Anatomy of Back Region

8/13/2019 Anatomy of Back Region

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Arteries of the Back

Artery Source Branches Supply to Notes

anteriorradicular

they arise asmultiple

branches ofseveral vessels

(vertebral,

posterior

intercostal,lumbar, and

lateral sacral

aa.)

they accompanythe ventral rootlets

to reach the spinalcord

meninges;spinal cord;

spinal nerve;ventral rootlets

anterior radicularaa. anastomose

with the anteriorspinal a.

anterior spinal contributionsreceived fromseveral arteries

(vertebral,

posterior

intercostal,subcostal,

lumbar, lateral

sacral aa.)

pial arterial plexus meninges;spinal cord;medulla (dorsal

motor nucleus

of cranial nerve

X, nucleusambiguus,

spinal accessory

nucleus andhypoglossal

nucleus)

anterior spinal a.anastomoses withthe anterior

radicular brs. of

the spinal rami of

the vertebral,posterior

intercostal,

subcostal, lumbarand lateral sacral

aa.

axillary subclavian a.(axillary a. is

the continuationof the

subclavian

lateral to the 1strib)

1st part: superiorthoracic a.; nd

part:thoracoacromial a.,

lateral thoracic a.;

!rd part: anteriorhumeral circumflex

a., posterior

humeral circumflex

a., subscapular a.

pectoral region,shoulder region

and upper limb

pectoralis minorm. crosses

anterior to theaxillary artery

and is used to

delineate the !parts mentioned

at left

cervical,ascending

inferior thyroida.

unnamed muscularbranches

deep muscles ofthe nec"

ascendingcervical a.ascends on the

anterior surface

of the anterior

scalene m. besidethe phrenic n.


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cervical, deep costocervicaltrun"


deep muscles ofthe posterior

nec"

deep cervical a.anastomoses with

the occipital a.

near the occipitalbone

cervical,

transverse

thyrocervical

trun"

unnamed muscular

branches, possiblythe dorsal scapular

a.

trape#ius muscle

and surroundingtissues

transverse

cervical a. givesrise to the dorsal

scapular a. $!%&

of the time

costocervical

trun"

subclavian a.,

nd part

deep cervical a.,

highest intercostala.

deep muscles of

the posteriornec"; posterior

ends of the first

intercostalspaces

costocervical

trun" is locatedbetween the

anterior scalene

m. and the middlescalene m.; it

arches posteriorly

over the cervicalparietal pleura

deep cervical costocervical

trun"

unnamed muscular

branches

deep muscles of

the posteriornec"

deep cervical a.

anastomoses withthe occipital a.

near the occipital

bone

dorsalscapular subclavian a.,!rd part unnamed muscularbranches levator scapulaem.,rhomboideus

ma'or m.,

rhomboideusminor m.

dorsal scapular a.anastomoses withthe suprascapular

a. and the

subscapular a. toform the scapular

anastomosis;

dorsal scapular a

is a branch of thetransverse

cervical a. in

$!%& of casesgreat anterior

radicular

the spinal br. of

the lower

posteriorintercostal a.,

subcostal a., or

upper lumbar a.,

no named branches lower spinal

cord

great anterior

radicular a.

anastomoses withthe anterior spinal

a. at lower

thoracic or upper


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usually on left lumbar spinalcord levels

intercostal,posterior

highestintercostal

(upper intercostal

spaces),descending

thoracic aorta

(!rd11thintercostal

spaces)

posterior br., spinalbr., anterior br.,

collateral br.,lateral cutaneous

br.

intercostalmuscles, spinal

cord andvertebral

column, deepbac" muscles,

s"in and

superficialfascia overlying

the intercostal

spaces

posteriorintercostal aa.

supply the lateraland posterior

portions of theintercostal space;

anterior

intercostal aa.supply the

anterior portions

of the intercostalspaces

lateral sacral internal iliac a.,posterior

division

spinal brs. sacrum, sacralnerve rootlets,

meninges,

ad'acentmuscles

there are usually lateral sacral aa.

on each side, a

superior one andan inferior one

lumbar abdominal aorta anterior br.,

posterior br., spinalbr.

psoas ma'or m.,

psoas minor m.,uadratus

lumborum m.,

spinal cord andvertebral

column, deepbac" muscles

the * lumbar

arteries on eachside arise from

the posterior

surface of theaorta at the level

of vertebrae +1+*; they course

posterior to thepsoas ma'or m.

median sacral abdominal aorta th lumbar aa. sacrum median sacral a.

appears to be the

continuation of

the abdominalaorta in the

median plane,

although it ismuch smaller in

si#e

posteriorradicular

they arise asmultiple

branches of

several vessels

no named branches meninges;spinal cord;

spinal nerve;

dorsal rootlets

posteriorradicular aa.

accompany the

dorsal rootlets;


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(vertebral,posterior

intercostal,

lumbar, andlateral sacral

aa.)

they anastomosewith the posterior

spinal aa.

posteriorspinal

contributionsreceived from

several arteries

(posteriorinferior

cerebellar,

vertebral,posterior

intercostal,

subcostal,lumbar, lateralsacral aa.)

pial arterial plexus spinal cord,especially the

dorsal columns;

medulla(nucleus

cuneatus and

nucleus gracilis)

paired; posteriorspinal aa.

anastomose with

the posteriorradicular brs. of

the spinal rami of


intercostal,

subcostal, lumbarand lateral sacralaa.

radicular,

anterior

they arise as

multiple

branches of

several vessels(vertebral,

posterior

intercostal,lumbar, and

lateral sacral

aa.)

they accompany

the ventral rootlets

to reach the spinal

cord

meninges;

spinal cord;

spinal nerve;

ventral rootlets

anterior radicular

aa. anastomose

with the anterior

spinal a.

radicular,

great anterior

the spinal br. of

the lower

posteriorintercostal a.,

subcostal a., or

upper lumbar a.,usually on left

no named branches lower spinal

cord

great anterior

radicular a.

anastomoses withthe anterior spinal

a. at lower

thoracic or upperlumbar spinal

cord levels

radicular,

posterior

they arise as

multiple

branches ofseveral vessels

(vertebral,

posterior

intercostal,

no named branches meninges;

spinal cord;

spinal nerve;dorsal rootlets

posterior

radicular aa.

accompany thedorsal rootlets;

they anastomose

with the posterior

spinal aa.


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lumbar, andlateral sacral

aa.)

sacral, lateral internal iliac a.,

posteriordivision

spinal brs. sacrum, sacral

nerve rootlets,meninges,

ad'acentmuscles

there are usually

lateral sacral aa.on each side, a

superior one andan inferior one

sacral, median abdominal aorta th lumbar aa. sacrum median sacral a.appears to be the

continuation of

the abdominalaorta in the

median plane,

although it ismuch smaller in

si#e

scapular,circumflex

subscapular a. unnamed muscularbranches

teres ma'or m.,teres minor m.,

infraspinatus m.

circumflexscapular a.

anastomoses with

the suprascapulara. and the dorsal

scapular a. to

form the scapularanastomosis

scapular,dorsal

subclavian a.,!rd part


levator scapulaem.,

rhomboideus

ma'or m.,rhomboideus

minor m.

dorsal scapular a.anastomoses with

the suprascapular

a. and thesubscapular a. to

form the scapular

anastomosis;

dorsal scapular ais a branch of the

transverse

cervical a. in$!%& of cases

spinal,

anterior

contributions

received fromseveral arteries

(vertebral,

posterior

pial arterial plexus meninges;

spinal cord;medulla (dorsal

motor nucleus

of cranial nerve

the anterior spinal

a. anastomoseswith the anterior

radicular brs. of

the spinal rami of


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intercostal,subcostal,

lumbar, lateral

sacral aa.)

X, nucleusambiguus,

spinal accessory


nucleus)


intercostal,

subcostal, lumbarand lateral sacral

aa.

spinal,posterior

contributionsreceived from

several arteries

(posteriorinferior

cerebellar,

vertebral,posterior

intercostal,

subcostal,lumbar, lateralsacral aa.)

pial arterial plexus spinal cord,especially the

dorsal columns;

medulla(nucleus

cuneatus and

nucleus gracilis)

paired; posteriorspinal aa.

anastomose with

the posteriorradicular brs. of

the spinal rami of


intercostal,

subcostal, lumbarand lateral sacralaa.

thoracodorsal subscapular a. unnamed muscular

branches

latissimus dorsi

m.

thoracodorsal a.

accompanies the

thoracodorsal n.

transverse

cervical

thyrocervical

trun"

unnamed muscular

branches, possibly

the dorsal scapulara.

trape#ius muscle

and surrounding

tissues

transverse

cervical a. gives

rise to the dorsalscapular a. $!%&

of the time

trun",

costocervical

subclavian a.,

nd part

deep cervical a.,

highest intercostal

a.

deep muscles of

the posterior

nec"; posteriorends of the first

intercostal

spaces

costocervical

trun" is located

between theanterior scalene

m. and the middle

scalene m.; it

arches posteriorlyover the cervical

parietal pleura

trun",thyrocervical

subclavian a.,1st part

inferior thyroid a.,transverse cervical

a., suprascapular a.

lower nec",posterior

shoulder,

thyroid gland

thyrocervicaltrun" does not

give rise to the

ascendingcervical a. it is a

branch of the

inferior thyroid a.


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vertebral subclavian a.(1st part)

spinal brs.,muscular brs.,

anterior spinal a.,

posterior inferiorcerebellar a.,

medullary brs.,meningeal brs.,basilar a.

deep nec",cervical spinal

cord, spinal

cord; medulla(dorsal motor

nucleus ofcranial nerve X,nucleus

ambiguus,

spinal accessory


nucleus)

vertebral a.anastomoses with

the internal

carotid a. in thecerebral arterial

circle (of -illis);it courses throughthe transverse

foramina of

vertebrae 1/

Bones of the Back Region - Listed in Superior to Inferior

Order

Bone Structure Description Notes

occipital

the bone forming the

posterior surface of

the s"ull

it articulates superolaterally with

the parietal bones through the

lambdoid suture, anteroinferiorlywith the temporal bone and

anteriorly with the body of the

sphenoid bone

external

occipital

protuberance

a low process on the

external surface of the

occipital bone in the

it is an attachment site for the

ligamentum nuchae; the superior

nuchal lines of the two sides meet


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midline in the midline at the externaloccipital protuberance; also "nown

as: inion

inferior nuchal

line

a low ridge that runs

transversely on theexternal surface of the

suamous part of theoccipital bone inferior

to the superior nuchal

line

it is an attachment site for deep

nec" muscles

superior nuchal

line

a low ridge that runs

transversely on theexternal surface of the

suamous part of the

occipital bone

it is an attachment site the for the

trape#ius and splenius mm.

occipital

condyle

a low, wide pro'ection

from the inferior

surface of the lateralpart of the occipital

bone

paired; it articulates with the atlas

vertebra one of a series of

irregular bones that

form the spine

a vertebra has two parts: the

vertebral body and the vertebral

arch; there are !! vertebrae total: 0cervical, 1 thoracic, lumbar,

fused to form the sacrum, *coccygeal; features of a typicalvertebra include: body, pedicles,

transverse processes, laminae,

articular processes, spinous process

vertebral body the largest part of the

vertebra

it is shaped li"e a short cylinder;

ad'acent vertebral bodies articulate

through a symphysis

vertebral arch the ring of bone

formed by the paired

pedicles and pairedlaminae of the

vertebra

the transverse processes and

spinous process are attached to the

neural arch; the neural arch protectsthe spinal cord

pedicle short strong process

that extends

posteriorly from theposterolateral surface

paired; it connects the body with

the transverse process; it is mar"ed

by superior inferior vertebralnotches;


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of the vertebral body

transverse

process

a lateral process the

extends from the'unction of the pedicle

and the lamina of thevertebra

a site for muscle attachment and rib

articulation

lamina a broad flat plats of

bone located between

the transverse processand the spinous

process of the vertebra

paired; it is flattened mar"edly in

the anteroposterior direction;

ligamenta flava span the intervalbetween the laminae of ad'acent

vertebrae

articular

processes

processed that pro'ect

inferiorly and

superiorly from the

'unction of the laminaand pedicle of the

vertebra

two pair on each vertebra (superior

and inferior); the superior articular

processes of one vertebra articulate

with the inferior processes of thead'acent vertebra through synovial

'oints

intervertebral

notch

a notch on the

superior and inferiorsurface of the

vertebral pedicle

the superior intervertebral notch of

one vertebra combined with theinferior intervertebral notch of the

ad'acent vertebra forms the

intervertebral foramen

intervertebral

foramen

an opening between

the pedicles of

ad'acent vertebrae

ad'acent intervertebral notches form

the intervertebral foramen; an

opening for passage of the spinalnerve

vertebral canal the opening formed bythe combination of the

body and the vertebral

arch

it contains the spinal cord,meninges, epidural fat and the

internal vertebral plexus of veins

spinous process a posterior midline

process arising from

the 'unction of the two

laminae of thevertebra

it pro'ects downward and inferiorly;

it is an important site of muscle

attachment; spinous processes of

cervical vertebra / are bifid

cervical

vertebrae

the seven vertebrae of

the nec"

cervical vertebrae have the features

of the typical vertebra plus all have

transverse foramina (for passage ofthe vertebral artery); / have

bifid spinous processes; cervical


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vertebrae have relatively smallbodies; several cervical vertebra are

named: atlas, axis, vertebra

prominens

atlas (1) the first cervicalvertebra it is called atlas in comparison the

mythological 2ree" 3itan 4tlas,

who bore the weight of the worldon his shoulders; it has no vertebral

body, only anterior posterior

arches; it articulates with the

odontoid process of the axis

axis () the second cervicalvertebra

the odontoid process (dens) pro'ectssuperiorly from its body; it

articulates with the anterior arch of

the atlas

vertebraprominens

the seventh cervicalvertebra

it has a long, nonbifid spinousprocess which is prominent at the

nape of the nec", hence its name

thoracic

vertebrae

the 1 vertebrae

associated with the

thoracic region

thoracic vertebrae have the features

of a typical vertebra plus they are

characteri#ed by long slender spinesthat pro'ect inferiorly; they have

facets for articulation with ribs;thoracic vertebrae have bodies ofintermediate si#e

costal articular

facet on thebody

small smooth areas at

the 'unction of thebody and the vertebral

arch

most thoracic vertebrae have

costal facets on each side (onesuperior and one inferior); the

superior costal facet of one vertebra

and the inferior costal facet of thead'acent vertebra both articulate

with the head of the same rib; also

"nown as demifacets

costal articular

facet on thetransverse

process

a small smooth area

on the transverseprocess of the thoracic

vertebra

it articulates with the articular facet

on the tubercle of the rib

lubar the vertebrae located lumbar vertebrae have the features


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vertebrae in the lumbar region of a typical vertebra plus they arecharacteri#ed by short, blunt spines

that pro'ect posteriorly; lumbar

spines do not overlap ma"ing thelumbar level a good one for spinal

tap; lumbar vertebrae are builtstrong and have the largest bodiesof all vertebrae

sacru a triangular bone that

is the posteriors"eletal element

forming the pelvis

it is formed by fused vertebrae;

the sacrum and two os coxae bonesform the pelvis

anterior sacral

foramina

an opening in the

anterior surface of the

sacrum

there are four pairs; each transmits

the ventral primary ramus of the

respective sacral spinal nerve;branches of the lateral sacral aa.

enter the sacral canal through these

openings

posterior sacral

foramina

an opening in the

posterior surface of

the sacrum

there are four pairs; each transmits

the dorsal primary ramus of the

respective sacral spinal nerve

promontory a pro'ection of the

superior part of thesacrum in an anterior

direction

the body of the fifth lumbar

vertebra sits on the sacralpromontory and articulates with it

through a symphysis

sacral canal the opening in the

center of the sacrum

it is the continuation of the

vertebral canal at sacral vertebral

levels

articular surface the roughened area

located on the lateralsurface of the sacrum

this surface articulates with the

ilium in the sacroiliac articulation

body the central portion of

the sacrum

the body is euivalent to the bodies

of the other vertebra

base the superior surface ofthe sacrum

the base of the sacrum articulateswith the fifth lumbar vertebrathrough an intervertebral dis"

sacral hiatus an opening in theposterior surface of

the sacrum in the

midline

it is a normal feature that resultsfrom the failure of fusion of the

laminae of the fifth sacral segment

(and sometimes the fourth) during


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development

ala the lateral portion of

the sacrum

paired; it pro'ects laterally from the

body of the sacrum; it representsthe fused costal and transverse

processes of the first sacral vertebra

coccy! the most inferior

portion of the

vertebral column

the coccyx results from the fusion

of the four coccygeal vertebrae; it

may be a single bone or the first

coccygeal vertebra may beseparated from the other three; it

articulates with the fifth sacral

segment; coccygeal vertebrae arereduced in complexity, having no

pedicles, laminae or spines

"asciae of the Back Region - Arranged Alphabetically

Structure Location#Description Notes

fascia,

infraspinatus

deep fascia covering the

superficial surface of theinfraspinatus m.

infraspinatus fascia attaches to the spine

of the scapula and the posterior surface ofthe scapula at the margins of the

infraspinatus fossa; it is a strong origin

for the infraspinatus m.

fascia, nuchal deep fascia covering the

muscles of the posterior nec"

nuchal fascia is part of the prevertebral

layer of deep cervical fascia

fascia,

thoracolumbar

deep fascia surrounding the

erector spinae muscle mass

thoracolumbar fascia in lumbar regions

serves as an origin for the latissimusdorsi m.


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$oints and Ligaents of the Back Region - Listed

Alphabetically

$oint or

ligaentDescription Notes

anteriorlongitudinal

ligament

a ligament that courses fromsuperior to inferior along the

anterior surfaces of allvertebral bodies

it lies directly posterior to the thoracicand abdominal viscera

interspinous

ligament

a ligament that connects the

spinous processes of two

ad'acent vertebra

a syndesmosis

intervertebral a fibrocartilaginous dis" a symphysis; it is composed of two


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disc between ad'acent vertebralbodies

parts: an outer anulus fibrosus and aninner nucleus pulposus; the nucleus

pulposus is the remnant of the

notochord; the intervertebral dis"s areimportant shoc" absorbers between

vertebrae

ligamenta flava a ligament formedpredominantly by elastic fibers

which 'oins the laminae of

ad'acent vertebrae

a syndesmosis; paired; the ligamentumflavum is penetrated by the needle

during spinal tap; the word flavum is

derived from the +atin word flavus,which means 5yellow5 a reference to

the predominance of yellow elastic

fibers which gives this ligament itsgrossly visible color

nuchal ligament a midline ligament that extendsposteriorly from the spinous

processes of cervical vertebrae

and extends from the base ofthe s"ull to the 0th cervical

vertebra

a syndesmosis; it provides muscleattachments to the cervical spinous

processes without the necessity of long

spinous processes that would hinderextension of the nec"

posteriorlongitudinal

ligament

a ligament that courses fromsuperior to inferior along the

posterior surfaces of all

vertebral bodies

it is broader at the intervertebral dis"sand narrow at the vertebral bodies

which gives it a scalloped edge; it is

located in the vertebral canal; it is 673penetrated by the needle during spinal

tap

supraspinous

ligament

a ligament that connects the

tips of the spinous processes of

thoracic and lumbar vertebrae

a syndesmosis; the supraspinous

ligament begins at the 0 vertebra and

ends at the midsacral segmental level;it serves as a muscle attachment site

#ygapophyseal

'oint

a small 'oint between the

articular processes of ad'acentvertebrae

a synovial plane 'oint


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Note: Although the back and extremities contain numerous lymphaticcapillaries, within these regions there are very few lymph nodesthat are large enough to be named.

Lyphatics of the Back - Listed Alphabetically

Structure LocationAfferents

fro

%fferents

to

Regions

drainedNotes

occipitalnodes

superiornuchal line,

along the

course of

lymphaticvessels from

the posterior

head and

accessorynodes

occipitalpart of the

scalp and

the

occipital nodes are or !nodes located between

the attachments of the

sternocleidomastoid m.


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the occipitala. and v.

nec" superiornec"

and the trape#ius m.

&uscles of the 'pper Lib that are dissected in the

Back Region

&uscle Origin Insertion Action Innervation Artery Notes

latissimusdorsi

vertebralspines from

30 to the

sacrum,posterior

third of the

iliac crest,

floor of theintertubercul

ar groove

extendsthe arm

and

rotatesthe arm

medially

thoracodorsal nerve

(0,8) from

the posteriorcord of the

brachial

plexus

thoracodorsal a.

theinserting

tendon

twists sothat fibers

originating

highest


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lower ! or* ribs,

sometimes

from theinferior

angle of thescapula

insertlowest

levator

scapulae

transverse

processes

of 1*vertebrae

medial

border of

the scapulafrom the

superior

angle to thespine

elevates

the

scapula

dorsal

scapular

nerve ();the upper

part of the

musclereceives

branches of

! *

dorsal

scapular a.

levator

scapulae is

named forits action

rhomboide

us ma'or

spines of

vertebrae33

medial

border ofthe scapula

inferior to

the spine of

the scapula

retracts,

elevatesand

rotates

the

scapulainferiorly

dorsal

scapularnerve ()

dorsal

scapular a.

named for

its shape

rhomboideus minor

inferior endof the

ligamentumnuchae,

spines ofvertebrae

0 and 31

medialborder of

the scapulaat the root of

the spine ofthe scapula

retracts,elevates

androtates

thescapula

inferiorly

dorsalscapular

nerve ()

dorsalscapular a

named forits shape

serratus

anterior

ribs 18 or

9

medial

border of

the scapulaon its costal

(deep)

surface

it draws

the

scapulaforward;

the

inferiorfibers

rotate the

scapulasuperiorl

y

long thoracic

nerve (from

ventral rami0)

lateral

thoracic a.

a lesion of

long

thoracicnerve will

cause

winging ofthe scapula

(i.e., the

medialborder of

the scapula

falls away

from the


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posteriorchest wall

and loo"s

li"e anangels

wing)

trape#ius medialthird of the

superior

nuchal line,external

occipital

protuberance,

ligamentum

nuchae,spinousprocesses

of

vertebrae031

lateral thirdof the

clavicle,

medial sideof the

acromion

and theupper crest

of the

scapularspine,tubercle of

the scapular

spine

elevatesand

depresses

thescapula

(dependi

ng onwhich

part of

themusclecontracts)

; rotates

thescapula

superiorl

y; retractsscapula

motor: spinalaccessory

(X),

proprioception: !*

transversecervical a.

named forits shape;

trape#ius is

an exampleof a muscle

that

migratesduring

developme

nt from itslevel oforigin

(cervical)

to its finalposition,

pulling its

nerve andartery

along

behind

&uscles of the Back Region - Listed Alphabetically

&uscle OriginInsertio

nAction

Innervatio

nArtery Notes

erector spinae iliac crest,

sacrum,

transverseand spinous

processes of

vertebraeand

supraspinal

ligament

angles of

the ribs,

transverse and

spinous

processes of

vertebrae

,posterior

extends

and

laterallybends

the

trun",nec"

and

head

segmentall

y

innervatedby dorsal

primary

rami ofspinal

nerves 1


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aspect ofthe s"ull

position andspinalis

medially; each

of thesecolumns has

multiplenamed parts

iliocostalis iliac crest

and sacrum

angles of

the ribs

extends

and

laterallybends

the

trun"and

nec"

dorsal

primary

rami ofspinal

nerves *


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andmastoid

process

nec"and

head

aa.,subcostal

aa.,

lumbar aa.

into thoracis,cervicis and

capitis

portions

multifidus sacrum,transverse

processes of!+

spinousprocesse

s *vertebral

levels

superiorto their

origin

extendand

laterallybend

trun"

andnec",

rotate to

opposite side

dorsalprimary

rami ofspinal

nerves 1

+

suppliedsegmentall

y by: deepcervical a.,

posterior

intercostalaa.,

subcostal

aa.,lumbar aa.

semispinalis,multifidus and

rotatores ma"eup the

transversospin

al musclegroup

obliuuscapitis inferior

spinousprocess of

the axis

transverse process

of atlas

rotatesthe

head to

thesame

side

suboccipital nerve

(=>? of

1)

occipital a. greateroccipital nerve

(=>? of )

passessuperiorly

around the

inferior

margin ofinferior

obliue

obliuus

capitis superior

transverse

process ofatlas

occipital

boneabove

inferiornuchal

line

extends

thehead,

rotatesthe

head to

thesame

side

suboccipita

l nerve(=>? of

1)

occipital a. the

suboccipitaltriangle is

formed byobliuus

capitis

superior andinferior and

rectus capitis

posteriorma'or

rectus capitisposterior ma'or spinousprocess of

axis

inferiornuchal

line

extendsthe

head,

rotate tosame

side

suboccipital nerve

(=>? of

1)

occipital a. none

rectus capitis posterior inferior extends suboccipita occipital a. rectus capitis


21/31

posteriorminor

tubercle ofatlas

nuchalline

medially

thehead

l nerve(=>? of

1)

posteriorminor is

deeper and

inserts moremedial than

rectus capitisposteriorma'or

rotatores transverse

processes

long

rotatores: spines

vertebraeabove

origin;

shortrotatores: spines

1

vertebraeabove

origin

rotates

thevertebra

l

columnto the

opposit

e side

dorsal

primaryrami of

spinal

nerves 1+

supplied

segmentally by: deep

cervical a.,

posteriorintercostal

aa.,

subcostalaa.,lumbar aa.

semispinalis,

multifidus androtatores ma"e

up the

transversospinal muscle

group

semispinalis transverse

processes of

031

capitis:

bac" of

s"ullbetween

nuchal

lines;cervicis

thoracis:

spines */

vertebrae

aboveorigin

extends

the

trun"and

laterally

bendsthe

trun",

rotates

thetrun" to

the

opposite side

dorsal

primary

rami ofspinal

nerves 1

31

supplied

segmentall

y by: deepcervical a.,

posterior

intercostalaa.,

subcostal

aa.,

lumbar aa.

three parts are

named based

on theirinsertions:

capitis,

cervicis andthoracis;

semispinalis,

multifidus and

rotatores ma"eup the

transversospin

al musclegroup

serratusposterior

inferior

thoracolumbar fascia,

spines of

vertebrae

31131 and+1+

ribs 91,

lateral to

the

angles

pullsdown

lower

ribs

branchesof the

ventral

primary

rami ofspinal

nerves 39

31

lowestposterior

intercostal

a.,

subcostala., first

two

lumbar aa.

a respiratorymuscle, it

receives

ventral ramus

innervation;embryonically

related to the

intercostal


22/31

muscles, notthe deep bac"

mm.

serratus

posteriorsuperior

ligamentum

nuchae,spines of

vertebrae 0and 313!

ribs 1*,

lateral tothe

angles

elevates

theupper

ribs

branches

of theventral

primaryrami of

spinal

nerves 313*

posterior

intercostalaa. 1*

a respiratory

muscle, itreceives

ventral ramusinnervation;

embryonically

related to theintercostal

muscles, not

the deep bac"mm.

spinalis spinousprocesses at

inferior

vertebrallevels

spinousprocesse

s at

superiorvertebral

levels

and base

of thes"ull

extendsand

laterally

bendstrun"

and

nec"

dorsalprimary

rami of

spinalnerves

+!

suppliedsegmentall

y by: deep

cervical a.,posterior

intercostal

aa.,

subcostalaa.,

lumbar aa.

most medialpart of the

erector spinae;

may besubdivided

into thoracis,

cervicis and

capitisportions

splenius ligamentum

nuchae andspines 0

3/

capitis:

mastoidprocess

superior

nuchal

linelaterally;

cervicis:

posteriortubercles

of 1

!vertebrae

extends

andlaterally

bendsnec"

and

head;rotates

head to

sameside

dorsal

primaryrami of

spinalnerves

/

supplied


cervical a.,posterior

intercostal

aa.

splenius

meansbandage; it

gets its namefrom its broad,

flat shape

splenius capitis ligamentumnuchae and

spines of

03/

vertebrae

mastoidprocess

and

lateral

end of

extendsand

laterally

bends

the

dorsalprimary

rami of

spinal

nerves

suppliedsegmentall

y by: deep

cervical a.,

posterior

named for itsshape:

splenius

means

bandage and


23/31

thesuperior

nuchal

line

nec"and

head,

rotateshead to

thesameside

/ intercostalaa.

capitis refersto the

insertion of

this portion ofthe muscle

splenius

cervicis

ligamentum

nuchae andspines of

03/

vertebrae

posterior

tuberclesof the

transvers

eprocesse

s of 1

!vertebrae

extends

andlaterally

bends

nec"and

head,

rotateshead tothe

same

side

dorsal

primaryrami of

spinal

nerves /

supplied


cervical a.,

posteriorintercostal

aa.

named for its

shape:splenius

means

bandage andcervicis refers

to the

insertion ofthis portion ofthe muscle


24/31

Nerves of the Back Region - Listed Alphabetically

Nerve Source Branches &otor Sensory Notes

accessory cranialroot:

medulla nucleus

ambiguus

; spinal

root:spinal

nucleus

of theupper

cervicalspinalcord

no namedbranches

2


25/31

nerves


26/31

nerve; location ofthe cell bodies of

somatic afferent

(sensory) neurons

dorsalscapular

n.

brachialplexus

(br. of ventral

primary

ramus)

no namedbranches

rhomboideusma'or and minor

mm.; levatorscapulae m.

none dorsal scapular n.passes through the

scalenus mediusm.

intercosta

l n.

ventral

primaryrami of

spinal

nerves31311

lateral

anteriorcutaneous

brs.

intercostal

muscles;abdominal wall

muscles (via 30

311); muscles ofthe forearm and

hand (via 31)

s"in of the

chest andabdomen

anterolaterall

y; s"in of themedial side of

the upper

limb (via 313)

intercostal

n.travels below theposterior

intercostal a. in

the costal groove

occipital,

greater

dorsal

primaryramus of

spinal

nerve (medial

br.)

no named

branches

posterior nec"

muscles

s"in of the

posteriorsurface of the

scalp

muscles

innervated by thisnerve develop

from epimeres in

the embryo

occipital,

lesser

ventral

primary

ramus ofspinal

nerve

no named

branches

none s"in behind

the ear

lesser occipital n.

arises from the

cervical plexus

occipitalis tertius

dorsalprimary

ramus of

spinal

nerve !(medial

br.)

no namedbranches

posterior nec"muscles

s"in of theposterior

surface of the

nec"

musclesinnervated by this

nerve develop

from epimeres in

the embryo

ramus,

dorsalprimary

first

branchoff of the

dorsal

numerous to the deep bac"

mm.; sympatheticinnervation to the

s"in

general sense

(touch,pressure,

pain, heat,

a mixed nerve

containing bothmotor and sensory

fibers


27/31

side ofthe spinal

nerve

cold, etc.) tothe s"in of

the bac"

ramus,

ventralprimary

first

branchoff of the

ventralside of

the spinal

nerve

numerous to s"eletal mm. of

the nec", trun"and extremities;

sympatheticinnervation to the

s"in

general sense

(touch,pressure,

pain, heat,cold, etc.) to

the s"in of

the trun"(except the

bac") and

extremities;visceral pain

via the white

rami of thesympatheticnervous

system (31

+)

a mixed nerve


fibers

root,

dorsal

from the

dorsalhorn of

the spinal

cord tothe spinal

nerve

none none general sense

(touch,pressure,

pain, heat,

cold, etc.)

dorsal root is

entirely sensory infunction; it is

located dorsal to

the denticulateligament

root,ventral

from theventral

horn of

the spinalcord to

the spinal

nerve

none to s"eletal mm.;preganglionic

sympathetic (31

+)

none entirely motor infunction; located

ventral to the

denticulateligament; at all

spinal core levels

it contains 2


28/31

spinal n. formed atthe point

where the

dorsaland

ventralrootletsmeet; it

ends

where the

dorsaland

ventral

primaryrami

diverge

dorsalprimary

ramus;

ventralprimary

ramus

to s"eletal mm.;some levels carry

preganglionic

sympathetic axons(31+)

general sense(touch,

pressure,

pain, heat,cold, etc.)

from theentire surfaceof the nec",

trun" and

extremities;

visceral pain(via the white

ramus

communicansand the

sympathetic

nervoussystem)

located at theintervertebral

foramen; there are

!1 pairs of spinalnerves 8

cervical, 1thoracic, lumbar, sacral, 1

coccygeal

ventral

primaryramus

first

branchoff of the

ventral

side ofthe spinal

nerve

numerous to s"eletal mm. of

the nec", trun"and extremities;

sympathetic

innervation to thes"in

general sense

(touch,pressure,

pain, heat,

cold, etc.) tothe s"in of

the trun"

(except the

bac") andextremities;

visceral pain

via the whiterami of the

sympathetic

nervoussystem (31

+)

a mixed nerve


fibers

ventral

root

from the

ventral

horn ofthe spinal

cord to

the spinalnerve

none to s"eletal mm.;

preganglionic

sympathetic (31+)

none entirely motor in

function; located

ventral to thedenticulate

ligament; at all

spinal core levelsit contains 2


29/31

contains 2A@(preganglionic

sympathetic) for

blood vessels,sweat glands,

thoracic viscera,abdominal viscera,pelvic viscera

(opographical Anatoy of the Back - Listed

Alphabetically

Structure#Space Description#Boundaries Significance

external occipital a bump located in the midline on the the medial ends of the


30/31

protuberance posterior surface of the occipital bone superior nuchal lines meetat the external occipital

protuberance; the

ligamentum nuchaeattaches here

lumbar triangle a triangle defined by the border of the

latissimus dorsi m. medially, the externalabdominal obliue m. laterally and the

iliac crest inferiorly; its floor is the

internal abdominal obliue m.

lumbar triangle may be

the site of an abdominalhernia; also "nown as:

triangle of >etit

natal cleft midline cleft between the buttoc"s natal cleft lies between the

gluteus maximus muscles

paravertebral line an imaginary line located lateral to the

midline on the posterior surface of the

body, parallel to the vertebral column

paravertebral line is used

as a descriptive landmar"

uadrangularspace

an area on the posterior surface of thebac" bounded by the teres minor m.

superiorly, the teres ma'or m. inferiorly,

the long head of the triceps brachii m.medially and the humerus laterally

the axillary n. and theposterior circumflex

humeral a. pass through

this space

triangle of

auscultation

a triangle located below the inferior angle

of the scapula bounded by the trape#iusm. medially, rhomboideus ma'or m.

superiorly and the latissimus dorsi m.

inferiorly; its floor is the posteriorthoracic wall

triangle of auscultation is

used to listen to(auscultate) the lungs

because the stethoscope

can be placed close to thethoracic wall at this

location

triangular interval the interval between the teres ma'or m.

superiorly, long head of the triceps brachii

m. medially and humerus laterally

the radial n. passes

through this interval to get

from the axilla to theposterior surface of the

humerus

triangular space the space bounded by the teres minor m.

superiorly, the teres ma'or m. inferiorlyand the long head of the triceps brachii m.

laterally

the circumflex scapular

vessels are located in thisspace as they pass from

the axilla to the dorsum ofthe scapula

vertebraprominens

the 0 vertebra, so named because itsspine is easily seen and palpated

vertebra prominens is aneasily palpable landmar"

which indicates the level


31/31

of transition from cervicalto thoracic vertebra

vertebral furrow midline furrow down the bac" surface landmar" thatindicates the location of

the vertebral spines; theerector spinae muscle

masses lie on either sideof it

Documents

Anatomy of Back Region