The Thorax
Compartments: these compartments are completely separate from one another
Compartment
Right Pleural
Cavity
Boundaries
Right root of neck
(slightly above rib
1—therefore
abnormal events
in neck can affect
it), right thoracic
wall,
mediastinum,
diaphragm.
It extends to rib 8
in the midclav.
line and to rib 10
in the mid ax. line,
crossing ribs 11
and 12 to reach
T12
Sternum to
thoracic vertebrae
(A to P), and from
the superior
thoracic aperture
to the inferior (S
to I)
Mediastinum
T4/5 separates
superior and
inferior parts. The
pericardium
separates it into
ant, post, and
med parts
Left root of neck
(slightly above rib
1), left thoracic
wall,
mediastinum,
diaphragm
Left Pleural Cavity
Contents
Right lung and its
recesses
(costodiaphragmatic
and
costomediastinal
recesses), right
hilum and lung root,
serous fluid in
pleural cavity
Heart, thymus,
esophagus, trachea,
major nerves
(phrenic, vagus),
and major systemic
blood vessels (aorta,
vena cavae,
pulmonary arteries
and veins, azygos
vein), and thoracic
duct
Left lung and its
recesses
(costodiaphragmatic
and
It extends to rib 8
costomediastinal
in the midclav.
recesses), left hilum
line and to rib 10
and lung root,
in the mid ax. line,
serous fluid in
Description
Clinical Points
Double sided
mesothelial
membranes
(pleura) with
parietal and
visceral layers
Recesses allow
accumulation and
aspiration of fluids
(hemothorax,
pheumothorax,
thoracocentesis
Thick, flexible,
soft tissue
partition sitting
longitudinally in
the median
sagittal position
Double sided
mesothelial
membranes
(pleura) with
parietal and
visceral layers
Pericarditis
(inflammation if
the pericardium),
Constrictive
Pericarditis (look
for Kussmaul’s
sign), Pericardial
effusion (excess
fluid in the
pericardial space)
leading to Cardiac
Tamponade,
Pericardiocentesis
Left lung is smaller
to accommodate
the heart (cardiac
notch)
crossing ribs 11
pleural cavity
and 12 to reach
T12
Bones of the Thorax: Vertebrae, discs, ribs, and sternum
Bone (group)
Thoracic
Vertebrae
True Ribs
False and Floating
Ribs
Sternum
Structures/Parts
Bodies, spinous
processes,
pedicles, lamina,
transverse
processes, sup.
And inf. articular
processes
Head (2 articular
facets separated
by a crest), neck,
tubercle( rib 1 has
scalene tubercle),
angle, costal
groove, costal
cartilage
Interchondral
joints attach ribs
to eachother in
the anterior wall
(7-10)
Manubrium
(jugular notch),
body (transverse
ridges from
sternbrae), and
xiphoid process
Number
12
Ribs 1-7
Ribs 8-12 (11 and
12 are floating)
3 parts
Articulations
Ribs: superior
(own rib) and
inferior (rib below)
costal demifacets,
transverse costal
facet (own rib)
Exceptions: T1,
T10-T12
Clinical Issues
Disc protrusions,
vertebral fractures
and displacements
T1-7
(costotransverse
and with vertebral
body), articulate
directly with
sternum
Flail chest, cervical
ribs (thoracic
outlet syndromestress on brachial
plexus and
subclavian vessels)
8-10 articulate
with T 8-10 and
costal cartilage of
the true ribs
11-12 only
articulate with T11
and T12
Manubrium with
clavicle and ribs 1
and 2, body with
ribs 2-7, xiphoid
with rib 7
Bone marrow
samples
Sternal angle used
for reference to
find T4/T5 level
and 2nd rib
Important Nerves:
Nerve
Vagus
Phrenic
Innervation
Lung (parasympathetic: constricts bronchioles),
visceral pleura, esophagus, stomach, cardiac
plexus supplies heart, recurrent laryngeal nerve
goes to larynx
The entire Diaphragm, and the fibrous and parietal
pericardium
Breast (anterior and lateral cutaneous branches of
Intercostals
Spinal Nerves T1 to L2
the 2nd to 6th), Intercostal muscles, subcostales,
transverses thoracis, dermatomes of thorax (4th:
nipples, 10th: umbilicus, 12th: ASIS) and parietal
pleura
All preganglionic sympathetic nerve fibers
(sympathetic system dilates the bronchioles.
Greater, lesser and least splanchnic nerves branch
from the lower 7 ganglia and supply the viscera of
the abdomen and pelvis
Muscles of the Thorax:
Muscle
Pectoralis Major
Pectoralis Minor
Subclavius
External
Intercostals
Internal
Intercostals
Innermost
Intercostals
Attachments
Medial clavical,
sternum, and
costal cartilages to
lateral lip of
intertubercular
sulcus of humerus
anterior surface of
ribs 3-5 to the
coracoid process
Anterior and
medial aspect of
rib 1 to the
inferior clavicle
Inferior margin of
rib above to
superior margin of
rib below
Lateral edge of
costal groove of
rib above to
superior margin of
rib below, deep to
ext. intercostal
Medial edge of
costal groove of
rib above to
internal aspect of
superior margin of
rib below
Internal surface
Innervation
Action
Clinical Issues
Medial and Lateral
Pectoral nerves
Flexes, adducts,
and medially
rotates the arm
Directly underlies
the breast, forms
anterior wall of
axilla
Medial Pectoral
nerve
Pull tip of shoulder
inferiorly
Nerve to
subclavius (C5, C6)
Pull tip of shoulder
inferiorly
Intercostal Nerves
(T1-T11)
Most active during
inspiration, moves
ribs superiorly
Intercostal Nerves
(T1-T11)
Most active during
expiration, moves
ribs inferiorly
Intercostal Nerves
(T1-T11)
Act with internal
intercostals
Enclosed by
clavipectoral
fascia, forms
anterior wall of
axilla
Enclosed by
clavipectoral
fascia, forms
anterior wall of
axilla
Thoracotomy
(incision through
intercostal space),
chest tubes
Thoracotomy
(incision through
intercostal space),
chest tubes
Intercostal veins,
arteries, and
nerves run
between this layer
of muscle and the
int. intercostals
along inf. rib edge
Subcostales
Transversus
thoracis
near angle of
lower ribs to
internal surface of
2nd or 3rd rib below
Int. surfaces of c.
cartilages of 2nd to
6th ribs to deep
sternum, xiphoid
process and c.
cartilages ribs 4-7
Related intercostal
nerves
May depress ribs
Related intercostal
nerves
Depresses costal
cartilages
Secure the
internal thoracic
vessels to the
anterior chest wall
The Diaphragm
Attachments
The diaphragm
attaches
peripherally to the
xiphoid process,
costal margin of
the thoracic wall,
ends of ribs 11 and
12, vertebrae of
lumbar region,
and ligaments that
span the posterior
abdominal wall
and the fibers
converge to form
the central tendon
Innervation
Right and Left
Phrenic nerves
(C3, C4, C5)
Action
Clinical Significance
Contraction of the
diaphragm flattens
its structure and
increases thoracic
volume, essential
to normal
inspiration
Structures passing through the
diaphragm: aorta (T12), Thoracic
duct (T12), Azygos and
hemiazygos veins (T12), Inferior
vena cava (T8), esophagus (T10),
vagus nerve (T10)
The Lungs:
Right Lung
Left Lung
Features
3 lobes separated
by the oblique and
horizontal fissures,
hilum and
pulmonary
ligament
2 lobes separated
by the oblique
fissure, cardiac
notch and lingual
to accommodate
the heart, hilum
Related Structures
Heart, inferior
vena cava,
superior vena
cava, azygos vein,
esophagus
Heart, aortic arch,
thoracic aorta,
esophagus
Root Contents
Right pulmonary
artery, right
pulmonary veins,
right main
bronchus,
bronchial vessels,
nerves, lymphatics
Left pulmonary
artery, left
pulmonary veins,
left main
bronchus,
bronchial vessels,
Clinical Issues
Right lung is more
likely to receive
aspirated objects
because the right
primary bronchus
is wider, shorter,
and more vertical
Lung cancer, chest
wounds,
pneumothorax,
hemothorax,
pneumonia
and pulmonary
ligament
nerves, lymphatics
The Heart:
Chamber
Right Atrium
Right Ventricle
Left Atrium
Left Ventricle
Features
Forms right border of heart,
receives blood from venae cavae
and coronary sinus, Crista
terminalis, right auricle, interatrial
septum with fossa ovalis
Forms most of anterior surface,
receives blood from the right
atrium, infundibulum, papillary
muscles, trabeculae carneae,
chordate tendineae, moderator
band (carries right bundle branch)
Forms most of base of heart,
receives the 4 pulmonary veins,
interatrial septum with fossa ovale,
left auricle,
Forms the apex, and contributes to
the anterior surface, has fine and
delicate trabeculae carneae,
anterior and posterior papillary
muscles, Interventricular septum
(membranous and muscular)
Membranous aspect of septum is
most common site of VSDs
Valves
Right AV valve
(tricuspid)
delivers blood to
right ventricle
Right AV valve
(tricuspid),
Pulmonary
Semilunar Valve
delivers blood to
pulmonary trunk
Left AV Valve
(Mitral
Valve)delivers
blood to left
ventricle
Left AV Valve
(Mitral Valve)
Aortic Semilunar
Valve delivers
blood to aorta
and coronary
arteries (right
and left)
Clinical Significance
Contains SA node
Valve disease usually
caused by infection
Valve disease usually
caused by infection
Mitral Valve Disease
(stenosis and
regurgitation) leads to
hypertrophy of left
ventricle and atrium
Thickest walled
chamber
Mitral Valve Disease
leads to hypertrophy of
left ventricle and atrium
Mitral is Most
commonly diseased!
Coronary Vasculature: The Coronary Arteries and Cardiac Veins
Vessel
Right Coronary Artery
Left Coronary Artery
Branches
Sinu-atrial nodal
branch, Right
Marginal branch,
Posterior
Interventricular
branch (PDA)
Location
Passes anteriorly and to
the right between the
right auricle and the
pulmonary trunk and
then descends vertically
in the coronary sulcus
Supplied Area of Heart
Right atrium and right
ventricle, SA and AV
nodes, interatrial
septum, and portions of
the left atrium, IV
septum, and left
ventricle
Anterior
Interventricular
branch (LAD) which
gives off 1 or 2
Diagonal Branches
Passes between
pulmonary trunk and the
left auricle before
Most of the Left atrium
and ventricle and the IV
septum (including the
entering the coronary
sulcus
Circumflex Branch
which gives off the
Left Marginal Branch
An enlargement of
the Great Cardiac
Vein
Coronary Sinus
Great Cardiac Vein
Middle Cardiac Vein
Small Cardiac Vein
Posterior Cardiac Vein
Posterior coronary
sulcus
Begins at apex of the
heart, ascends in the
anterior interventricular
sulcus, then the
coronary sulcus where it
turns left onto the base
of the heart and enlarges
to form the coronary
sinus
Begins at apex of heart
and ascends in the
posterior
interventricular sulcus to
the coronary sinus
Begins in the lower
anterior coronary sulcus
between the right
atrium and ventricle and
goes to coronary sinus
Lies on the posterior
surface of the left
ventricle and shunts to
coronary sinus or great
cardiac vein
bundle of His and its
branches)
Receives four main
tributaries (great,
middle, small, and
posterior) drains into
the right atrium
Drains the anterior apex
of the heart
Drains the posterior
apex of the heart
Drains inferior right
portion of heart
Drains posterior left
ventricle
Autonomic Nervous System: Monitor and regulate function and blood flow to viscera
Preganglionic: inside the CNS, Postganglionic: outside of CNS
Posterior Root: sensory (afferent), Anterior Root: motor (efferent)
Parts/Divisions
GVAs
Neurons
Utilized
Do NOT
synapse
1 cell body in
sensory ganglia
2 cell bodies
Signal Type
Origins
Sensory
(receptors)
Preexisting pathways
(same levels as GVEs)
[SAME DAVE]
Locations
ANS
GVEs
(one in CNS
and one in
periphery, or
ganglia)
Secretory and
Motor
(smooth
muscle)
Preexisting pathways
(same levels as GVAs)
ANS
IML
Fight or flight
Sympathetic
Motor and
sensory
Rest and
digest
Parasympathetic
Motor and
sensory
Arise from T1-L2 (white
rami)and the axons go
everywhere (superficial
and deep)
Arise from craniosacral
CNS (CNs 3,7,9,10 and
S2-4) regions
Paravertebral
sympathetic trunk
extends from base of
skull to coccyx,
connected to anterior
rami by white
(preganglionic) and
gray (post ganglionic)
rami communicans
IML-like area in sacral
region
and only go deep,
NOT to skin