anatomy of rEspiratory system

1. Module: Respiratory system
Anatomy of the respiratory
system
Compiled by Dr. Girmay (Anatomist & MD)

2. Introduction: The respiratory system
• It is the system that provides the route by which the supply of oxygen
present in the atmospheric air enters the body, and it provides the route of
excretion for carbon dioxide
• The condition of the atmospheric air entering the body varies
considerably according to the external environment, e.g. it may be dry
or moist, warm or cold, and carry varying quantities of pollutants, dust
or dirt.
• As the air breathed in moves through the air passages to reach the lungs,
it is warmed or cooled to body temperature, saturated with water
vapour and ‘cleaned’ as particles of dust stick to the mucus which
coats the lining membranes

3. Introduction cont…
• Respiration: it is the term used to describe two different but
interrelated processes of exchange of gases
1. External respiration: exchange of gases between the blood and
the lungs
2. Internal respiration: exchange of gases between the blood and the
cells
• the series of intracellular biochemical processes by which the cell produces
energy by metabolism of organic molecules

4. Goals of respiration
–Pulmonary ventilation
• Air moves in and out of lungs
• Continuous replacement of gases in
alveoli (air sacs)
–External respiration
• Gas exchange between blood and air at
alveoli
• O2 (oxygen) in air diffuses into blood
• CO2 (carbon dioxide) in blood diffuses
into air
–Transport of respiratory
gases
•Between the lungs and the cells of the
body
•Performed by the cardiovascular system
•Blood is the transporting fluid
–Internal respiration
•Gas exchange in capillaries between
blood and tissue cells
•O2 in blood diffuses into tissues
• Goals: to provide oxygen to the tissues and to remove carbon dioxide
• To achieve these goals, respiration can be divided into four major
functions:

5. Other Functions of the Respiratory System
• Regulation of blood pH
–The respiratory system can alter blood pH by changing
dioxide levels
• Voice production
–Air movement past the vocal folds makes sound and speech
• Olfaction
–The sensation of smell occurs when airborne molecules are
into the nasal cavity
• Protection
–The respiratory system provides protection against some
microorganisms by preventing their entry into the body and
removing them from respiratory surfaces

6. Organs and classification of respiratory
system
• The organs of the respiratory system and Structural classification
• nose
• pharynx
• larynx
• trachea
• two bronchi (one bronchus to each lung)
• bronchioles and smaller air passages
• two lungs and their coverings, the pleura
• muscles of breathing – the intercostal muscles and the diaphragm
Upper respiratory tract
Lower respiratory tract

7. Organs of respiratory system cont…
• The organs of the respiratory system and
functional classification
• Conducting zone
• nose, pharynx, larynx, trachea, bronchi,
bronchioles and terminal bronchioles
• Filters, humidifies and warms air
• Respiratory zone
• Respiratory bronchioles

Alveolar ducts

Alveolar sacs

Alveoli

8. The nose and nasal cavity
• The nose is the part of the respiratory tract superior to the hard palate and
contains the peripheral organ of smell
• It includes
• the external nose and
• nasal cavity: divided into right and left cavities by the nasal septum
• The functions of the nose include
• olfaction (smelling),
• respiration (breathing),
• filtration of dust,
• humidification of inspired air, and
• reception and elimination of secretions from the paranasal sinuses and nasolacrimal
ducts

9. The nose cont…
• External Nose
• is the visible portion that projects from the
face; its skeleton is mainly cartilaginous
• The dorsum of the nose extends from the root
of the nose to the apex(tip) of the nose
• The inferior surface of the nose is pierced by
two piriform (L. pear-shaped) openings, the
nares(nostrils, anterior nasal apertures),

10. The nose cont…
• SKELETON OF EXTERNAL NOSE
• Parts – dorsum, root, apex
• The supporting skeleton of the nose is
composed of
• Bone: nasal bones, frontal processes of the
maxillae, the nasal part of the frontal bone
and its nasal spine, and the bony parts of the
nasal septum
• hyaline cartilage: consists of five main
cartilages:
• two lateral cartilages,
• two alar cartilages: are U-shaped, free
and movable; they dilate or constrict the
nares when the muscles acting on the
nose contract

11. The nose cont…
• internal portion (nasal cavities):-
divided into right and left cavities by
nasal septum
• Each nasal cavity is divisible into
• an olfactory area: contains the
peripheral organ of smell
• a respiratory area
• The nasal septum
• The septum has a bony part and
soft mobile cartilaginous part.
• The main components of the
septum are
• the perpendicular plate of the
• the vomer, and
• the septal cartilage.

12. The nose cont…
• The nasal cavity cont…
• is entered anteriorly through the nares(nostrils)
• It opens posteriorly into the nasopharynx through the choanae
• Mucosa lines the nasal cavity, except for the nasal vestibule, which is lined with skin
• The nasal mucosa
• is firmly bound to the periosteum and perichondrium of the supporting bones and
cartilages of the nose
• is continuous with the lining of all the chambers with which the nasal cavities
communicate:
• the nasopharynx posteriorly,
• the paranasal sinuses superiorly and laterally, and
• the lacrimal sac and conjunctiva superiorly.
• The inferior two thirds of the nasal mucosa is the respiratory area, and the
superior one third is the olfactory area

13. The nose cont… BOUNDARIES OF NASAL CAVITIES
• The roof of the nasal cavities
• is curved and narrow, except at its posterior end, where the hollow body of the sphenoid
forms the roof
• It is divided into three parts (frontonasal, ethmoidal, and sphenoidal) named from the
bones forming each part
• The floor of the nasal cavities
• is wider than the roof
• is formed by the palatine processes of the maxilla and the horizontal plates of the
palatine bone
• The medial wall of the nasal cavities:
• is formed by the nasal septum.
• The lateral walls of the nasal cavities
• are irregular owing to three bony plates, the nasal conchae, which project inferiorly,
somewhat like louvers

14. Boundaries of the nasal cavities
A: roof
B: floor
C. Lateral
D. Medial

15. • Features of the
lateral wall of
nasal cavity
• Conchae
• bony projections
the lateral wall
the nasal cavity
• directed
downwards and
medially
• middle and
superior conchae
are processes of
ethmoid while
inferior one is a

16. • Meatus
• Spheno-ethmoidal
recess - space
between the roof of
the nasal cavity
the superior
feature opening of
spenoidal sinus
• Space between
conchae and
lateral wall of the
nasal cavity
• Superior meatus –
below superior
concha; feature
opening of
ethmoidal sinus
16
• Middle meatus – under middle conchae
• Presents round elevation called bulla ethmoidalis produced by the middle ethmoidal
air sinus
• There is a semilunar groove called hiatus semilunaris below and in front of the bulla

17. • Lateral wall of the nasal
cavity
• Openings of the
paranasal sinuses
• Frontal sinus drains into
the superior aspect of
the hiatus semilunaris
• Anterior and middle
ethmoidal air sinuses
drain through openings
of the ethmoidal bulla
on superoposterior
aspect of the hiatus
semilunaris
• Posterior ethmoidal
sinus – in to the superior
meatus
17
• Maxillary air sinus has its ostium directly inferior to the ethmoid bulla within the hiatus
semilunaris
• Sphenoid sinus - sphenoethmoidal recess

19. • Foramina opening in the
nasal cavity
1. Nasolacrimal duct - to
the inferior meatus
2. Incisive foramina - in
the anterior floor of the
which transmits the
sphenopalatine and
parts of the greater
vessels
3. Olfactory foramina - in
the cribriform plate of
ethmoid - transmit
nerves
4. Sphenopalatine foramen
- connects the posterior
of the superior meatus
pterygopalatine fossa. It
transmits
vessels and nasopalatine
superior nasal nerves 19

20. The arterial supply of the medial and lateral walls of the
nasal cavity is from five sources:
1. Anterior ethmoidal artery(from the ophthalmic artery).
2. Posterior ethmoidal artery(from the ophthalmic artery).
3. Sphenopalatine artery(from the maxillary artery).
4. Greater palatine artery(from the maxillary artery).
5. Septal branch of the superior labial artery(from the facial
• The first
three
arteries
divide into
lateral and
medial
(septal)
branches
• The greater
palatine
artery
reaches the
septum via
the incisive
• The anterior part of the
nasal septum is the site of
an anastomotic arterial
plexus involving all five
arteries supplying the
septum (Kiesselbach area)

21. • Veins – do not run parallel to the arteries but correspond arteriovenous territories of
the face
• Fronto-median region including the nose drain to end in facial vein
• Orbitopalpebral area of face including the root of nose drains to the ophthalmic veins
• A rich submucosal venous plexus,deep to the nasal mucosa, provides venous
drainage of the nose via the sphenopalatine, facial, and ophthalmic veins.
• The plexus is an important part of the body’s thermoregulatory system, exchanging
heat and warming air before it enters the lungs
• Venous blood from the external nose drains mostly into the facial vein via the
angular and lateral nasal veins
• However, recall that it lies within the “danger area” of the face because of communications with
the cavernous(dural venous) sinus
• Lymphatics –
• primarly to submandibular although from root of nose drains to superficial parotid lymph
nodes

22. • Innervation of nasal cavity
• A dashed line extrapolated approximately from the spheno-ethmoidal recess to the apex of the nose
demarcates the territories of the ophthalmic (CN V1) and maxillary (CN V2) nerves for supplying
general sensation to both the lateral wall and the nasal septum.
• The olfactory nerve (CN I) is distributed to the olfactory mucosa superior to the level of the superior
concha on both the lateral wall and the nasal septum

23. • Parasympathetic innervation
• Secretomotor innervation of mucous glands in the nasal cavities and paranasal
sinuses is by preganglionic parasympathetic fibers carried in the greater petrosal
branch of the facial nerve
• These fibers enter the pterygopalatine fossa and synapse in the pterygopalatine
ganglion
• Postganglionic parasympathetic fibers then join branches of the maxillary
nerve [V2] to leave the fossa and ultimately reach target glands
23

24. • Sympathetic innervation
• Sympathetic innervation, mainly involved with regulating blood flow in the nasal
mucosa,
• is from the spinal cord level T1
• Preganglionic sympathetic fibers enter the sympathetic trunk and ascend to synapse in
the superior cervical ganglion
• Postganglionic sympathetic fibers pass onto the internal carotid artery, enter the
cranial cavity, and then leave the internal carotid artery to form the deep petrosal
nerve, which joins the greater petrosal nerve of the facial nerve and enters the
pterygopalatine fossa
• Like the parasympathetic fibers, the sympathetic fibers follow branches of the
maxillary nerve [V2] into the nasal cavity
24

25. Paranasal Sinuses
• The paranasal sinuses are air-filled extensions of the respiratory
part of the nasal cavity into the following cranial bones:
• frontal, ethmoid, sphenoid, and maxilla.
• They are named according to the bones in which they are located
(Frontal, ethmoidal, sphenoid and maxillary sinusus )
• These cavities are lined by the respiratory epithelium
• All open to nasal cavity
• They are absent at birth, enlarging full size at puberty
• Receive sensory nerves from the branches of the trigeminal nerve
• Functions of the paranasal sinuses
• Make skull lighter
• Increase the resonance of sound

26. Paranasal sinuses

27. • FRONTAL SINUSES
• The right and left frontal sinuses are between the outer and inner tables of the
frontal bone, posterior to the superciliary arches and the root of the nose
• Frontal sinuses are usually detectable in children by 7 years of age.
• The right and left sinuses each drain through a frontonasal duct into the ethmoidal
infundibulum, which opens into the semilunar hiatus of the middle nasal meatus
• The frontal sinuses are innervated by branches of the supra-orbital nerves(CN
V1

28. • ETHMOIDAL CELLS (sinuses)
• are small invaginations of the mucous membrane of the middle and superior nasal
meatus into the ethmoid bone between the nasal cavity and the orbit
• The ethmoidal cells usually are not visible in plain radiographs before 2 years of age
but are recognizable in CT scans
• The anterior ethmoidal cells drain directly or indirectly into the middle nasal meatus
through the ethmoidal infundibulum.
• The middle ethmoidal cells open directly into the middle meatus and are sometimes
called “bullar cells” because they form the ethmoidal bulla, a swelling on the
superior border of the semilunar hiatus
• The posterior ethmoidal cells open directly into the superior meatus
• The ethmoidal cells are supplied by the anterior and posterior ethmoidal branches of
the nasociliary nerves(CN V1)

29. • SPHENOIDAL SINUSES
• are located in the body of the sphenoid, but they may extend into the wings of this
bone They are unevenly divided and separated by a bony septum.
• Because of this extensive pneumatization (formation of air cells), the body of the
sphenoid is fragile
• Only thin plates of bone separate the sinuses from several important structures: the
optic nerves and optic chiasm, the pituitary gland, the internal carotid arteries, and the
cavernous sinuses.
• The sphenoidal sinuses are derived from a posterior ethmoidal cell that begins to
invade the sphenoid at approximately 2 years of age
• In some people, several posterior ethmoidal cells invade the sphenoid, giving rise to
multiple sphenoidal sinuses that open separately into the sphenoethmoidal recess
• The posterior ethmoidal arteries and the posterior ethmoidal nerves that accompany
the arteries supply the sphenoidal sinuses

30. • MAXILLARY SINUSES
• are the largest of the paranasal sinuses.
• They occupy the bodies of the maxillae and communicate with the middle nasal
meatus
• The apex of the maxillary sinus extends toward and often into the zygomatic bone.
• The base of the maxillary sinus forms the inferior part of the lateral wall of the nasal cavity.
• The roof of the maxillary sinus is formed by the floor of the orbit.
• The floor of the maxillary sinus is formed by the alveolar part of the maxilla.
• The roots of the maxillary teeth, particularly the first two molars, often produce
conical elevations in the floor of the sinus.
• Each maxillary sinus drains by one or more openings, the maxillary ostium(ostia),
into the middle nasal meatus of the nasal cavity by way of the semilunar hiatus.
• The arterial supply: is mainly from superior alveolar branches of the maxillary
artery; however, branches of the descending and greater palatine arteries supply the
floor of the sinus
• Innervation: the anterior, middle, and posterior superior alveolar nerves, which are

31. Rhinitis
• The nasal mucosa becomes swollen and inflamed (rhinitis) during severe
upper respiratory infections and allergic reactions (e.g., hay fever)
• Swelling of the mucosa occurs readily because of its vascularity
• Infections of the nasal cavities may spread to the:
• Anterior cranial fossa through the cribriform plate.
• Nasopharynx and retropharyngeal soft tissues.
• Middle ear through the pharyngotympanic tube(auditory tube), which
connects the tympanic cavity and nasopharynx.
• Para nasal sinuses.
• Lacrimal apparatus and conjunctiva.

32. Epistaxis
• Epistaxis (nosebleed) is relatively common because of the rich blood supply
to the nasal mucosa.
• In most cases, the cause is trauma and the bleeding is from an area in the
anterior third of the nose (Kiesselbach area)
• Epistaxis is also associated with infections and hypertension
• Spurting of blood from the nose results from rupture of arteries.
• Mild epistaxis may also result from nose picking, which tears veins in the
vestibule of the nose.

33. Sinusitis
• Because the paranasal sinuses are continuous with the nasal cavities
through apertures that open into them, infection may spread from the
nasal cavities, producing inflammation and swelling of the mucosa of
the sinuses (sinusitis) and local pain
• Sometimes several sinuses are inflamed (pansinusitis), and the
swelling of the mucosa may block one or more openings of the sinuses
into the nasal cavities.

34. Infection of Ethmoidal Cells
• If nasal drainage is blocked, infections of the ethmoidal cells may break
through the fragile medial wall of the orbit
• Severe infections from this source may cause blindness because some
posterior ethmoidal cells lie close to the optic canal, which gives passage
to the optic nerve and ophthalmic artery
• Spread of infection from these cells could also affect the dural sheath of
the optic nerve, causing optic neuritis.

35. Infection of Maxillary Sinuses
• The maxillary sinuses are the most commonly infected, probably because their ostia
(openings) are commonly small and are located high on their superomedial walls
• When the mucous membrane of the sinus is congested, the maxillary ostia are often
obstructed.
• Because of the high location of the ostia, when the head is erect it is impossible for the
sinuses to drain until they are full. Because the ostia of the right and left sinuses lie on the
medial sides (i.e., are directed toward each other), when lying on one’s side only the upper
sinus (e.g., the right sinus if lying on the left side) drains. A cold or allergy involving both
sinuses can result in nights of rolling from side to side in an attempt to keep the sinuses
drained
• A maxillary sinus can be cannulated and drained by passing a cannula from the naris
through the maxillary ostium into the sinus.

36. Pharynx
Funnel shaped fibromuscular
tube found behind nasal, oral
and laryngeal cavities
Extends from the base of skull to
inferior border of cricoid
cartilage (C6) = 12 cm long
Lies between the bodies of the
vertebrae and the larynx
between C4-C6.
Becomes continuous with the
esophagus at C6
Conducts food and air
The cavity above the inlet of
larynx is wide and always open
The cavity below the inlet of the
larynx is narrow, the anterior &
posterior parts are in contact
except during food passes
36

37. • Boundaries and relation
• Superior – body of sphenoid and basilar part of occipital bone
• Inferior – continues with esophagus
• Posterior – prevertebral fascia
• Anterior – communicate with nasal cavity, oral cavity and larynx
• Lateral – attached to medial pterygoid plate, pterygomandibular raphe, mandible,
tongue, hyoid, thyroid and cricoid cartilage
• Parts: nasal (nasopharynx), oral (oropharynx) and laryngeal
(laryngopharynx)
37

38. • Openings in the pharynx
–Anterior
• Two posterior nasal
openings
• Oropharyngeal isthmus
• Inlet of larynx
–Lateral – openings of the
auditory tube
–Inferiorly – into
esophagus
• Walls of the pharynx
–Composed of (inside
out)
1. Mucus membrane
2. Submucosa
3. Pharyngobasilar fascia
4. Muscles 38

39. It has 3 parts -
Nasopharynx,
Oropharynx &
Laryngopharynx
 Nasopharynx
• Behind nose and above
lower border of soft
palate
• Respiratory function
only
 Oropharynx
Both air and food
 laryngopharynx
For food only
39
Cavity of the pharynx

40. Muscular layer
Inner longitudinal
and outer circular
skeletal muscles
6 paired skeletal
muscles
Three pairs of
circular
(external
muscles):
superior,
middle and
inferior
constrictor
muscles
Constrict walls
of pharynx
during 40

41. • The three muscles overlap each other and form three gaps which allow
entrance of structures to pharynx
• The interval between the superior constrictor and base of the skull: allows
for
• Levator veli palatini
• Auditory tube
• Ascending palatine artery
• The interval between superior and middle constrictor
• Stylopharyngeus
• Cranial nerve IX
• Stylohyoid ligament
• The interval between middle & inferior constrictors covered by thyrohyoid
membrane transmits
• Internal laryngeal nerve
• Superior laryngeal vessels
• Between the inferior constrictor and esophagus
• Inferior laryngeal vessels
• Recurrent laryngeal nerve
41

42. 42

43. 43
• Three pairs of longitudinal
(internal muscles):
1. palatopharyngeus,
2. stylopharyngeus &
3. Salpingophayngeus
• Elevate (shorten and widen)
pharynx and larynx during
swallowing and speaking

44. Innervation of constrictor
muscles
Superior and middle
constrictor muscles are
innervated by the pharyngeal
branches of the vagus nerve
Inferior constrictor muscle
and the cricopharyngeus are
innervated by recurrent
branches of the vagus nerve
The swallowing reflex is
performed by motor fibers
and parasympathetic fibers of
the vagus nerve
The three muscles overlap
each other and form three
gaps which allow entrance
of structures to pharynx
44

45. Internal muscles of the pharynx
 Elevates pharynx during
swallowing
 Stylopharyngeus -CN IX
 Palatopharyngeus – pharyngeal
plexus
 Salpingophayngeus - pharyngeal
plexus
Sensory branches
• nasopharynx - maxillary
nerve (CN V2)
• oropharynx - CN IX
• laryngopharynx - CNX
• Taste from epiglottic area –
internal laryngeal nerve
• Parasympathetic – greater
petrosal nerve
45

46. Larynx
• LARYNX
• It is the complex organ of
voice production (the “voice
box”) composed of nine
cartilages connected by
membranes and ligaments
and containing the vocal
folds(“cords”).
• The larynx is located in the
anterior neck at the level of
the bodies of C3–C6 vertebrae
• Functions
Voice production
Air passage to trachea
Acts as a valve for preventing
swallowed food from entering
the lower respiratory tract
46

47. • Position
At midline of neck from root of
tongue to trachea
In front of laryngopharynx
opposite C3 to C6
Superiorly continuous with
laryngopharynx
Inferiorly continuous with
trachea
5 cm in adult man but slightly
shorter in female & children
47

48. • Structures
9 cartilages joined by
ligaments and membranes
Three unpaired –
1. thyroid,
2. cricoid &
3. epiglottis
Three paired –
1. arytenoids,
2. corniculate &
3. cuneiforms
48

49. Thyroid cartilage
-is the largest laryngeal
cartilages.
• Its superior border lies
opposite the C4 vertebra.
• It form the laryngeal
prominence (Adam's apple•
).
• The cricoid cartilage
• forms a complete ring
around the airway, the only
laryngeal cartilage to do so.
• The epiglottic cartilage
• consisting of elastic
cartilage, gives flexibility to
the epiglottis
49

50. Muscles of larynx
• Extrinsic muscles – move larynx during swallowing
• Infrahyoid muscles – depress hyoid and larynx
• Suprahyoid muscles – elevates hyoid and larynx
• Thyrohyoid – depress hyoid and elevate thyroid cartilage
• Intrinsic muscles – move laryngeal parts
• Alter length and tension of vocal folds and size and shape of rima
glottidis
• Divided based on their action on inlet of larynx
50

51. 1. Muscles closing the inlet of the
larynx
Transverse arytenoid muscle
• unpaired
• attaches to the posterior
aspects of the 2 arytenoid
cartilage
• Its contraction will adduct the
arytenoid cartilages
Oblique arytenoid
• Superficial to transverse
• 2 bundles cross each other,
each arises from the muscular
process of one arytenoid to the
apex of the other arytenoid
Thyro-epiglottic muscle
• Pulls the epiglottis fore ward
and widens the inlet
Lateral crico-arytenoid muscle
• Rotate the arytenoid cartilages
medially
51

52. 2. Abductor of vocal folds
Posterior crico-arytenoid muscle
52
3. Relaxer of vocal folds
Thyro-arytenoid muscle

53. • Tensor of vocal cords
• Cricothyroid muscle
• Its contraction tilts the thyroid
cartilage anteriorly, resulting in
tension of the vocal cords
53

54. Vocal folds
Concerned with production of
sound
Wedge-shaped; apex pointed
medially and base lies against
thyroid lamina
Consists of vocal ligament, conus
conus elasticus, muscle and
mucous membrane
Vocal folds, rima glottidis and
narrow part of larynx together
together are called glottis
Shape of rima glottidis vary
according to position of vocal
folds
Narrow during ordinary
breathing
Wide during forced
breathing
Linear slit during 54

55. Blood supply
Arteries
• Superior laryngeal artery
– branch of superior
thyroid; runs with internal
laryngeal nerve and pierce
thyrohyoid membrane and
supply interior of larynx up
to vocal folds
• Inferior laryngeal artery –
branch of inferior thyroid;
supply mucosa and muscles
below vocal folds
Veins
• Superior laryngeal vein –
drain into superior thyroid
• Inferior laryngeal vein –
drain into inferior thyroid
55

56. • Innervation
Motor
• All intrinsic
muscles are
supplied by
recurrent laryngeal
nerve except
cricothyroid (by
external laryngeal)
Sensory
• Internal laryngeal –
above vocal folds
• Recurrent
laryngeal – below
vocal folds
56

57. Superior laryngeal nerve
• A branch of vagus, divided into 2
terminal branches
• Internal laryngeal nerve – pierces
thyrohyoid membrane and supply
laryngeal mucosa above vocal folds
• External laryngeal nerve –
descends posterior to sternothyroid
and supply inferior constrictor
and cricothyroid
Recurrent laryngeal nerve
• Ascends in a groove between
trachea and esophagus and gives
branches to pharynx, esophagus and
trachea
• Supplies all intrinsic muscles of
larynx except cricothyroid and
mucous membrane below vocal
folds
• Terminal part enters larynx below
inferior constrictor and divide into
anterior and posterior branches
57

58. Clinical correlation
Recurrent laryngeal nerve is
vulnerable to injury during
thyroidectomy resulting in aphonia
or reduction of voice
Damage to internal laryngeal nerve
produces anesthesia of mucosa
superior to vocal folds which break
the reflex arc causing explosive
coughing when foreign body enters
larynx
Damage to external laryngeal
nerve causes weakness of
phonation
Interruption of both recurrent
laryngeal nerves results in vocal
folds phonation is completely lost
58
FIGURE: Laryngeal branches of right vagus nerve (CN X).The nerves of the larynx are the internal and external branches of
the superior laryngeal nerve and the inferior laryngeal nerve from the recurrent laryngeal nerve.
The right recurrent laryngeal nerve passes inferior to the right subclavian artery.

59. 3.TRACHEA
Begins below the larynx
 About 10 cm long and 2.5 cm wide
 Partly in the neck and partly in the
superior mediastinum
 Bifurcates at the level of T4/5 (sternal
angle)
 Lies in the median plane and inferiorly
it is displaced to the right by the aortic
arch

60. Relations
Anteriorly - brachiocephalic
artery & left common
carotid artery
Posteriorly – esophagus
and recurrent laryngeal
nerves
Left – arch of aorta, left
common carotid and left
subclavian arteries, left
recurrent and pleura
Right - vagus, azgos vein
and pleura

61. THE TRACHEAL WALL
Consists of mucosa,
submucosa, and adventitia
 Mucosa -pseudostratified
columnar
Submucosa - a connective
tissue layer
 contains seromucous glands
Adventitia outer connective
tissue layer

62. NEUROVASCULATURE
Blood supply branches- from inferior thyroid artery & bronchial artery
Venous drainage – left brachiocephalic through inferior thyroid vein
Lymphatic – pretracheal and paratracheal lymph nodes
Nerve supply
• Parasympathetic - vagus through recurrent laryngeal nerve;
secretomotor to glands and broncho-constrictors
• Sympathetic trunk – cervical ganglion
• bronchodilator and vasoconstrictors

63. Clinical correlation
• Tracheotomy
surgical incision through anterior
wall of trachea in case of laryngeal
obstruction
done b/n 2nd and 3rd rings
(covered by isthmus) because
supra isthmus is liable to stricture
and infra isthmus is dangerous
due to thyroid vessels
63

64. Thorax
Compiled by Dr. Girmay G. ( anatomist and MD.)

65. Thorax
The thorax (chest) is the
superior part of the trunk
between the neck and
abdomen
The superior thoracic
aperture bordered by
vertebra TI, rib I, and the
manubrium of sternum
The inferior thoracic
aperture bordered by
vertebra T12, rib 12, the
end of rib 11, the costal
margin, and the xiphoid
process of sternum
Anterior view

66. Thoracic skeleton
• The osteocartilaginous
thoracic cage includes the
sternum, 12 pairs of ribs and
costal cartilages, and 12
thoracic vertebrae and
intervertebral discs
• The clavicles and scapulae
form the pectoral (shoulder)
girdle, one side of which is
included here to demonstrate
the relationship between the
thoracic (axial) and upper
limb (appendicular)
skeletons
• The red dotted line indicates
the position of the
diaphragm, which separates
the thoracic and abdominal

67. The functions of the thoracic wall
• The domed shape of the thoracic cage provides remarkable rigidity, given the
light weight of its components, enabling it to:
• Protect vital thoracic and abdominal organs (most air or fluid filled) from external
forces.
• Resist the negative (sub-atmospheric) internal pressures generated by the elastic recoil
of the lungs and inspiratory movements
• Provide attachment for and support the weight of the upper limbs.
• Provide the anchoring attachment (origin) of many of the muscles that move and
maintain the position of the upper limbs relative to the trunk, as well as provide the
attachments for muscles of the abdomen, neck, back, and respiration

68. Thoracic wall
The thoracic wall
consists of
skin,
fascia,
nerves,
vessels,
muscles, and
bones

69. The Bony Thorax (thoracic cage)
Sternum
Composed of Manubrium, Body,
Xiphoid Process
form anterior boundary with
costal cartilages
Ribs (12 pair)
7 pair True Ribs
3 pair False Ribs
2 pair are floating
 Form lateral boundaries
Vertebrae
Thoracic(12)
Forms Posterior boundary of the
cage

70. The Sternum
Manubrium
Has Jugular
notch
Articulats with
#1 & 2
Articulate with
clavicle at
facets
Sternal Angle –
articulate 2nd rib
which is a major
surface landmark
used by clinicians
Body
Articulates
with ribs 2-7
Xiphosternal
joint
Xiphoid process
Cartilage-
calcifies
through time
Partial
attachment of
many muscles

71. FIGURE. Sternum. A. The thin, broad membranous bands of the radiate sternocostal ligaments pass from the costal cartilages
to the anterior and posterior surfaces of the sternum—is shown on the upper right side. B. Observe the thickness of the
superior third of the manubrium between the clavicular notches. C. The relationship of the sternum to the vertebral column is
shown

72. The Ribs
Twelve pairs
Ribs 1-7 attach directly
to sternum by separate
costal cartilages - true
ribs
Ribs 8-10 attach
indirectly to sternum by
attaching to costal
cartilages –false
immediately above
Ribs 11-12 have no
anterior attachments -
floating ribs

73. Rib Anatomy
Typical Ribs
(3rd-9th)
Features of
typical ribs
Head (2
facets)
Neck
Tubercle
Angle
Shaft
Subcostal
Groove
FIGURE. Typical ribs
• A. The 3rd–9th ribs have
common characteristics
• Each rib has a head, neck,
tubercle, and body (shaft).
• B. Cross section of the mid
body of a rib

74. • Atypical Ribs (1st , 2nd , 10th , 11th
& 12th )
1st rib-short, wider, posses
subclavian groove , no angle
1st , 10th, 11th -12th articulate
with only = one vertebra (single
articular facet)
#11, 12
don’t articulate with
transverse processes (not
have tubercle), or anteriorly
at all,
very short neck,
poor/no angle and costal
groove

75. First rib
• broadest and most curved
• flat, has scalene tubercle
• many structures cross it: clinically
important
• subclavian vein and artery
• inferior trunk of brachial plexus
• difficult to palpate because of
clavicle
Second rib
• thinner and less curved
• has tuberosity for serratus anterior
10th rib
• articulates with T10 vertebra only
11th and 12th ribs
• short
• have single facet on their head
• have no neck or tubercle

76. Typical Rib Articulation
Costovertebral joints: are
synovial joint
body has 2 costal facets
(demifacets ) :-
1-Superior costal facet
for rib corresponding to
it.
Inferior costal facet for
rib below it
 Costotransverse joints:
are synovial joints
• Tubercle of Rib 
Transverse Costal Facet
• e.g. Rib #4 articulates
with
• Superior Costal Facet
and Transverse Costal
Facet of T4 &
• Inferior Costal Facet of
T3.

77. Ventral (A)
Attachment to
Sternum
Sternocostal
joint -Via costal
cartilage
Interchondral
joints -occur
between the
costal
cartilages of
adjacent ribs
Costochondral-
b/n the rib and
its costal
cartilage

79. Thoracic Vertebrae
Body= heart shaped
Vertebral arch (neural arch)=around
vertebral foramen: composed of
1-pedicle (joining body to transverse
process)
2-transverse process (lateral projection of
arch)
3-lamina (joining Transverse Process to
Spinous Process )
4- the spinous process (posterior
projection, point inferiorly)
5. Articular process
Transverse Costal Facets :on the
transverse process.
vertebral foramen: circular passage
enclosed in Vertebral arch and
contains spinal cord.

80. Vertebral Column
Humans’ Vertebral Column made of 33
bones
Cervical 7
Thoracic 12
Lumbar 5
Sacrum (5 fused sacral vertebrae)
Coccyx (4 fused coccygeal vertebrae)
Extends from skull to pelvis
Supports body, muscle attachment
Vertebral Canal
• Created by vertebral foramen
• Contains & protects spinal cord
Intervertebral foramina-space b/n pedicles of
adjacent vertebrae
intervertebra
l disk

81. Intervertebral Discs
Is secondary cartilaginous joint b/n
adjacent vertebral bodies
Annulus Fibrosus
Outer collar of concentric
rings
Outer rings = ligamentous
Inner rings = fibrocartilag
Nucleus Pulposus
Inner disc, cushiony pad
Shock Absorber

82. Vertebral Column
• Curvatures
(Following Dorsal Side)
Cervical Region = Concave curve
Thoracic Region = Convex curve
Lumbar Region = Concave curve
Sacrum = Convex curve

83. Abnormal curvature of thoracic vertebrae
Scoliosis
The most common of the abnormal
curves, is a lateral bending of the
vertebral column, usually in the
thoracic region
 It may result from:
congenitally (present at birth)
malformed vertebrae,
chronic sciatica,
paralysis of muscles on one side of the
vertebral column,
poor posture, or one leg being shorter
than the other.
83

84. Kyphosis:
is an increase in the thoracic curve of
the vertebral column
In tuberculosis of the spine, vertebral
bodies may partially collapse,
In the elderly, degeneration of the
intervertebral discs leads to kyphosis.
Kyphosis may also be caused by
rickets and poor posture.
84

85.  It is an increase in the lumbar curve of the
vertebral column
It may result from increased weight
of the abdomen as:
pregnancy
extreme obesity,
poor posture,
rickets,
osteoporosis
tuberculosis of the spine.
85
Lordosis (bent backward):

86. Breasts: external anatomy
Present in both sexes, but they are
functional in females
Anterior to the pectoral muscles of
the thorax
Contains mammary glands;
modified sweat glands that produce
milk to nourish a newborn baby
Base: 2nd to 6th ribs and sternum
to midaxillary line
Slightly below the center of each
breast is a ring of pigmented skin,
the areola, which surrounds the
central conical protruding nipple
Nipple is located at 4th intercostal
space in nulliparous
86

87. Breasts: internal anatomy
Lies in superficial fascia
Between breast and deep fascia
on pectoral muscle is
retromammary space; allows
breast to move freely
each mammary gland consists of
15 to 25 lobes that radiate
around and open at the nipple
The lobes are separated by fat
and fibrous connective tissue
87

88. The Mammary Glands
The interlobar connective tissue
forms suspensory ligaments that
attach the breast to the underlying
muscle fascia and to the overlying
skin
The suspensory ligaments provide
natural support for the breasts
88

89. The Mammary Glands
Within the lobes are smaller units
called lobules which contain
glandular alveoli that produce milk
when lactating
These compound alveolar glands pass
milk into the lactiferous ducts,
which open to the outside at the
nipple
Just deep to the areola, each
lactiferous duct has a dilated region
called a lactiferous sinus
89

90. Arterial supply: internal
thoracic artery, axillary
artery and intercostal
arteries
Venous drainage: axillary,
internal thoracic, lateral
thoracic and intercostal veins
Lymphatic drainage: from
subareolar lymphatic plexus
most lymph drains to axillly
lymph nodes(75%) and some
lymph from medial and
inferior part drains to
parasternal and abdominal
lymph nodes
Innervation: lateral and
anterior cutaneous branches
of 4th to 6th intercostal
nerves
90

92. Clinical correlates
• Breast cancer
Interference of lymphatic drainage by cancer may cause lymphedema, which
results in deviation of nipple and thickening of skin
Prominent skin between dimpled pores may develop due to involvement of
suspensory ligaments
Most common in upper lateral quadrant of the breast
• Congenital anomalies
Polymastia and polythelia – breasts and nipples exceeding two
• Usually rudimentary
• Appear along the line from axilla to groin (embryonic mammary ridge)
92

93. Thoracic wall muscles
• The true muscles of
the thoracic wall are
the
• serratus posterior,
• levatores costarum,
• intercostal,
• subcostal, and
• transversus thoracis
Levator
costarum

94. Thoracic Muscles
External Intercostals
O: Inferior border of rib above
I: Superior border of rib below
Not complete anteriorly (anterior
intercostal membrane replaces at
Costochondral joints)
Fibers run oblique (down and
forward)
Aid in Inspiration (lift ribcage,
increase dimensions)

95. Internal intercostals
Origin - superior border of rib below
Insertion - inferior border of rib above
Occupy intercostal spaces from
sternum to angles of ribs
posteriorly replaced by internal
intercostal membranes
Action - draws ribs together; aids in
respiration

96. 2-the intermediate layer ; consists:-
• Internal Intercostals
O: Superior border of
rib below
I: Inferior border of
rib above
A- aid in expiration
Not complet
posteriorly
(posterior
intercostal
membrane begins
at an angle of rib)
Fibers run at RIGHT
ANGLES to external
intercostals

97. Innermost intercostal
Similar to
internal
intercostal;
deep portions
of them
Separated from
internal
intercostals by
intercostal
nerves and
vessels

98. Subcostal muscles
Variable in size and
shape
Extend from internal
surface of angle of ribs to
internal surface of the rib
below crossing one or
two intercostal spaces

99. Transversus thoracis
Origin - from the back of the
sternum and the xiphoid process
Insertion - onto costochondral
junctions of ribs 3-6
Can bridge more than one
intercostal space

100. Thoracic Muscles
Serratus posterior :includes:-
Serratus posterior superior
 O-Spineous process of C6 ---T2
 I- Rib 2—5 (lateral to angle of
rib)
 A- help in inspiration
Serratus posterior inferior
 O-spineous process of T11---
L2
 I- Rib 9—12 (lateral to angle
of rib)
 A- help in expiration
Levator costarum
 O-tip of transverse process of
C7---T11

101. Neurovascular Bundle of Intercostal Muscles
• VAN =top to bottom(vein, artery, nerve)
in the costal groove
• Intercostal vein
• Intercostal artery
• Intercostal nerve
• Sit in Subcostal Groove
• Between Intermediate and Inner
intercostal layer
V
A
N

102. 12 pairs of thoracic spinal nerves
Leave spinal cord through corresponding intervertebral foramina and divide
into 2 branches
Posterior (dorsal) rami: innervate muscles, bones, joints and skin of the
back
Anterior (ventral) rami: innervate intercostal musculature, periosteum of
the ribs and skin of the thorax (dermatome)
Ventral rami of T1-T11=intercostal nerves
Ventral ramus of T12 = subcostal nerve
Nerves of thoracic wall

103. Enters intercostal space between
pleura and internal intercostal
membrane
run in middle of intercostal space
between internal intercostal
membrane and muscle
near the angle of the rib enter
intercostal groove between internal
intercostal and innermost intercostal
muscles
Give branches to the muscles and
lateral cutaneous branch
Near sternum turns anteriorly and
ends as anterior cutaneous branch
Supply successive segments of
thoracoabdominal wall (dermatome
and myotome)
Intercostal Nerves

104. Intercostal arteries
• Gives collateral branch
• Enters intercostal space at the back
(posterior intercostal artery) and front
(anterior intercostal artery)
• Usually anterior & posterior IC arteries
anastamose in their IC space
• posterior intercostal arteries arise- from
descending thoracic aorta, except the 1st
two (superior IC Artery)which came
from descending branch of
costocervical trunk.
• Anterior intercostal arteries – the upper
6 arise from internal thoracic artery the
lower 3 from musculophrenic branch
• NB: the last two spaces have no anterior
IC artery

106. Intercostal veins
Accompanying arteries and have
same name
Posterior IC vein – drains :
On the right side: lower 8 IC
veins and superior IC (2nd & 3rd
)vein to Azygos vein and the 1st
IC vein to right brachiocephalic
vein
On the left side : lower 8 IC
veins to hemiazygos &
accessory Azygos vein and the
2nd , 3rd and superior IC to
brachiocephalic.

107. 107
Anterior IC vein –drain to
musculophrenic and internal thoracic
vein

109. The pleural cavity and the
LUNG

110. The pleural Cavity and Mediastinum

111. The Pleurae
Double layered serous membrane
lined with mesothelium (simple
squamous epithelium)
1. parietal pleura (outer) – adherent to
body wall
2. visceral pleura (inner) - attached with
lung and its fissures
 The two layers are continuous around
hilum
 A potential space between the two
layers is called pleural cavity
111

112. The parietal pleura
Attached to the costal,
diaphragmatic, cervical and
mediastinal surfaces of thoracic
wall by the endothoracic fascia
Parts of the parietal pleura
Diaphragmatic
Mediastinal
Costal
Cervical (copula)
It also encloses the great vessels
running to the lung root
projects into the root of the
neck as the copula 112

113. The visceral pleura
Covers surfaces and fissures of
lungs
Firmly adherent to lung
Insensitive to pain
Provides a moistened and
lubricated surface for lung
movement
Adhesions with the parietal pleura
may result from infections,
inflammatory reactions and lung
immobility
Visceral and parietal pleurae are
continuous at the root of the lungs,
where pulmonary artery and vein,
113

114. The Pleural cavity
a slit like potential space between the
parietal and visceral pleurae
filled with a thin layer of pleural fluid
secreted by the pleurae, this lubricating
fluid allows the lungs to glide without
friction over the thoracic wall during
breathing movements
Amount of pleural fluid 5-10ml
The fluid also holds the parietal and visceral
pleurae together
114

115. FIGURE: Relationship of
thoracic contents and linings
of thoracic cage.
• A. The apices of the lungs
and cervical pleura extend
into the neck. The left
sternal reflection of
parietal pleura and
anterior border of the left
lung deviate from the
median plane,
circumventing the area
where the heart is, lies
adjacent to the anterior
thoracic wall
• In this “bare area” the
pericardial sac is
accessible for needle
puncture with less risk of
puncturing the pleural
cavity or lung

116. Pleural recesses
Cavity not occupied by the lung
Reserve spaces for lung to expand
Costodiaphragmatic recesses
inferiorly between costal and
diaphragmatic pleura
5cm vertically, extends from 6-10
ribs
first part of pleural cavity to be filled
with effusion
Costomediastinal recesses
anteriorly between costal and
mediastinal pleura
116

117. Figure: B–D. The shapes of the lungs and the larger pleural sacs that surround them during
quiet respiration are demonstrated. The costodiaphragmatic recesses, not occupied by lung, are
where pleural exudate accumulates when the body is erect. The outline of the horizontal fissure
of the right lung clearly parallels the 4th rib. The ribs are identified by number

118. Innervation and blood supply of the pleura
Parietal pleura
Cervical, costal and peripheral diaphragmatic portion - intercostal nerves and
vessels
Central portion of diaphragmatic and mediastinal – phrenic nerve and internal
thoracic & musculophrenic vessels
Sensitive to pain
Lymphatics–intercostal, internal mammary, diaphragmatic & posterior
mediastinal lymph nodes
 Visceral pleura
Sympathetic nerves derived from T4 & T5
insensitive to pain
vasculature and lymphatics are similar to lung
118

119. Clinical correlates
Pneumothorax – presence of air in the pleural cavity
Haemothorax - when blood accumulates
Hydrothorax - when fluid accumulates
Pleurisy – inflammation of the pleura  rough surface  rubbing 
sound
Regions of the pleura not protected by ribs – cupula, right
infrasternal, right and left costovertebral angles
119

120. Pleuricentesis (pleural tab)
120
Aspiration of fluid from the pleural
cavity
Mostly done in the 6th intercostal
space at mid axillary line
the needle should be inserted
through middle part of intercostal
space to avoid injury to neurovascular
bundle

121. The Lungs
 occupy all of the thoracic cavity except the
mediastinum
 Each cone shaped lung is suspended in its own
pleural cavity and connected to the mediastinum
External anatomy
 Spongy in texture and pink in colour in young but
mottled black by carbon particles in adults
121
Has:
• An apex, and A base,
• Three borders (anterior, posterior and inferior)
and
• Three surfaces (costal ,diaphragmatic and

122. Apex -Blunt, lie above anterior end of
first ribs
The base (diaphragmatic surface)
Semilunar and concave
Rests on diaphragm which separates the
right lung from right lobe of liver and left
lung from fundus of stomach
It is found at the level of
the 6th costal cartilage in the mid-
clavicular line
the 8th costal cartilage in the mid-
axillary line
rib 10 dorsally
Due to the position of the liver, the base
of the right lung is broader than that of
the left lung.
122

123. Costal surface: Adjacent to sternum, costal cartilages and ribs

124. 124
Medial surface
 has vertebral and mediastinal parts
 The vertebral part: posterior; round occupying the thoracic gutters
 The mediastinal part: lies anterior to the vertebral column. It contains the hilum of the lung

125. Borders
Inferior
Separates the base from
costal and medial surfaces
Anterior
Thin and short
Right vertical
Left shows wide cardiac
notch
Posterior
Thick and ill defined
Correspond to medial
margins of head of ribs
Extends from 7 cervical
spine to 10 thoracic spine 125

126. The root of the lung
Short broad pedicle which
connects medial surface of
lung with mediastinum
Formed by structures
which leave or enter the
lung at hilum
Lie at level of T5-T7
Contents:
A. Bronchus – posterior
 Left – divide after
entering, only one
 Right - divide before
entering: epiarterial &
hyparterial
126

127. B. Pulmonary artery
 On the left – more anterior
and higher
 On the right – between
eparterial and hyparterial
C. Pulmonary veins – two
in each, superior and
inferior
A. Superior – anterior and
inferior to pulmonary
artery and bronchus
B. Inferior – the most inferior
D. Bronchopulmonary
lymph nodes
127

128. E. Bronchial vessels
A. Bronchial artery - left
two (braches of
descending aorta) &
right one (upper left
bronchial artery/3rd
posterior intercostal)
B. Bronchial veins - right
to azygos and left to
accessory azygos and
hemiazygos
F. Pulmonary plexus –
parasympathetic +
sympathetic
G. Lymphatics of lung
H. Areolar tissue

129. The right lung
The right lung has 3 lobes and 2 fissures
Horizontal fissure
From anterior border of right lung at
4th costal cartilage to meet the oblique
fissure at mid axillary line.
divide the superior from the middle
lobe
Oblique fissure
between middle and inferior lobes
from posterior border 6 cm below the
apex (at third thoracic spine) to the
inferior border 5cm from median
plane
Examination of the superior lobe is
done on the anterior chest wall,
whereas examination of the inferior
lobe is done posteriorly below the
scapula
129

130. The left lung
has a superior and inferior
lobe divided by an oblique
fissure
 large cardiac notch found on
the mediastinal surface
The lingula - an anterior
projection of the superior lobe
below cardiac notch overlies
the anterior aspect of the heart
130

131. 131
Right lung Left lung
Size Larger and heavier (700gm) Small and lighter (600gm)
Length and width Shorter & broader Longer and narrower
Anterior border Straight Cardiac notch & lingula
Lobes and fissures Three lobes & two fissures Two lobes & one fissure
Arterial supply One bronchial artery Two bronchial arteries
Arrangement in the
hilum
medial medial
Differences between right and left lung

132. Bronchopulmonary segments
Right lung
I. Upper
I. Apical
II. Anterior
III. Posterior
II. Middle
I. Medial
II. Lateral
III. Lower
I. Apical
II. Anterior basal
III. Posterior basal
IV. Medial basal
V. Lateral basal
Left lung
I. Upper
I. Apicoposterior
II. Anterior
III. Superior lingular
IV. Inferior lingular
II. Lower
I. Apical
II. Anterior basal
III. Posterior basal
IV. Medial basal
V. Lateral basal
132

134. Trachea and Bronchi
The two main bronchi (primary
bronchi), one to each lung, pass
inferolaterally from the
bifurcation of the trachea to the
lungs at the level of the sternal
angle to the hila of the lungs.
The walls of the trachea and
bronchi are supported by C-
shaped rings of hyaline cartilage.
The right main bronchus is wider,
shorter, and runs more vertically
than the left main bronchus as it passes
directly to the hilum of the lung.
The left main bronchus passes
inferolaterally, inferior to the arch of
the aorta and anterior to the
esophagus and thoracic aorta, to
reach the hilum of the lung.

135. Bronchial Tree
Primary (main) Bronchi
Bifurcation of trachea
Basically the same structure
with trachea
Cartilage plates replace rings
Posterior to pulmonary vessels
Right is wider, vertical, shorter

136. Secondary (lobar) Bronchi
Divisions of each primary
bronchi
Same structure as primary
bronchi
Right lung has 3, Left has 2
Tertiary (segmental) Bronchi
Up to 10 in each lung

137. Bronchioles
further divisions, < 1 mm
diameter
No cartilage
Terminal Bronchioles
further divisions, 0.5 mm
diameter
 Respiratory Zone
Respiratory Bronchioles
Alveolar Ducts (communicate
with alveolar sac
NB: Alveolar Sacs is
• Terminal bunches of Alveoli
• Respiratory exchange chamber

139. Vasculature and Nerves of Lungs and Pleurae
• Each lung has a
large pulmonary
artery supplying
blood to it and
two pulmonary
veins draining
blood from it.

140. Pulmonary artery
are derived from the bifurcated
pulmonary trunk
divide into lobar branches
and then tertiary branches
which have a close relationship
with the tertiary bronchi in the
bronchopulmonary segments
bring deoxygenated blood
which will be oxygenated at the
level of the terminal alveolar
ducts and the alveolar sacs.
Oxygenated blood is returned
to the heart by pulmonary
veins

141. Pulmonary veins
 lower pulmonary veins
from the veins of the
inferior lobe of each lung,
return to the left atrium of
the heart.
The upper right
pulmonary vein comes
from the superior and
middle lobe of the right
lung.
The upper left pulmonary
vein comes from the
superior lobe of the left
lung.
The pulmonary veins also
drain oxygenated blood
supplied to the lungs by the
bronchial arteries.

142. Bronchial Vasculature
The bronchial arteries
• a single right bronchial artery
normally arises from the third
posterior intercostal artery (but
occasionally, it originates from the
upper left bronchial artery);
• two left bronchial arteries arise
directly from the anterior surface of
the thoracic aorta- the superior left
bronchial artery arises at vertebral
level TV, and the inferior one inferior
to the left bronchus.
• The bronchial arteries run on the
posterior surfaces of the bronchi and
supply pulmonary tissues.

143. The bronchial veins
drain into:
• either the pulmonary veins or
the left atrium; and
• In to the azygos vein on the right
or into hemiazygos vein on the
left.
Lymphatic
• are extensive and follow the vascular
tree.
• At the hilus of the lung, they are
filtered by the pulmonary lymph
nodes and then enter the right
lymphatic duct, on the right side.
• On the left side, lymph vessels enter
the thoracic duct.

144. FIGURE: Nerves of lungs and visceral pleura
• The right and left pulmonary plexuses,
anterior and posterior to the roots of the
lungs, receive sympathetic contributions
from the right and left sympathetic trunks
and parasympathetic contributions from the
right and left vagus nerves (CN X).
• After contributing to the posterior pulmonary
plexus, the vagus nerves continue inferiorly
and become part of the esophageal plexus,
often losing their identity and then reforming
as anterior and posterior vagal trunks.
• Branches of the pulmonary plexuses
accompany pulmonary arteries and especially
bronchi to and within the lungs.

145. Nerves
The bronchopulmonary plexus supplies both parasympathetic- and
sympathetic nerves to the bronchial and vascular trees.
Parasympathetic fibers are
secretomotor to glands in the bronchial mucosa,
vasodilators, and
Broncho constrictors
Sympathetic fibers are
vasomotor to arterial system ( vasoconstrictors),
inhibitory to bronchial muscles (bronchodilators) and
inhibitory to the alveolar glands of the bronchial tree—type II
secretory epithelial cells of the alveoli

146. FIGURE: Lymphatic drainage of
lungs.
• The lymphatic vessels originate
from superficial sub-pleural and
deep lymphatic plexuses
• All lymph from the lung leaves
along the root of the lung and
drains to the inferior or superior
tracheobronchial lymph nodes.
• The inferior lobe of both lungs
drains to the centrally placed
inferior tracheobronchial
(carinal) nodes, which primarily
drain to the right side
• The other lobes of each lung
drain primarily to the ipsilateral
superior tracheobronchial lymph
nodes
• From here the lymph traverses a
variable number of paratracheal
nodes and enters the broncho-
mediastinal trunks.

147. Clinical significances of bronchopulmonary segments
• Limit the spread of some diseases within the lung, because infections do not
easily cross the connective tissue partitions between them
• Because only small veins span these partitions, surgeons can neatly remove
segments without cutting any major blood vessel
147