CORDSPINAL CORD

Lecturer: Emmaruth B. Lecturer: Emmaruth B. Bautista, PTRPBautista, PTRP

EXTERNAL EXTERNAL ANATOMYANATOMY

External AnatomyExternal Anatomy

Length: 42-45 cmLength: 42-45 cm Roughly cylindricalRoughly cylindrical Superiorly: foramen magnumSuperiorly: foramen magnum Inferiorly: adult- lower border of 1Inferiorly: adult- lower border of 1stst

vertebravertebra Young child: upper border of 3Young child: upper border of 3rdrd

lumbar vertebralumbar vertebra Occupies upper 2/3 of vertebral canalOccupies upper 2/3 of vertebral canal Covered by 3 meninges ( PAD )Covered by 3 meninges ( PAD )

EnlargementsEnlargements

Fusiformly enlarged:Fusiformly enlarged: Cervical enlargementCervical enlargement

– BRACHIAL PLEXUSBRACHIAL PLEXUS

Lumbar enlargementLumbar enlargement– LUMBOSACRAL PLEXUSLUMBOSACRAL PLEXUS

CSF- further protects SCCSF- further protects SC Subarachnoid spaceSubarachnoid space CONUS MEDULLARIS- tapered end of CONUS MEDULLARIS- tapered end of

SCSC FILUM TERMINALE- prolongation of FILUM TERMINALE- prolongation of

pia materpia mater– Descends to attach to the posterior Descends to attach to the posterior

surface of coccyxsurface of coccyx

SegmentsSegments

CervicalCervical ThoracicThoracic LumbarLumbar SacralSacral CoccygealCoccygeal

Longitudinal DivisionsLongitudinal Divisions

Anterior median fissureAnterior median fissure Posterior median sulcusPosterior median sulcus Ventrolateral sulcusVentrolateral sulcus Dorsal lateral sulcusDorsal lateral sulcus

Spinal roots and NervesSpinal roots and Nerves

31 pairs of spinal nerves.31 pairs of spinal nerves.

– Ventral root: MOTOR ROOTSVentral root: MOTOR ROOTS– Dorsal root: SENSORY ROOTSDorsal root: SENSORY ROOTS

DORSAL ROOT GANGLIONDORSAL ROOT GANGLION Gives rise to peripheral & central nerve Gives rise to peripheral & central nerve

fibersfibers

Ventral RootVentral Root

Biceps - C5/6 Biceps - C5/6 Brachioradialis - C5/6 Brachioradialis - C5/6 Triceps - C7 (C6-8) Triceps - C7 (C6-8) Finger flexors - C8 (C7-T1) Finger flexors - C8 (C7-T1) Knee - L3 (L2-L4) Knee - L3 (L2-L4) Ankle - S1 (L5-S2)Ankle - S1 (L5-S2)

Dorsal RootDorsal Root Clinically important dermatomes Clinically important dermatomes C2 and C3 - Posterior head and neck C2 and C3 - Posterior head and neck C4 and T2 - Adjacent to each other in the C4 and T2 - Adjacent to each other in the

upper thorax upper thorax Nipple - T4 or T5 Nipple - T4 or T5 Umbilicus - T10 Umbilicus - T10 Upper extremity Upper extremity

– C5 - Anterior shoulder C5 - Anterior shoulder – C6 - Thumb C6 - Thumb – C7 - Index and middle fingers C7 - Index and middle fingers – C 7/8 - Ring finger C 7/8 - Ring finger – C8 - Little finger C8 - Little finger – T1 - Inner forearm T1 - Inner forearm – T2 - Upper inner arm T2 - Upper inner arm – T2/3 - AxillaT2/3 - Axilla

Dorsal RootDorsal Root

Lower extremity Lower extremity – L1 - Anterior upper-inner thigh L1 - Anterior upper-inner thigh – L2 - Anterior upper thigh L2 - Anterior upper thigh – L3 - Knee L3 - Knee – L4 - Medial malleolus L4 - Medial malleolus – L5 - Dorsum of foot L5 - Dorsum of foot – L5 - Toes 1-3 L5 - Toes 1-3 – S1 - Toes 4,5; lateral malleolusS1 - Toes 4,5; lateral malleolus

S3/C1 - AnusS3/C1 - Anus

Branches of Spinal NervesBranches of Spinal Nerves

Posterior primary division.Posterior primary division. Anterior primary division.Anterior primary division. Rami communicantes.Rami communicantes. Recurrent meningeal branches.Recurrent meningeal branches.

INTERNAL INTERNAL ANATOMYANATOMY

Gray MatterGray Matter

H-shaped pillarH-shaped pillar HORN-each arm of the H HORN-each arm of the H resulting in two anterior horns and resulting in two anterior horns and

two posterior horns. two posterior horns. gray commissure- The connecting gray commissure- The connecting

middle portion is called middle portion is called Related to the amount of muscle Related to the amount of muscle

innervated at the level.innervated at the level.

The gray matter can be divided into The gray matter can be divided into 10 laminae/layers or into 4 parts: 10 laminae/layers or into 4 parts:

anterior or ventral horn (ie, motor anterior or ventral horn (ie, motor neurons; laminae VIII, IX, and part of neurons; laminae VIII, IX, and part of VII), VII),

posterior or dorsal horn (ie, sensory posterior or dorsal horn (ie, sensory part; laminae I-VI), intermediate part; laminae I-VI), intermediate zones (ie, associate neurons; lamina zones (ie, associate neurons; lamina VII), and lateral horns (ie, part of the VII), and lateral horns (ie, part of the intermediate zone, present in the intermediate zone, present in the thoracic and lumbar segments, thoracic and lumbar segments, where sympathetic neurons are where sympathetic neurons are located).located).

White MatterWhite Matter

Divisions:Divisions:– Anterior columnAnterior column– Posterior columnPosterior column– Lateral columnLateral column

Consists of a mixture of nerves, Consists of a mixture of nerves, neuroglia, and blood vessels.neuroglia, and blood vessels.

Anterior ColumnAnterior Column

Contains alpha and gamma motor Contains alpha and gamma motor neurons.neurons.

3 groups:3 groups:GROUPGROUP

MedialMedial

CentralCentral

LateralLateral

INNERVATIONINNERVATION

Mm of trunk, neck, Mm of trunk, neck, abdomen & intercostalsabdomen & intercostals

Phrenic, accessory, & Phrenic, accessory, & lumbosacrallumbosacral

Mm of the limbsMm of the limbs

Posterior ColumnPosterior Column

Reaches almost to the posterolateral Reaches almost to the posterolateral sulcus.sulcus.

Nerve cell groupsNerve cell groups– Substantia gelatinosa groupsSubstantia gelatinosa groups– Nucleus propriusNucleus proprius– Nucleus dorsalis ( Clarkes’s Column )Nucleus dorsalis ( Clarkes’s Column )– Visceral afferent nucleus Visceral afferent nucleus

Substantia GelatinosaSubstantia Gelatinosa

Located at apex of posterior gray Located at apex of posterior gray columncolumn

Pain & temperaturePain & temperature Great amount of Substance PGreat amount of Substance P

Nucleus PropriusNucleus Proprius

Anterior to the substantia gelatinosa.Anterior to the substantia gelatinosa. Main bulk of posterior column.Main bulk of posterior column. Receives from posterior WHITE Receives from posterior WHITE

column.column. PROPRIOCEPTION, 2 PT. PROPRIOCEPTION, 2 PT.

DISCRIMINATION, VIBRATIONDISCRIMINATION, VIBRATION

Nucleus DorsalisNucleus Dorsalis

Clark’s ColumnClark’s Column Base of the posterior gray columnBase of the posterior gray column From C8-L4 segmentFrom C8-L4 segment Propioceptive endingsPropioceptive endings ( mm spindle & tendon spindle )( mm spindle & tendon spindle )

Visceral Afferent NucleusVisceral Afferent Nucleus

Lateral to the nucleus dorsalis.Lateral to the nucleus dorsalis. From T1-L3 segments.From T1-L3 segments. Receives visual afferent information.Receives visual afferent information.

LaminaeLaminaeLaminLaminaa

DescriptionDescription

II Responds to noxious stimuliResponds to noxious stimuli

IIII SG; High concentrations of Substance SG; High concentrations of Substance P.P.

III & IVIII & IV Nucleus PropriusNucleus Proprius

VV Responds to noxious stimuliResponds to noxious stimuli

LaminaeLaminaeVIVI Deepest layer of the dorsal horn; Deepest layer of the dorsal horn;

responds to mechanical signals from responds to mechanical signals from joints & skinjoints & skin

VIIVII Anterior & posterior column; Anterior & posterior column; intermediolateral nucleus in the intermediolateral nucleus in the thoracic & upper lumbar regionsthoracic & upper lumbar regions

VIII & VIII & IXIX

Medial & lateral nuclei of the anterior Medial & lateral nuclei of the anterior columncolumn

XX Around the central canalAround the central canal