Exercise 19Exercise 19

Spinal Cord & Spinal Cord & Spinal NervesSpinal Nerves

http://www.georgiapainphysicians.com/downloads/m1_slides/4.%20Spinal%20cord%20junctions.jpg

Figure 19.1a Gross structure of the spinal cord, dorsal view.

Cervicalspinal nervesC1-C8

Conus medullaris

Cauda equina

Thoracicspinal nervesT1- T12

Lumbarspinal nervesL1- L5

Sacral spinal nervesS1- S5

Filumterminale

Coccygeal spinal nerveCo1

The spinal cord and its nerve roots, withthe bony vertebral arches removed. The duramater and arachnoid mater are cut openand reflected laterally.

Spinal CordSpinal CordExtends from Extends from

Foramen Foramen magnum magnum L1-L2 @ L1-L2 @ conus conus medullarismedullaris

Filum terminaleFibrous extension of meninges, blends into coccygeal ligament

Attaches to coccyx

Cauda equina

“horse’s tail”

lumbar & sacral nerves’ long ventral & dorsal roots…

Figure 19.1a Gross structure of the spinal cord, dorsal view.

Cervicalspinal nervesC1-C8

Conus medullaris

Cauda equina

Thoracicspinal nervesT1- T12

Lumbarspinal nervesL1- L5

Sacral spinal nervesS1- S5

Filumterminale

Coccygeal spinal nerveCo1

The spinal cord and its nerve roots, withthe bony vertebral arches removed. The duramater and arachnoid mater are cut openand reflected laterally.

Medulla oblongata Medulla oblongata (brainstem)(brainstem)

Conus medullarisConus medullaris

tapered inferior endtapered inferior end

Spinal Cord—Similar to BrainSpinal Cord—Similar to BrainGray matterGray matter

Central in spinal cordCentral in spinal cord

White matterWhite matterExternal in spinal cordExternal in spinal cord

Cerebrospinal Fluid (CSF)Cerebrospinal Fluid (CSF)Fills meningesFills meninges

Proteins, nutrients—Proteins, nutrients—continuous circulationcontinuous circulation

• Meninges: surrounding membranesMeninges: surrounding membranes– Pia mater: innermostPia mater: innermost– Arachnoid: middleArachnoid: middle– Dura mater: outermostDura mater: outermost

• Extend beyond the spinal cordExtend beyond the spinal cord• Continuous with meninges of brainContinuous with meninges of brain• Physical stability, shock absorptionPhysical stability, shock absorption

Spinal duramater

Arachnoidmater

Pia mater

Figure 19.2a Anatomy of the human spinal cord.

Epidural space(contains fat)

(contains CSF)

Spinalnerve

Pia materArachnoid materDura mater

Spinal meninges

Bone ofvertebra

Dorsal rootganglion

Bodyof vertebra

Spinal Cord—Similar to BrainSpinal Cord—Similar to Brain

Epidural spacebetween dura mater & walls of vertebrae

areolar tissue, blood vessels, adipose tissue (protection)

Figure 19.5 Human spinal nerves.

Cervical plexusC1 – C5

Brachial plexusC5 – T1

Cervicalenlargement

Intercostalnerves

Lumbarenlargement

Lumbar plexusL1 – L4

Sacral plexusL4 – S4

Cauda equina CoccygealnerveCo1

SacralnervesS1 – S5

LumbarnervesL1 – L5

ThoracicnervesT1 – T12

CervicalnervesC1 – C8

Spinal NervesSpinal NervesCervical spinal nervesCervical spinal nerves

Thoracic spinal nervesThoracic spinal nerves

Lumbar spinal nervesLumbar spinal nerves

Sacral spinal nervesSacral spinal nerves

Nerves for Divisions

• Sympathetic division – – thoracic & lumbar spinal nerves

(thoracolumbar)

• Parasympathetic division – – cranial nerves & sacral spinal nerves

(craniosacral);

Spinal Nerve PlexusesSpinal Nerve Plexuses

Cervical plexusCervical plexus

Brachial plexusBrachial plexus

Intercostal nerves (no plexus)Intercostal nerves (no plexus)

Lumbar plexusLumbar plexus

Sacral plexusSacral plexus

Cervical nervesCervical nerves

Thoracic nervesThoracic nerves

Lumbar nervesLumbar nerves

Sacral nervesSacral nerves

Figure 19.6 The cervical plexus.

Ventral rami

SegmentalbranchesHypoglossal

nerve (XII)

Lesser occipitalnerve

Greater auricularnerve

Transversecervical nerve

Ansa cervicalis

Accessory nerve (XI)

Phrenic nerve

Supraclavicularnerves

Ventralrami:

C1

C2

C3

C4

C5

Figure 19.7a The brachial plexus.

Dorsal scapular

Nerve tosubclavius

Suprascapular

Posteriordivisions

Cords

Lateral

Posterior

Medial

Axillary

Musculo-cutaneous

Radial

Median

Ulnar

C4

C5

C6

C7

C8

T1

Upper

Middle

Lower

Long thoracic

Medial pectoral

Lateral pectoral

Upper subscapular

Lower subscapular

Thoracodorsal

Medial cutaneousnerves of the armand forearm

Roots (ventral rami):

Anteriordivisions

Posteriordivisions

Trunks

Roots

Roots (rami C5 T1), trunks, divisions, and cords

Trunks

Figure 19.7c The brachial plexus.

Axillary nerve

Radial nerve

Musculo-cutaneousnerve

Ulnar nerveMediannerve

Humerus

Anteriordivisions

Posteriordivisions

Trunks

Roots

UlnaRadius

Radial nerve(superficialbranch)

Dorsal branchof ulnar nerve

Digital branchof ulnar nerve

Muscularbranch

Digitalbranch

Mediannerve

The major nerves of the upper limb

Superficial branchof ulnar nerve

Musculocutaneousnerve

Axillary nerve

Radial nerve

Median nerve

Biceps brachii

Ulnar nerve

Cadaver photo

Lateral cord

Posterior cord

Medialcord

Figure 19.8 The lumbar plexus (anterior view.)

Iliohypogastric

Ilioinguinal

Genitofemoral

Lateral femoralcutaneous

Obturator

Femoral

Lumbosacraltrunk

Iliohypogastric

Ilioinguinal

Femoral

Lateralfemoralcutaneous

Obturator

Anteriorfemoralcutaneous

Saphenous

L1

L2

L3

L4

L5

Ventral rami Ventral rami:

Figure 19.9b The sacral plexus (posterior view).

Superiorgluteal

Inferiorgluteal

Pudendal

Sciatic

Posteriorfemoralcutaneous

Commonfibular

Tibial

Sural (cut)

Deepfibular

Superficialfibular

Plantarbranches

Ventral rami

Sympathetic Chain Ganglia

• http://www.youtube.com/watch?v=fANkXK43xqk

Ganglia for Divisions

• sympathetic ganglia – – along spinal column (proximal to CNS)

• parasympathetic ganglia – – in or near the organs they control (distal to

CNS)

Figure 19.2b Anatomy of the human spinal cord.

Whitecolumns

Dorsal funiculus

Ventral funiculus

Lateral funiculus

Dorsal rootganglion

Spinal nerve

Dorsal root

Ventral root

Spinal duramater

Arachnoidmater

Pia mater

Central canal

Graymatter

Lateral horn

Ventral horn

Dorsal hornGray commissure

Spinal Cord AnatomySpinal Cord Anatomy

Each segment has:

Dorsal root

(axons of sensory neurons)

posterior

sensory, TO spinal cord

Dorsal root ganglia

cell bodies

Ventral root

(axons of motor neurons) anterior

motor, AWAY FROM cord

Sensory & Motor roots bound together---SPINAL NERVE (mixed nerve)

Spinal Cord AnatomySpinal Cord Anatomy

Central canalCentral canal

in center of spinal cordin center of spinal cord

continuous with continuous with “ventricles” in the brain“ventricles” in the brain—CSF circulation—CSF circulation

Spinal Cord Anatomy: Gray MatterSpinal Cord Anatomy: Gray Matter

Gray commissure: surrounds central canalGray commissure: surrounds central canal

Posterior (dorsal) hornPosterior (dorsal) horn

Lateral horn Lateral horn

Anterior (ventral) hornAnterior (ventral) horn

Spinal Cord Anatomy: White MatterSpinal Cord Anatomy: White Matter

Posterior (dorsal) white columnPosterior (dorsal) white column

Lateral white columnLateral white column

Anterior (ventral) white columnAnterior (ventral) white column

Figure 19.4 Cross section of the spinal cord (10).

Dorsalfuniculus

Dorsalhorn

Lateralfuniculus

Ventralhorn

Ventralfuniculus

Ventralmedianfissure

Dorsal mediansulcus

Review Figure 19.1

Table 19.1 Branches of the Cervical Plexus (See Figure 19.6)

Table 19.2 Branches of the Brachial Plexus (See Figure 19.7)

Table 19.3 Branches of the Lumbar Plexus (See Figure 19.8)

Table 19.4 Branches of the Sacral Plexus (See Figure 19.9)