Neuro Anatomy Nerve Trunks
-
Upload
dr-kazuhito-mori -
Category
Documents
-
view
1.179 -
download
0
description
Transcript of Neuro Anatomy Nerve Trunks
Nerve Trunks & DivisionsLecture: Day 22
Kazuhito Mori, M.Sc., Ph.D.Southwestern University
Matias Hipolito Aznar MemorialCollege of Medicine
Neuro-Anatomy Class Presentation
Plait du Jour: Main Dish of the Day
1. Identify Anterior Primary Ramus & Posterior Primary Ramus
2. Name Plexus of Nerves associated with Anterior Rami Cervical Plexus Brachial Plexus Lumbar Plexus Sacrococcygeal Plexus
Tranks & Divisions 1: Objectives
Trunks & Divisions 2: Definition
1. Trunks The Main Body of an Anatomical Part (as a
Nerve or Blood Vessel) that divides into Branches
2. Plexus A Network of Anastomosing or Interlacing
Nerves or Blood Vessels Nerve Plexus = a network of Intersecting
Nerves consisted of sets of Spinal Nerves that serve the same area of the body as 1 Large Grouped Nerve
Nervous System
CentralNervous System
PeripheralNervous System
Cranial Nerves(12 pairs)
Spinal Nerves(31 pairs)
Cervical, ThoracicLumbar, Sacral
Coccygeal
Trunks & Plexus 3Location
A)A) exit the exit the Vertebral ColumnVertebral Column thru thru Intervertebral Intervertebral ForaminaForamina
B)B) arise from the arise from the Spinal CordSpinal Cord first as first as RootletsRootlets①① Rootlets have Rootlets have Anterior & Anterior &
Posterior portionPosterior portion②② Anterior Rootlets converge Anterior Rootlets converge
to form to form Anterior (Ventral) Anterior (Ventral) RootRoot
③③ Posterior Rootlets converge Posterior Rootlets converge to form to form Posterior (Dorsal) Posterior (Dorsal) RootRoot
④④ Anterior Root = Anterior Root = Motor, Motor, EfferentEfferent
⑤⑤ Posterior Root = Posterior Root = Sensory, Sensory, AfferentAfferent
⑥⑥ A Mixed Spinal NerveA Mixed Spinal Nerve (Anterior & Posterior Roots)(Anterior & Posterior Roots)
Trunks & Plexus4: Brief Recap / Facts on Spinal NervesSpinal Nerves…
A)
B)
A Mixed Spinal Nerve Divides into 2 Rami
1. Anterior (=Ventral) Primary Ramus
2. Posterior (=Dorsal) Primary Ramus
Anterior (Ventral) Ramus & Posterior (Dorsal) Ramus
1. Dorsal Primary Ramus Lateral Division Medial Division
2. Ventral Primary Ramus
Ventral Primary Rami form Nerve Plexuses
a. Muscular Branch
b. Lateral Cutaneous Branch
c. Anterior Cutaneous Branch
d. White Ramus Communicans: General Visceral Afferents General Visceral Efferents (P
reganglionic Sympathetic)
e. Gray Ramus Communicans: (Postganglionic Sympathetic)
a.
b.
c.
d.
e.
End of Rami, Go to Plexus
Nerve PlexusNerve Plexus Plexus1: OverviewPlexus1: Overview
From From Ventral Primary RamusVentral Primary Ramus to to PlexusPlexus Cervical PlexusCervical Plexus - the Head, Neck - the Head, Neck
& Shoulders & Shoulders Brachial PlexusBrachial Plexus - the Chest, Shoul - the Chest, Shoul
ders, Arms & Hands ders, Arms & Hands Lumbar PlexusLumbar Plexus - the Back, Abdom - the Back, Abdom
en, Groin, Thighs, Knees, & Calveen, Groin, Thighs, Knees, & Calves s
Sacral PlexusSacral Plexus - the Pelvis, Buttock- the Pelvis, Buttocks, Genitals, Thighs, Calves, & Feet s, Genitals, Thighs, Calves, & Feet
Coccygeal PlexusCoccygeal Plexus Lumbar & Sacral plexus are sometLumbar & Sacral plexus are somet
imes referred to as the “imes referred to as the “LumbosacLumbosacral plexusral plexus” since they’re interconne” since they’re interconnectedcted
The nerves that serve The nerves that serve the Chestthe Chest ar are the only ones e the only ones that do not originatthat do not originate from a plexuse from a plexus
Ventral Primary Ramus to PlexusVentral Primary Ramus to Plexus Plexus2: GeneralsPlexus2: Generals
Upper LimbsUpper Limbs Cervical PlexusCervical Plexus - C1, C2, C3, C4, C5 - C1, C2, C3, C4, C5 Brachial PlexusBrachial Plexus - Formed by - Formed by CCervical & ervical & ThThoracic oracic
Nerves & supplying Nerves & supplying ArmArm & & parts ofparts of ShoulderShoulder
Lower LimbsLower Limbs Lumbar PlexusLumbar Plexus --- L1, L2, L3, L4 (Ventral Branches) --- L1, L2, L3, L4 (Ventral Branches) Sacral PlexusSacral Plexus --- --- L4L4, , L5L5, S1, S2, S3; supplying , S1, S2, S3; supplying Pelvic Pelvic
RegionRegion & & Lower LimbsLower Limbs Coccygeal PlexusCoccygeal Plexus - A small Plexus by - A small Plexus by S5S5 & &CocCoccygealcygeal (Lumbosacral Plexus(Lumbosacral Plexus - by Ventral Divisions of the - by Ventral Divisions of the
LLumbar, umbar, SSacral & acral & CocCoccygeal Nerves; supplying cygeal Nerves; supplying Lower Lower LimbsLimbs & & PerineumPerineum & & Coccygeal AreaCoccygeal Area))
PLEXUS• At the root of the Limbs, the Anterior Rami combine to form complicated Nerve Plexuses• The Cervical & Brachial Plexuses are found at the root of Upper Limbs• The Lumbar & Sacral Plexuses are found at the root of the Lower Limbs
End of Generals
Cervical PlexusCervical Plexus PlexusC1PlexusC1
formed by the formed by the Anterior DivisionsAnterior Divisions of the of the first 4 Cervical Nervesfirst 4 Cervical Nerves; ; C1-3 form C1-3 form LoopsLoops; ; Ansa CervicularisAnsa Cervicularis Covered by the Covered by the Sternocleidomastoid MuscleSternocleidomastoid Muscle The anterior rami are joined by connecting branches that form loops located in front oThe anterior rami are joined by connecting branches that form loops located in front o
f the origin of f the origin of Levator ScapulæLevator Scapulæ & & Scalenus MediusScalenus Medius divided into 2 Branches; divided into 2 Branches;
CutaneousCutaneous Branches Branches Muscular Muscular BranchesBranches
Cervical PlexusCervical Plexus Plexus C2Plexus C2
Cutaneous BranchesCutaneous Branches
– Lesser Occipital N.Lesser Occipital N. C2 C2– Great Auricular N.Great Auricular N. C2,3 C2,3– Transverse Cervical N.Transverse Cervical N.
C2,3 C2,3– Supraclavicular N. Supraclavicular N. C3,4 C3,4
Cutaneous BranchesCutaneous Branches
Cervical PlexusCervical Plexus Plexus C3Plexus C3
SegmentalSegmental Prevertebral MusclePrevertebral Muscle Levator ScapulaeLevator Scapulae
Ansa Cervicalis Ansa Cervicalis (C1-3)(C1-3) OmohyoidOmohyoid SternohyoidSternohyoid SternothyroidSternothyroid
C1 via XII (C1 via XII (hypoglossalhypoglossal)) GeniohyoidGeniohyoid ThyrohyoidThyrohyoid
Phrenic NervePhrenic Nerve Diaphragm Diaphragm (Respiration)(Respiration)
Muscular BranchMuscular Branch
Brachial PlexusBrachial Plexus Plexus B1Plexus B1
formed by the formed by the Anterior DivisionsAnterior Divisions of the Lower 4 Cervical Nerves ( of the Lower 4 Cervical Nerves (C5, 6, C5, 6, 7, 87, 8) & the greater part of the ) & the greater part of the Anterior DivisionAnterior Division of of T1T1
C4 usually gives a branch to C5 & T1 frequently receives 1 from the T2 C4 usually gives a branch to C5 & T1 frequently receives 1 from the T2 ((C4-C5C4-C5 / / T1-T2T1-T2))
extends from the Lower Part of the side of the neck to the extends from the Lower Part of the side of the neck to the AxillaAxilla. Their n. Their nerves are erves are Nearly Equal in SizeNearly Equal in Size BUTBUT their Mode of Communication their Mode of Communication VARYVARY
The most constant arrangement are The most constant arrangement are C5C5 & & C6C6; forming ; forming Upper TrunkUpper Trunk imm immediately after the ediately after the Intervertebral ForaminaIntervertebral Foramina
C8 & T1C8 & T1 unite to form unite to form Lower TrunkLower Trunk C7C7 runs out alone runs out alone as the as the Middle TrunkMiddle Trunk
Brachial PlexusBrachial Plexus Plexus B2Plexus B2
3 Trunks3 Trunks——UpperUpper, , MidMiddledle & & Lower Lower are formeare formed as they pass under thd as they pass under the Clavicle, each trunk se Clavicle, each trunk splits into plits into AnteriorAnterior && PoPosterior sterior DivisionsDivisions
The The Anterior DivisionAnterior Divisionss of the of the UpperUpper & & MiddlMiddle Trunkse Trunks form “ form “Lateral Lateral CordCord“ on the Lateral Si“ on the Lateral Side of the 2nd part of thde of the 2nd part of the Axillary Arterye Axillary Artery
The The Anterior DivisionAnterior Division of the of the Lower TrunkLower Trunk pa passes down on the sses down on the MediMedial Sideal Side of the of the Axillary Axillary ArteryArtery as “ as “Medial CorMedial Cordd““
The The Posterior DivisionsPosterior Divisions of All 3 Trunks form the of All 3 Trunks form the Posterior CordPosterior Cord behind behind the 2nd portion of the the 2nd portion of the AAxillary Arteryxillary Artery
Brachial PlexusBrachial Plexus PlexusB3PlexusB3
Anatomical RelationsAnatomical Relations In the neck, the plexus lies in the In the neck, the plexus lies in the Posterior Posterior
TriangleTriangle covered by the skin, covered by the skin, PlatysmaPlatysma & & DDeep Fasciaeep Fascia
crossed by the crossed by the Supraclavicular NervesSupraclavicular Nerves, the , the Inferior Belly of the Inferior Belly of the OmohyoidOmohyoid
crossed by the crossed by the External Jugular VeinExternal Jugular Vein & the & the Transverse Cervical ArteryTransverse Cervical Artery
emerges between the Scaleni Anterior & Memerges between the Scaleni Anterior & Medius; its Upper Part lies edius; its Upper Part lies aboveabove the 3rd part the 3rd part of the Subclavian Artery, while Lower Trunk of the Subclavian Artery, while Lower Trunk (C8 & T1) is (C8 & T1) is behindbehind the artery the artery
3rd Part of Subclavian Artery3rd Part of Subclavian Artery Above ---Above --- Scaleni Anterior & MediScaleni Anterior & Medi
usus Behind --- Behind --- Lower Trunk (C8 & T1)Lower Trunk (C8 & T1)
passes passes behindbehind the Clavicle, the Subclavius the Clavicle, the Subclavius & the Transverse Scapular Vessels& the Transverse Scapular Vessels
lies lies onon the 1st digitation of the Serratus Ant the 1st digitation of the Serratus Anterior & the Subscapulariserior & the Subscapularis
In the axilla it is placed In the axilla it is placed laterallateral to the 1st por to the 1st portion of the Axillary Artery, tion of the Axillary Artery, surroundssurrounds the 2nd the 2nd part of the Arterypart of the Artery
gives off its terminal branches to the Upper gives off its terminal branches to the Upper Limb at the Lower part of the AxillaLimb at the Lower part of the Axilla
Lumbo-Sacral Plexus
Formed by Formed by Ventral Ventral DivisionsDivisions of of LLumbar Nervesumbar Nerves SSacral Nervesacral Nerves CocCoccygeal Nervescygeal Nerves
SuppliesSupplies Lower LimbsLower Limbs Perineum AreaPerineum Area Coccygeal AreaCoccygeal Area
Lumbar Plexus formed by the loops of communication betwe
en the Anterior Divisions of L1, L2, L3 & the greater part of L4
L1 often receives a branch from T12 situated in the Posterior Part of the Psoas Major in front of the Transverse Processes of the Lumbar Vertebræ
This Plexus DIFFERS from the Brachial Plexus in NOT forming an intricate interlacement, BUT the several nerves of distribution arise from 1 or more of Spinal Nerves
L1 receiving a twig from T12 splits into Upper & Lower Branches
Upper & Larger Branch Iliohypogastric Nerves Ilioinguinal Nerves
Lower & Smaller Branch Genitofemoral Nerve with L2
<L2, L3, L4> Ventral Divisions --- Obturator Nerve Dorsal Divisions
Smaller Branch (L2 & L3) Lateral Femoral Cutaneous Nerve
Larger Branch (L2 & L3) Femoral Nerve with L4 Dorsal Div.
If The Accessory Obturator exists, it is formed by 2 Small branches given by L3 & L4
Sacral PlexusSacral Plexus formed byformed by
Lumbosacral TrunkLumbosacral Trunk L4L4 (partially) (partially) L5L5 (Anterior Division) (Anterior Division)
S1S1 (Anterior Division) (Anterior Division) S2S2 (Anterior Division) partially (Anterior Division) partially S3S3 (Anterior Division) (Anterior Division)
appears at the Medial Margin of the appears at the Medial Margin of the Psoas MajPsoas Majoror & runs downward over the & runs downward over the Pelvic BrimPelvic Brim to join to join S1S1
S3S3 (Anterior Division) (Anterior Division) Upper Branches ---Upper Branches --- Sacral PlexSacral Plex
usus Lower Branches ---Lower Branches --- Pudendal PlPudendal Pl
exusexus The nerves of this Plexus converge toward the The nerves of this Plexus converge toward the
Lower part of the Lower part of the Greater Sciatic ForamenGreater Sciatic Foramen & for & form a flattened band from the Anterior & Posteriom a flattened band from the Anterior & Posterior surfaces where several branches arise. The br surfaces where several branches arise. The band itself continues as the and itself continues as the Sciatic NerveSciatic Nerve
Sciatic NerveSciatic Nerve on the Back of Thigh splits;on the Back of Thigh splits; Tibial NervesTibial Nerves Common Peroneal NervesCommon Peroneal Nerves
These 2 nerves sometimes arise separately froThese 2 nerves sometimes arise separately from the Plexus; their independence can always bm the Plexus; their independence can always be shown in Dissectione shown in Dissection
Coccygeal PlexusCoccygeal Plexus
• Coccygeal Plexus– S5 receiving S4 (Communic
ating Filament)– Coccygeal Nerve
• Anococcygeal Nerves originate from the plexus; consist of a few fine filaments piercing the Sacrotuberous Ligament to supply the skin on the Coccyx region
Clinical Consideration: Plexus Disorders
Plexuses, interwoven nerve fibres from different spinal nerves could be damaged by Injury, Tumors, Blood Collections or Autoimmune Reactions
Pain, Weakness & Loss of Sensation occur in Upper or Lower Limb
EMG & Evoked Responses help to locate the damage
MRI locates the damage & identifies the cause
Treating the disorder causing the problem could improve nerve functions
Is Your Brachial Plexus OK, Maria?
You should now be able to …
1. Differentiate Anterior & Posterior Primary Rami
2. Name Plexus of Nerves associated with Anterior Ramus as well as their Anatomical Formation
Cervical Plexus Brachial Plexus Lumbar Plexus Sacrococcygeal Plexus
Salamat !
Closing Slide: Before You Go Home
References Cited
Clinical Neuroanatomy 6th ed., Richard S. Snell, MD, PhD Clinical Anatomy (By Regions) 8th ed., Richard S. Snell, MD, PhD Clinical Anatomy (By Systems), Richard S. Snell, MD, PhD Atlas of Human Anatomy 4th ed., Frank H. Netter, MD Clinically Oriented Anatomy 5th ed., K.L. Moore, PhD, FIAC, FRSM Gray’s Anatomy of the Human Body, Philadelphia: Lea & Febiger Fundamental Neuroscience 3rd ed., Duane E. Haines, PhD Webster’s New Explorer Medical Dictionary, Federal Street Press National Institute of Neurological Disorders & Stroke (NINDS), Bethesda, M
A, U.S.A.