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Anatomy Tables - Superficial Back

Topographical Anatomy of the Back

Structure/Space Description/Boundaries Significance

external occipital

protuberance

(N4, TG7-05)

a projection on the external

surface of the squamous part of

the occipital bone in the midline

it is the attachment site of the

ligamentum nuchae and the

trapezius m.; its highest point

is called the inion (Latin,

occiput = against head; Greek,

inion = back of head)

vertebra (spina)prominens

(N21, TG1-01)

the seventh cervical vertebra it has a long, non-bifidspinous process which is

prominent at the nape of theneck, hence its name (Latin,

vert = to turn)

Viscera/Fascia

Organ/Part of

OrganLocation/Description

skin the membranous covering of the body, also known as the cutis

epidermis

the outer epithelial portion of the skin including these layers (from

superficial to deep): stratum corneum (or horny layer), stratum

lucidum (or clear layer), stratum granulosum (or granular layer),stratum spinosum (or spiney layer), stratum germintivum (or

germinative layer), stratum basale (or basal layer) (Greek, epi = on+ derma = skin)

dermis

blood, lymph vessels, nerves, sebaceous glands, and sweat glands

occur in this layer of the skin, which lies between the epidermis

and fatty (subcutaneous) layer

subcutaneous

tissue

also known as the superficial fascia, this layer lies deep to the skin

and consists of loose connective tissue containing fat, cutaneous

nerves, superficial veins, lymph vessles and nodes (Latin, sub =

beneath + cutis = skin)

investing (deep)fascia

a dense layer of connective tissue between the subcutaneous tissueand the muscles; surrounds the entire muscle group

muscular fascia a dense layer of connective tissue surrounding individual muscles


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neurovascular

bundle

a term that describes the typical common path of a vein, artery,

and nerve

thoracolumbar

aponeurosis(fascia)

extends laterally from the spinous processes and forms a thin

covering for the deep muscles in the thoracic region and a strong,thick covering for muscles in the lumbar region.

Bones of the Back Region

Bone Structure Description Notes

occipital

(N4, TG7-05)

the bone forming

the posterior

surface of the

skull

it articulates superolaterally with

the parietal bones through the

lambdoid suture, anteroinferiorly

with the temporal bone and

anteriorly with the body of the

sphenoid bone (Latin, occiput =

against head)

external

occipitalprotuberance

(N4, TG7-05)

a low process on

the externalsurface of the

occipital bone inthe midline

it is an attachment site for the

ligamentum nuchae; the superiornuchal lines of the two sides

meet in the midline at theexternal occipital protuberance;

also known as: inion (Latin,occiput = against head; Greek,

inion = back of head)

mastoid

process

(N4,N8,N13,

TG7-05, TG7-06)

the process

located

posteroinferior to

the externalacoustic meatus

it projects inferiorly from the

junction of the petrous and

squamous parts of the temporal

bone; it contains the mastoid aircells that open into tympanic

cavity through the mastoidantrum (Latin/Greek, mastoides

= resembling a nipple)

superior

nuchal line

(N174, TG7-

06)

a low ridge that

runs transversely

on the external

surface of the

squamous part ofthe occipital bone

it is an attachment site for

trapezius and splenius mm.

(Latin, nucha = nape)

vertebra one of a series of

irregular bonesthat form the

spine

a vertebra has two parts: the

vertebral body and the vertebralarch; there are 33 vertebrae total:

7 cervical, 12 thoracic, 5 lumbar,

5 fused to form the sacrum, 4

coccygeal; features of a typical


3/9

vertebra include: body, pedicles,

transverse processes, laminae,

articular processes, spinousprocess

spinous

process(N21, TG1-

03D, TG1-

03E, TG1-

05B, TG1-

05E)

a posterior

midline processarising from the

junction of the

two laminae of the

vertebra

it projects downward and

inferiorly; it is an important siteof muscle attachment; spinous

processes of cervical vertebra 2-

6 are bifid

vertebra

prominens(N21, TG1-

01)

the seventh

cervical vertebra

it has a long, non-bifid spinous

process which is prominent atthe nape of the neck, hence its

name

sacrum(N157, TG1-

08)

a triangular bonethat is the

posterior skeletal

element forming

the pelvis

it is formed by 5 fused vertebrae;the sacrum and two os coxae

bones form the pelvis. (Latin,

"os sacrum" meant "Holy Bone".

"Holey" bone could remind you

of the sacral foramina.)

posterior

sacralforamina

an opening in the

posterior surfaceof the sacrum

there are four pairs; each

transmits the dorsal primaryramus of the respective sacral

spinal nerve (Latin, foramen =an aperture)

coccyx(N157, TG6-

04)

the most inferiorportion of the

vertebral column

the coccyx results from thefusion of the four coccygeal

vertebrae; it may be a single

bone or the first coccygeal

vertebra may be separated from

the other three; it articulates with

the fifth sacral segment;

coccygeal vertebrae are reduced

in complexity, having no

pedicles, laminae or spines.

(Latin/Greek, coccyx = cuckoo's

beak)

pectoralgirdle

(N420,N421,

TG2-03A)

formed by the scapulae and clavicles and joined to the manubrium, itconnects the upper limbs to the axial skeleton

clavicle(TG2-03A)

an "S" shaped

bone located

between the

it articulates medially with the

manubrium of the sternum and

laterally with the acromion


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sternum and the

scapula

process of the scapula; it forms a

strut that supports the upper

limb; it is frequently fractured; itis the first bone to begin

ossification during development(Latin, clavicula = little key, this

term was used to refer to thecatch that fastens a window as

well as to keys. Curved windowfasteners resemble the shape of

this bone)

scapula(TG2-03A,

TG2-03B)

the bone of the

shoulder

the scapula floats in a sea of

muscles, so it is difficult to

fracture; it articulates with the

axial skeleton through only one

bone - the clavicle at the

coracoclavicular and

acromioclavicular joints

medial border the border of thescapula that runs

from the superior

angle to the

inferior angle

it is an important site of muscleattachments for the intermediate

layer of back muscles, including

rhomboid major and minor and

serratus anterior

superior angle the angle of the

scapula formed at

the union of the

superior and

medial borders

it is the attachment site for the

levator scapulae m.

inferior angle the angle of thescapula formed by

the union of the

medial and lateral

borders

the inferior angle of the scapulaoften has a slip of origin of the

latissimus dorsi attached to it

spine a heavy ridge that

runs from the

medial border of

the scapula to the

acromion process

it supports the acromion process;

it divides the posterior surface of

the scapula into a supraspinatous

fossa and an infraspinatous fossa

acromion a broad, flatprocess located at

the lateral end of

the scapular spine

it articulates with the claviclethrough a synovial joint

(acromioclavicular joint) (Greek,

akros = point)

ilium(N152,N174,

N248, TG6-

fan-shaped bone

that forms the

lateral prominence

one of three bones that form the

os coxae: ilium, ischium, pubis


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04) of the pelvis

iliac crest arching superioredge of the ilium

that forms the rimof the "fan"

attachment for abdominal wallmuscles

Muscles of the Back Region - Superficial Group

Muscle Origin Insertion ActionInnervati

onArtery Notes

Ima

ge

latissimu

s dorsi

(N174,

TG1-13)

vertebral

spines

from T7

to the

sacrum,

posteriorthird of

the iliac

crest,

lower 3

or 4 ribs,

sometim

es fromthe

inferiorangle of

the

scapula

floor of

the

intertuber

cular

groove

extends

and

rotates

the arm

mediall

y,along

with

adducti

on of

the arm

thoracodor

sal nerve

(C7,8)

from the

posterior

cord of thebrachial

plexus

thoracod

orsal a.

the

inserting

tendon

twists so

that fibers

originating highest

insert

lowest

(Latin,

latus =

broad,

dorsi =back)

levatorscapulae

(N424,TG1-13)

transverse

processesof C1-C4

vertebrae

medialborder of

thescapula

from thesuperior

angle tothe spine

elevates the

scapula

dorsalscapular

nerve(C5); the

upper partof the

musclereceives

branches

of C3 &

C4

dorsalscapular

a.

levatorscapulae

is namedfor its

action(Latin,

levator =to lift)

rhomboi

deus

major(N424,

TG1-13)

spines of

vertebrae

T2-T5

medial

border of

thescapula

inferior tothe spine

of the

retracts

,

elevates and

rotatesthe

scapula

dorsal

scapular

nerve (C5)

dorsal

scapular

a.

named for

its shape

(Greek,rhomb =

obliqueparallelog

ram)


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scapula inferior

ly

rhomboi

deusminor

(N424,TG1-13)

inferior

end ofthe

ligamentum

nuchae,

spines of

vertebrae

C7 and

T1

medial

border ofthe

scapula atthe root

of the

spine of

the

scapula

retracts

,elevate

s androtates

the

scapula

inferior

ly

dorsal

scapularnerve (C5)

dorsal

scapulara

named for

its shape(Greek,

rhomb =oblique

parallelog

ram

trapezius(N174,

TG1-13)

medialthird of

thesuperior

nuchalline,

externaloccipital

protubera

nce,

ligament

um

nuchae,

spinous

processes

of

vertebraeC7-T12

lateralthird of

theclavicle,

medialside of

theacromion

and the

upper

crest of

the

scapular

spine,

tubercle

of the

scapularspine

elevates and

depresses the

scapula(depen

ding onwhich

part of

the

muscle

contrac

ts);

rotates

the

scapula

superiorly;

retracts

scapula

motor:spinal

accessory(XI),

proprioception: C3-

C4

transverse

cervicala.

named forits shape;

trapeziusis an

exampleof a

musclethat

migrates

during

developm

ent from

its level

of origin

(cervical)

to its final

position,pulling its

nerve and

artery

alongbehind

Joints and Ligaments

Joint or

ligamentDescription Notes

nuchal

ligament

(N21,

TG1-09)

a midline ligament that extends

posteriorly from the spinous

processes of cervical vertebrae

and extends from the base of the

skull to the 7th cervical vertebra

a syndesmosis; it provides muscle

attachments to the cervical spinous

processes without the necessity of

long spinous processes that would

hinder extension of the neck(Latin,

nucha = nape)


7/9

Blood Vessels of the Back

Artery Source Branches Supply to Notes

dorsal scapular

(N33,N427,

N429,N430,N477,TG2-09)

subclavian

a., 3rd part

unnamed

muscular

branches

levator

scapulae m.,

rhomboideusmajor m.,

rhomboideus

minor m.

dorsal scapular a.

anastomoses with

the suprascapulara. and the

subscapular a. to

form the scapular

anastomosis;

dorsal scapular a is

a branch of thetransverse cervical

a. in ~30% of cases

thoracodorsal

(N429, TG1-13)

subscapular muscular latissimus

dorsi

transverse cervical

(N33,N177,N427,

TG1-13)

thyrocervical

trunk

unnamed

muscular

branches,

possibly

the dorsal

scapular a.

trapezius

muscle and

surrounding

tissues

transverse cervical

a. gives rise to the

dorsal scapular a.

~30% of the time

Nerves of the Back

Nerve Source

Branch

esM

otor Sensory Notes

accessory n.

(N177, TG7-

93C)

cranial

root:

medulla

-

nucleus

ambigu

us;

spinal

root:

spinal

nucleusof the

uppercervical

spinalcord

no

named

branche

s

GSE:

sternocleidomas

toid and

trapezius mm.

none also known as:

CN XI, 11th

cranial nerve;

spinal root

enters cranial

cavity by

passing through

the foramen

magnum; exits

skull by passing

through thejugular foramen;

accessory n. ismotor only; the

subtrapezialplexus of nerves

receivesproprioceptive


8/9

fibers: for the

sternocleidomas

toid m. from theventral primary

rami of spinalnn. C2 and C3 -

for trapezius viaventral primary

rami of C3 andC4

dorsal primary

ramus

(N258, TG1-

12)

first

branch

off of

the

dorsal

side of

the

spinalnerve

numero

us

to the deep back

mm.;

sympathetic

innervation to

the skin

general

sense

(touch,

pressure,

pain, heat,

cold, etc.)

to the skin

of the back

a mixed nerve

containing both

motor and

sensory fibers

(Latin, ramus =

branch)

dorsal scapular

n.

(N33,N427,N4

29,

N430,N477,

TG2-09)

brachial

plexus

(br. of

C5

ventral

primary

ramus)

no

named

branche

s

rhomboideus

major and minor

mm.; levator

scapulae m.

none dorsal scapular

n. passes

through the

scalenus medius

m.

occipital n.,

greater(N178, TG1-

16)

dorsal

primaryramus

ofspinal

nerveC2

(medialbr.)

no

namedbranche

s

posterior neck

muscles

skin of the

posteriorsurface of

the scalp

muscles

innervated bythis nerve

develop fromepimeres in the

embryo

spinal n.

(N258, TG1-

12)

formed

at the

point

wherethe

dorsal

and

ventralrootlets

meet; itends

where

dorsal

primary

ramus;

ventralprimary

ramus

to skeletal mm.;

some levels

carry

preganglionicsympathetic

axons (T1-L2)

general

sense

(touch,

pressure,pain, heat,

cold, etc.)

from the

entiresurface of

the neck,trunk and

extremities

located at the

intervertebral

foramen; there

are 31 pairs ofspinal nerves - 8

cervical, 12

thoracic, 5

lumbar, 5 sacral,1 coccygeal


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the

dorsal

andventral

primaryrami

diverge

; visceral

pain (via

the whiteramus

communicans and the

sympathetic nervous

system)

thoracodorsal

(middle

subscapular)

(N429, TG1-

13)

posterio

r cord of

brachial

plexus

latissimus dorsi

Clinical Terms

Term Definition

triangle of

auscultation

(N424, TG1-13)

a triangular gap formed by the superior horizontal border of the

latissimus dorsi, the medial border of the scapula, and the

inferolateral border of the trapezius; this is a good place to

examine posterior segments of the lungs with a stethoscope

lumbar triangle

(Petit'striangle)/hernia

(N174, TG1-13)

bordered medially by the latissimus dorsi, laterally by the

external abdominal oblique, and inferiorly by the iliac crest, thispoint is vulnerable to abdominal (lumbar) hernia. The definition

of a hernia is the protrusion of a portion of an organ or tissue

through an abnormal opening.

The material presented in these tables is contained in

the book:

MedCharts Anatomy by Thomas R. Gest & Jaye

Schlesinger

Published by ILOC, Inc., New York

Copyright 1995, unauthorized use prohibited.

The excellent editorial

assistance of

Dr. Pat Tank, UAMS

is gratefully acknowledged.

Copyright 2000 The University of Michigan.

Unauthorized use prohibited.

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