2. The muscles of thorax
Extrinsic muscles
Pectoralis major
Pectoralis minor
Serratus anterior
Intrinsic muscles
Intercostales externi
Intercostales interni
Intercostales intimi
Transverses thoracis
2
3. Intercostales externi
Origin: lower border of riⅡ)
Insertion: upper border of rib
below origin
Action: elevate ribs adding
in forced inspiration
Replaced anteriorly by
external intercostals
membrane.
Intercostales interni
Origin: upper border of rib
Insertion: lower border of rib
above origin
Action: depress ribs for
forced expiration
Replaced posteriorly by
internal intercostals
membrane.
3
4. Diaphragm
Shape and position:
dome-shaped between thorax and
abdomen, consists of a peripheral
muscular part and a central
tendon
Origin
Sternal part: xiphoid process
Costal part: lower six and costal
cartilages
Lumbar part: arises by two crura
from upper 2-3 lumbar vertebrae
Insertion: central tendon
Weak areas: triangular spaces
without muscular tissue
Lumbocostal triangle: between
costal and lumbar parts.
Sternocostal triangle: between
costal and sternal parts.
4
5. Openings in the diaphragm
Aortic hiatus－lies anterior to the body of the 12th
thoracic vertebra between the crura. It transmits the
aorta, thoracic duct
Esophageal hiatus －for esophagus and vagus nerves
at level of T10.
Vena cava foramen －for inferior vena cava, through
central tendon at T8 level
5
T8
T10
T12
6. Action:
Contraction: the dome
moving downward,
increases the volume of
thoracic cavity which
results in inspiration, at
the same time the intra-abdominal
pressure is
increased assists in
defecation, vomiting or
child birth.
Relaxation: the dome
returns to the former
position, reduces the
volume to the thoracic
cavity, resulting in
expiration.
6
7. Arteries of thorax
Pulmonary trunk
Arises from right ventricle
Runs up, back ,and to the left
Bifurcates inferior to aortic arch
into right and left pulmonary
arteries, one for each lung
Pulmonary arteries
Right pulmonary artery－passes
posterior to ascending aorta
and superior vena cava to
hilum of right lung
Left pulmonary artery－passes
anterior to descending aorta
and left main bronchus to hilum
of left lung
7
8. Arterial ligament － remnant of ductus arteriosus, connects
bifurcation of pulmonary trunk to inferior border of aortic
arch
Triangule of ductus arteriosus
Bounded by phrenic n., left vagus n. and left pulmonary a.
Contents－ arterial ligament , left recurrent n. and superficial
cardiac plexuses
8
9. Ascending aorta
Runs upward, forward
and to the right,
Extends to level of
second right
sternocostal joint
Branches: right and
left coronary arteries
9
10. Aortic arch
Continuation of ascending aorta
Curves upward, to the left and
posteriorly, then downward,
arching over left principal
bronchus and pulmonary trunk to
lower border of T4 level, to
become descending aorta
Branches (from right to left )
Brachiocephalic trunk－extends
to right sternoclavicular joint,
bifurcates into right subclavian
and right common carotid
arteries
Left common carotid artery
Left subclavian artery
Aortic isthmus－baroreceptor
Aortic glomera－chemoreceptor
10
11. Thoracic aorta
Continuation of aortic arch at lower border of T4
Courses downward on left side of, then in front of
vertebral column
Passes through aortic hiatus of diaphragm at
level of T12 vertebra to enter abdominal cavity
Main branches
Parietal branches
Nine pairs posterior intercostals arteries
One pair subcostal artery
For lower nine intercostals spaces and
upper part of abdominal wall; superior
phrenic arteries supply the superior
surface of the diaphragm.
Visceral branches
Bronchial branches: one or two for each
lung
Esophageal branches
Pericardial branches
11
12. Internal thoracic artery －
descends into thorax
1.2cm lateral to edge
of sternum, and ends
at the sixth costal
cartilage by dividing
musculophrenic and
superior epigastric
arteries
12
14. Veins of thorax
Brachiocephalic veins
Formed by union of internal jugular and
subclavian veins posterior to the
sternoclavicular joint
Angle of union is termed venous angle
Superior vena cava
Formed by union of right and left
brachiocephalic veins behind the right
sternocostal synchorndrosis of first rib
Runs vertically down on right of
ascending aorta
Joined by azygos vein at level of sternal
angle
Enters right atrium at lever of lower
border of third right sternocostal joint
Collects blood from veins of upper half
of body
14
15. Azygos vein
Begins as continuation of right
ascending lumbar vein
Ascending along the right side of
vertebral column
Joins superior vena cava by
aching above right lung root at
level of T4 to T5
Receives right posterior intercostals
and subcostal veins plus some of
bronchial, esophageal and
pericardial veins, and hemiazygos
vein
Tributaries－hemiazygosv. and
accessory hemiazygos v. which
receive most left posterior
intercostals vein and left bronchial
veins
15
16. Veins of vertebral column
Consists of
External vertebral
venous plexus
Internal vertebral
venous plexus
16
17. The lymphatic drainage of thorax
The lymphatic drainage of thoracic
wall
To axillary lymph nodes
To parasternal lymph
nodes (along internal
thoracic vessels)
To intercostals lymph
nodes from deeper
structures
17
18. lymph nodes of the thoracic contents
lymph nodes of trachea,
bronchi and lungs
Pulmonary lymph nodes lie in
the angles of bifurcation of
branching lobar bronchi
Bronchopulmonary hilar lymph
nodes－lie in the hilus of the
lung
Tracheobronchial lymph nodes
－situated above or below the
bifurcation of trachea
Paratracheal lymph nodes
－along each side of the
trachea
18
19. Anterior mediastinal
lymph node lies anterior
to the large blood vessels of
thoracic cavity and
pericardium; the efferents
unite with those of
paratracheal lymph nodes,
to form the right and left
bronchomediastinal trunks .
The left bronchomediastinal
trunk terminates in thoracic
duct, and right in the right
lymphtic duct
Posterior mediastinal
lymph nodes lie along
the esophagus and thoracic
aorta
19
20. Thoracic duct
Begins in front of L1 as a dilated sac,
the cisterna chyli, which formed by
joining of left and right lumbar trunks
and intestinal trunk
Enter thoracic cavity by passing
through the aortic hiatus of the
diaphragm and ascends along on the
front of the vertebral column,
between thoracic aorta and azygos
vein
Travels upward, veering to the left at
the level of T5
At the roof of the neck, it turns laterally
and arches forwards and descends to
enter the left venous angle
20
21. Just before termination, it receives
the left jugular, subclavian and
bronchomediastinal trunks
Drains lymph from lower limbs,
pelvic cavity, abdominal cavity,
left side of thorax, and left side of
the head, neck and left upper limb
Right lymphatic duct
Formed by union of right jugular,
subclavian, and
bronchomediastinal trunks
Ends by entering the right venous
angle
Receives lymph from right half of
head, neck, thorax and right upper
limb
21
22. Anterior branches of thoracic nerves
Intercostal nerves (anterior rami of
T1- T11): runs forward inferiorly to
intercostals vessels in costal groove
of corresponding rib, between
intercostals externi and intercostals
interni; first six nerves are distributed
within their intercostals space,
lower five intercostals nerves leave
anterior ends of their intercostals
spaces to enter abdominal wall
Subcostal nerve (anterior ramus of
T12): follows inferior border of T12
rib and passes into abdominal wall
Distribution: distributed to
intercostales and anterolateral
abdominal muscles, skin of
thoracic and abdominal wall,
parietal pleura and peritoneum
22
23. The segmental innervation of anterior surface of
trunk
T2－sternal angle
T4－ nipple
T6－xiphoid process
T8－costal arch
T10－umbilicus
T12－midpoint between umbilicus
and symphysis pubis
23
25. Phrenic nerve
Descends over scalenus
anterior to enter thorax
Accompanied by
pericardiophrenic vessels
and passes anterior to lung
roots between mediastinal
pleura and pericardium to
supply motor and sensory
innervation to diaphragm
Sensory fibers supply to
pleurae, pericardium and
peritoneum of diaphragm;
usually right phrenic nerve
may be distributed on live,
gallbladder and biliary
system.
25
26. Left vagus nerve
Enter thoracic inlet between left
common carotid and left
subclavian arteries, posterior to
left brachiocephalic vein
Crosses aortic arch where left
recurrent laryngeal nerve
branches off
Passes posterior to left lung root
Forms anterior esophageal plexus
Forms anterior vagal trunk at
esophageal hiatus where it
leaves thorax and passes into
abdominal cavity , then divides
into anterior gastric and hepatic
branches
26
27. Right vagus nerve
Enter thoracic inlet on right
side of trachea
Travels downward posterior
to right brachiocephalic vein
and superior vena cava
Passes posterior to right lung
root
Forms posterior esophageal
plexus
Forms posterior vagal trunk at
esophageal hiatus where it
leaves thorax and passes into
abdominal cavity, then
divides into posterior gastric
and celiac branches
27
28. 28
Recurrent laryngeal nerves
Right one hooks around right
subclavian artery, left one hooks
aortic arch
Both ascend in tracheo-esophageal
groove
Nerves enter larynx posterior to
cricothyroid joint, the nerve is
now called inferior laryngeal
nerve
Innervations: laryngeal mucosa
below fissure of glottis , all
laryngeal laryngeal muscles
except cricothyroid
Bronchial and esophageal
branches
29. 29 Thoracic sympathetic trunk
Branches of sympathetic trunk to
thoracic plexuses
Greater splanchnic nerve formed by
preganglionic fibers from T5~T9
ganglia, and relay in celiac ganglion.
Lesser splanchnic nerve formed by
preganglionic fibers from T10~T12
ganglia, and relay in aorticorenal
ganglion.
The postganglionic fibers supply the
liver, spleen, kidney and alimentary
tract as far as the left colic flexure.
31. Parts and regions of the thorax
Boundaries
Superior－jugular notch,
sternoclavicular joint, superior
border of clavicle, acromion,
spinous processes of C7
Inferior－xiphoid process, costal
arch, 12th and 11th ribs, vertebra
T12
Regions
Thoracic wall
Thoracic cavity
31
32. Landmarks
Jugular notch corresponds with
The 2th thoracic vertebra in
male, the 3th thoracic
vertebra in female
Sternal angle connects 2nd
costal cartilage laterally，
corresponds with
The lower border of 4th
thoracic vertebra
The bifurcation of trachea in
the adult
The beginning of aortic arch
which ends posteriorly at the
same level
The esophagus is crossed by
the left main bronchus
32
33. Xiphoid process－phisternal
junction lies
opposite the body of the
9th thoracic vertebra
Clavicle
Inferior fossa of clavicle
Coracoid process
Ribs and intercostal
spaces
Costal arch
Infrasternal angle
Xiphocostal angle
Papillae
33
34. Thoracic wall
Skin
Superficial fascia
Thoracoepigastric v.
Supraclavicular n.
Anterior and lateral cutaneous
branches of intercostal n.
Deep fascia
34
35. Intercostal space
35
Posterior intercostal v.
Posterior intercostal a.
Intercostal n.
36. Lymphatic drainage of breast
Into pectoral ln. from lateral
and central parts of breast
Into apical and supraclavicular
ln. from superior part of breast
Into parasternal ln. from medial
part of breast
Into interpectoral ln. from deep
part of breast
The lymphatic capillaries of
breast form an anastomosing
network which is continuous
across the midline with that of
the opposite side and with that
of the abdominal wall
36
38. The Mediastinum
Concept－all of
organs between the
left and right
mediastinal pleurae is
called mediastinum.
It extends from the
sternum in front to the
vertebral column
behind, and from the
thoracic inlet above
to the diaphragm
below.
38
39. Subdivisions of mediastinum
Superior mediastinum
Inferior mediastinum
Anterior mediastinum
Middle mediastinum
Posterior mediastinum
39
40. Left side of mediastnum 40
Left vagus n.
Left subclavian a.
Thoracic duct
Aortic arch
Left recurrent n. Thoracic aorta
Phrenic n. &
pericardiacophrenic a.
Root of lung
Pericardium
Sympathetic trunk
Greater splanchnic n
Esophagus
41. Right side of mediastnum 41
Superior vena cava
Phrenic n. &
pericardiacophrenic a.
Root of lung
Pericardium
Trachea
Left vagus n.
Arch of azygos v.
Azygos v.
Sympathetic trunk
Esophagus
Inferior vena cava
42. Superior mediastinum
Locating－from inlet of thorax
to plane extending from
level of sternal angle
anteriorly to lower border of
T4 vertebra posterioly
Contents
Superficial layer
Thymus
Three veins
Left brachiocephelic v.
Right brachiocephelic v.
Superior vena cava
42
43. Middle layer
Aotic arch and its
three branches
Phrenic n.
Vagus n.
43
45. Relations of aortic arch
Anteriorly and to the left －
pleura, lung，phrenic n.,
pericardiacophrenic vessels
and vagus n.
Posteriorly and to the right－trachea,
esophagus, left
recurrent n., thoracic duct,
deep cardiac plexus
Superiorly－its three branches,
left brachiocephalic v. and
thymus
Inferiorly－pulmonary a.,
arterial ligament, left recurrent
n., left principal bronchus and
superficial cardiac plexus
45
46. Triangule of ductus arteriosus
Bounded by phrenic n., left vagus
n. and left pulmonary a.
Contents－ arterial ligament , left
recurrent n. and superficial
cardiac plexuses
46
47. Inferior mediastinum
Anterior mediastinum
Location－posterior to body
of sternum and attached
costal cartilages, anterior to
heart and pericardium
Contents－fat, remnants of
thymus gland, anterior
mediastinal lymph nodes
47
48. Middle mediastinum
Location－between
anterior mediastinum
and posterior
mediastinum
Contents: hart and
pericardium, beginning
or termination of great
vessels, phrenic nerves,
pericardiacophrenic
vessels , lymph nodes,
48
49. Posterior mediastinum
Location－posterior to heart
and pericardium, anterior to
vertebrae T5－T12
Contents: esophagus, vagus
n., thoracic aorta, azygos
system of veins, thoracic
duct, thoracic sympathetic
trunk, posterior mediastinal
lymph nodes
49
50. Relations of esophagus
Anteriorly－trachea,
bifurcation of trachea, left
principal branchus, left
recurrent n., right
pulmonary a., anterior
esophageal plexus,
pericardium, left atrium,
diaphragm
50
51. Posteriorly－posterior
esophageal plexus, thoracic
aorta, thoracic duct, azygos
v., hemiazygos v.,accessory
hemiazygos v., right posterior
intercostal v.
51
52. Left－left common carotid a., left subclavian a., aortic
arch, thoracic aorta, superior part of thoracic duct
Right－arch of azygos v.
52
53. Relations of thoracic aorta
Anteriorly－left root of lung,
pericardium and esophagus
Posterior－ hemiazygos v.,
accessory hemiazygos v.,
Right－azygos v. and thoracic
duct
Left－mediastinal pleura
53
54. Mediastinal spaces
Retrosternal space －lies
beween sternum and
endothoracic fascia
Pretracheal space －lies within
superior mediastinum,
between trachea, bifurcation
of trachea and aortic arch
Retroesophagus space －
lies within superior
mediastinum, beween
esophagus and endothoracic
fascia
54
