Anatomy of the respiratory tract

1. Anatomy of the
respiratory tract
Presentation by: Dr. Himanshu Jangid

2. DIVISIONS OF THE
RESPIRATORY SYSTEM
• MOUTH
• NOSE AND NASAL CAVITIES
• PHARYNX
• LARYNX
• TRACHEA AND BRONCHIAL TREE
• LUNGS AND PLEURAL MEMBRANES
• Alveoli

3. MOUTH
• The vestibule: formed by the lips and cheeks without
and by the gums and
teeth within.
• The mouth cavity:bounded by the alveolar arch of
the maxilla and the mandible, and teeth in front, the
hard and soft palate above, the anterior two-thirds
of the tongue and the reflection of its mucosa
forward onto the mandible below, and the
oropharyngeal isthmus behind.

4. MOUTH

5. MOUTH
• The palate:
• The hard palate is made up of the palatine processes of the
maxillae and the horizontal plates of the palatine bones.
• The soft palate hangs like a curtain suspended from the
posterior edge of the hard palate. Its free border bears the
uvula centrally and blends on either side with the pharyngeal
wall.
• Palatine aponeurosis: tough fibrous sheet, the ‘skeleton’ of
the soft palate.

6. MALLALPATI SCORING SYSTEM

7. MOUTH
• The muscles of the soft palate:
• the tensor palati,
• the levator palati,
• palatoglossus,
• palatopharyngeus
• musculus uvulae

8. NOSE
• External nose: is formed by
• The nasal bones.
• The nasal part of the frontal bones.
• The frontal processes of the maxillae.
• A series of cartilages in the lower part.
• A small zone of fibro-fatty tissue that forms the lateral
margin of the nostril (the ala).
• The cartilage of the nasal septum comprises the central
support of this framework.

10. NOSE

11. NOSE

12. NOSE
• The cavity of the nose:
• Subdivided by the nasal septum into two quite separate
compartments.
• Open to the exterior by the nares and into the nasopharynx
by the posterior nasal apertures or choanae.
• Immediately within the nares is a small dilatation, the
vestibule, which is lined in its lower part by stiff, straight hairs.

13. NOSE
• Little’s area:The sphenopalatine branch of the
maxillary artery --------------->
with the septal branch of the superior labial
branch of the facial artery -----------> epistaxis
occurs in some 90% of cases (Little’s area).

14. NASAL CONCHAE
• Superior and middle nasal conchae
– Part of the ethmoid bone
• Inferior nasal conches
– Separate bone
• Project medially from the lateral wall of the
nasal cavity
• Particulate matter
– Deflected to mucus-coated surfaces

15. PARANASAL SINUSES

16. NASAL INTUBATION

17. NASAL INTUBATION CAUTIONS
 Occasionally, the posterior end of the inferior turbinate may be
hypertrophied ---->resistance .
 The delicate mucosa of the nose and the posterior pharyngeal wall
may easily be torn, and force must never be used in this
manoeuvre.
 Cases are on record of nasal tubes being passed through the
mucosa of the posterior pharyngeal wall into the retropharyngeal
space and of serious haemorrhage from injury to the posterior
ethmoidal vessels, which are branches of the internal carotid artery
via the ophthalmic artery and therefore impossible to control by
proximal ligation.

18. MAGILL’S FORCEPS FOR NASAL INTUBATION
• A nasotracheal tube must curve anteriorly as it
passes through the nasopharynx.
• It may be possible to pass a well-curved tube in a
‘blind’ manner, but more flexible tubes will need
assistance if they are to be passed through the vocal
cords.
• Magill’s intubating forceps are commonly used for
this purpose.

19. NOSE
• Nasal obstruction may cause gross discomfort;
thus, packing the nose after surgery may
cause restlessness upon emergence from on
anaesthetic.
• choanal atresia may cause cyanosis in the
newborn.

20. NOSE
• The natural expiratory resistance of the upper
airways is in the order of 1–2 cmH2O and can
be increased subconsciously to provide a
natural form of continuous positive airway
pressure (CPAP).
• Intubation of the trachea decreases this
natural expiratory resistance.

21. PHARYNX
• Nasopharynx
• Oropharynx
• Laryngopharynx

22. PHARYNX

23. PHARYNX
• NASOPHARYNX: Passage way for air only.
• soft palate is elevated during swallowing to block the
nasopharynx and prevent food or saliva from going
up rather than down.
• In the lateral walls of the nasopharynx, paired
auditory/eustachian tubes connect the
nasopharynx to the middle ear.
• Posterior nasopharynx wall also houses a single
pharyngeal tonsil (commonly called the
adenoids).

24. PHARNYX
• OROPHARYNX:
• Arch-like entranceway – fauces
• From the soft palate to the tip of the
epiglottis.
• Two types of tonsils in the oropharynx
– Palatine tonsils – in the lateral walls of the fauces
– Lingual tonsils – covers the posterior surface of
the tongue

25. PHARNYX
• Waldeyer’s ring :The palatine and pharyngeal
tonsils, together with lymph collections on the
posterior part of the tongue and in relation to
the Eustachian orifice.
• Form a more or less continuous ring of
lymphoid tissue around the pharyngeal
entrance,which is termed Waldeyer’s ring.

26. WHAT IS LUDWIG’S ANGINA ?
• Ludwig’s angina :Because of the fascial coat, inflammatory oedema
may spread downwards from infections within the mouth or the tonsils or
from dental sepsis.
• The spread of the oedema is restricted by the pharyngeal fascia and produces
swelling and oedema of the tissues of the larynx and pharynx.
• This may produce difficulty in swallowing and then rapidly progresses to
laryngeal obstruction unless the seriousness of the situation is realized and
surgical drainage of the deep pharyngeal tissues performed.
• Similar complications can occur after operations involving the floor of the
mouth.
• The anaesthetist should always consider the advisability of tracheostomy in
these patients.

27. PHARYNX
• The laryngopharynx: from the tip of the epiglottis to
the lower border of the cricoid at the level of C6.
• Permits passage of both food and air.
• Piriform fossa: The larynx bulges back into the
centre of the laryngopharynx, leaving a recess on
either side.
• Here swallowed sharp foreign bodies such as fish
bones tend to impact.

28. PHARYNX

29. PIRIFORM FOSSA IMPLICATION
• The internal branch of the superior laryngeal nerve passes in
the submucosa of the piriform fossa.
• Local anaesthetic solutions applied to the surface of the
piriform fossa on wool balls held in Krause’s forceps will
produce anaesthesia of the larynx above the vocal cords.
• This is a useful nerve block to supplement oral anaesthesia for
laryngoscopy.

30. PHARYNX
• Muscles of the Pharynx
• Superior, Middle, and Inferior constrictor muscles -
fibers run in a somewhat circular direction.
• Cricopharyngeus muscle- lower part of the inferior
constrictor, which arises from the cricoid cartilage.
• Stylopharyngeus and Salpingopharyngeus muscles -
fibers run in a somewhat longitudinal direction.

32. PHARYNGEAL POUCH

33. PHARYNX
• Nerve Supply:
• All muscle except Stylopharyngeus -Pharyngeal
plexus
• Stylopharyngeus – Glossopharyngeal nerve
• Sensory Nerve Supply of Pharyngeal Mucous
Membrane
• Nasal pharynx: The maxillary nerve (V2)
• Oral pharynx: The glossopharyngeal nerve
• Laryngeal pharynx : The internal laryngeal branch of
the vagus nerve

34. IMPORTANCE OF PHARYNX
• Before larynx its pharynx which makes the
main airway ; hence necessory part to be
managed first.
• Helps in deglutition, protects larynx from
aspiration.

35. CONSCIOUS PATIENT

36. UNCONSCIOUS PATIENT

37. ROLE OF BRAIN LMA

39. LARYNX
• Voice box is a short, somewhat cylindrical airway
ends in the trachea.
• Prevents swallowed materials from entering the
lower respiratory tract.
• Conducts air into the lower respiratory tract.
• Produces sounds.
• Supported by a framework of nine pieces of cartilage
(three individual pieces and three cartilage pairs)
that are held in place by ligaments and muscles.

40. Larynx
• Nine c-rings of cartilage form the framework of the
larynx
• thyroid cartilage – (1) Adam’s apple, hyaline,
anterior attachment of vocal folds, testosterone
increases size after puberty
• cricoid cartilage – (1) ring-shaped, hyaline
• arytenoid cartilages – (2) hyaline, posterior
attachment of vocal folds, hyaline
• cuneiform cartilages - (2) hyaline
• corniculate cartlages - (2) hyaline
epiglottis – (1) elastic cartilage

42. SURFACE MARKINGS OF LARYNX

43. LARYNX
• Muscular walls aid in voice production and the
swallowing reflex
• Glottis – the superior opening of the larynx
• Epiglottis – prevents food and drink from
entering airway when swallowing

44. VOCAL CORDS
• Inferior ligaments are called the vocal folds.
• True vocal cords : produce sound when air passes
between them .
• Superior ligaments are called the vestibular folds.
• False vocal cords : no function in sound production,
protect the vocal folds.
• The tension, length, and position of the vocal folds
determine the quality of the sound.

46. LARYNX
• Cavity of the Larynx
• The cavity of the larynx extends from the inlet to the lower
border of the cricoid cartilage, where it is continuous with the
cavity of the trachea. It is divided into three regions:
• The vestibule, which is situated between the inlet and the
vestibular folds
• The middle region, which is situated between the vestibular
folds above and the vocal folds below
• The lower region, which is situated between the vocal folds
above and the lower border of the cricoid cartilage below

47. LARYNX
• Sinus of the Larynx
• The sinus of the larynx is a small recess on each side
of the larynx situated between the vestibular and
vocal folds.
• It is lined with mucous membrane.
• Saccule of the Larynx
• The saccule of the larynx is a diverticulum of mucous
membrane that ascends from the sinus .
• The mucous secretion lubricates the vocal cords.

48. LARYNX
• Muscles of the Larynx
• Extrinsic Muscles
• move the larynx up and down during swallowing.
• many of these muscles are attached to the hyoid bone, which is attached
to the thyroid cartilage by the thyrohyoid membrane.
• movements of the hyoid bone are accompanied by movements of the
larynx.
• Elevation: The digastric, the stylohyoid, the mylohyoid, the geniohyoid,
the stylopharyngeus, the salpingopharyngeus, and the palatopharyngeus
muscles
• Depression: The sternothyroid, the sternohyoid, and the omohyoid
muscles

49. LARYNX
• Intrinsic Muscles
• Two muscles modify the laryngeal inlet:
• Narrowing the inlet: The oblique arytenoid muscle
• Widening the inlet: The thyroepiglottic muscle
• Five muscles move the vocal cords:
• Tensing the vocal cords: The cricothyroid muscle
• Relaxing the vocal cords: The thyroarytenoid (vocalis) muscle
• Adducting the vocal cords: The lateral cricoarytenoid muscle
• Abducting the vocal cords: The posterior cricoarytenoid
muscle
• Approximates the arytenoid cartilages: The transverse
arytenoid muscle

50. LARYNX
• Nerve Supply of the Larynx
• Sensory Nerves
• Above the vocal cords: The internal laryngeal branch of the
superior laryngeal branch of the vagus.
• Below the level of the vocal cords: The recurrent laryngeal
nerve.
• Motor Nerves
• All the intrinsic muscles of the larynx except the cricothyroid
muscle are supplied by the recurrent laryngeal nerve.
• The cricothyroid muscle is supplied by the external laryngeal
branch of the superior laryngeal branch of the vagus.

51. LARYNX
• Blood Supply of the Larynx
• Upper half of the larynx: The superior
laryngeal branch of the superior thyroid artery
• Lower half of the larynx: The inferior
laryngeal branch of the inferior thyroid artery

56. CRICOTHYROTOMY

57. NERVES OF LARYNX

58. LARYNGOSCOPIC VIEW OF
LARYNX

59. The position of the laryngoscope
in the normal patient

60. The receding chin and poorly-
developed mandible.

61. LARYNGOSCOPY GRADING
SYSTEM
The Cormack and Lehane laryngoscopy
grading system.
Grade 1: all structures visible.
Grade 2: only posterior part of glottis
visible.
Grade 3: only epiglottis seen.
Grade 4: no recognizable structures.

62. TRACHEA
• A flexible tube also called windpipe.
• about 11.25 cm long and 2.5 cm in diameter
• Extends through the mediastinum and lies anterior
to the esophagus and inferior to the larynx.
• Anterior and lateral walls of the trachea supported
by 15 to 20 C-shaped tracheal cartilages.
• Cartilage rings reinforce and provide rigidity to the
tracheal wall to ensure that the trachea remains
open at all times
• Posterior part of tube lined by trachealis muscle

63. TRACHEA
• At the level of the sternal angle, the trachea
bifurcates into two smaller tubes, called the right
and left primary bronchi.
• Each primary bronchus projects laterally toward each
lung.
• The most inferior tracheal cartilage separates the
primary bronchi at their origin and forms an internal
ridge called the carina
• The upper two thirds--> inferior thyroid arteries
• The lower third --->bronchial arteries.

65. TRACHEA
• Unilateral or bilateral enlargement of the
thyroid gland can cause gross displacement or
compression of the trachea.
• Dilatation of the aortic arch (aneurysm) can
compress the trachea.
• Inhaled Foreign Bodies--->Right lung.

66. BRONCHIAL TREE
• Air-conducting passages that originate from the left
and right primary bronchi.
• Progressively branch into narrower tubes before
terminating in terminal bronchioles.
• Incomplete rings of hyaline cartilage support the
walls of the primary bronchi to ensure that they
remain open.
• Right primary bronchus - shorter, wider, and more
vertically oriented.
• Foreign particles are more likely to lodge in the right
primary bronchus.

67. BRONCHIAL TREE
• The primary bronchi ---> hilus of each lung together
with the pulmonary vessels, lymphatic vessels, and
nerves.
• Primary bronchus---> several secondary bronchi .
• Left lung has two secondary bronchi.
• Right lung has three secondary bronchi.
• They further divide into tertiary bronchi.
• Each tertiary bronchus is called a segmental bronchus
because it supplies a part of the lung called a
bronchopulmonary segment.

68. PRIMARY BRONCHI
Right bronchus
Larger
– Leaves the trachea at 25o
angle
– Divides into secondary
bronchi before entering
the lung
– 10 bronchopulmonary
segment
Left bronchus
– Departs the trachea at 45o
angle
– Does not divide into
secondary bronchi until it
reaches the lung
– 8 bronchopulmonary
segment

69. LUNGS
• Cone shaped
• Total volume of 3.5-8.5 liters
• Superior portion is apex
• Inferior portion is base
• Apical portion rises above the clavicle
• Attached by hilum and pulmonary ligament

70. LUNGS
Left Lung
• divided into 2 lobes by oblique fissure
• smaller than the right lung
• cardiac notch accommodates the heart
Right Lung
• divided into 3 lobes by oblique and horizontal
fissure
• located more superiorly in the body due to
liver on right side

71. LUNGS
• Bronchopulmonary segments are as follows:
• Right lung
• Superior lobe: Apical, posterior, anterior
• Middle lobe: Lateral, medial
• Inferior lobe: Superior (apical), medial basal, anterior basal,
lateral basal, posterior basal
• Left lung
• Superior lobe: Apical, posterior, anterior, superior lingular,
inferior lingular
• Inferior lobe: Superior (apical), medial basal, anterior basal,
lateral basal, posterior basal

73. SURFACE ANATOMY OF LUNGS

74. RIGHT LUNG IMPRESSIONS

75. LEFT LUNG IMPRESSIONS

76. LUNGS
• Pulmonary Circulation
– Pulmonary artery
• carry blood to the lungs for oxygenated. These vessels
are central in each bronchopulmonary segment and
branch in a manner similar to the segmental bronchi.
They are considered segmental in nature.
– Pulmonary vein
• at the periphery of each segment and are considered
intersegmental.
• Bronchial artery(branches of the descending aorta): supply
blood to the lungs.
One for right lung and two for left lung.

77. NERVES TO LUNGS
• At the root of each lung is a pulmonary plexus composed of
efferent and afferent autonomic nerve fibers. The plexus is
formed from branches of the sympathetic trunk and receives
parasympathetic fibers from the vagus nerve.
• The sympathetic efferent fibers --> bronchodilatation and
vasoconstriction.
• The parasympathetic efferent fibers--->bronchoconstriction,
vasodilatation, and increased glandular secretion.

78. VENTILATION OF THE LUNGS
• Young children-->ribs are nearly horizontal--->Rely mainly on
the descent of the diaphragm to increase their thoracic
capacity on inspiration--->Referred to as the abdominal type
of respiration.
• After the second year of life, the ribs become more oblique,
and the adult form of respiration is established.
• In the adult a sexual difference exists .
• The female tends to rely mainly on the movements of the ribs
rather than on the descent of the diaphragm on inspiration.
This is referred to as the thoracic type of respiration.
• The male uses both the thoracic and abdominal forms of
respiration, but mainly the abdominal form.

79. MUSCLE ASSISTING VENTILATION
• The scalenes help increase thoracic cavity dimensions
by elevating the first and second ribs during forced
inhalation.
• The ribs elevate upon contraction of the external
intercostals, thereby increasing the transverse
dimensions of the thoracic cavity during inhalation.
• Contraction of the internal intercostals depresses the
ribs, but this only occurs during forced exhalation.
• Normal exhalation requires no active muscular effort.

81. INHALATION AND EXHALATION
Figure 15–6. Actions of the respiratorymuscles. (A)Inhalation:diaphragm contracts
downward;external intercostalmuscles pull ribcage upward and outward; lungs
are expanded. (B) Normal exhalation :diaphragm relaxes upward;rib cage falls down and in as
external intercostal muscles relax; lungsare compressed.

82. PLEURA
• The outer surface of each lung and the adjacent
internal thoracic wall are lined by a serous
membrane called pleura.
• The outer surface of each lung is tightly covered
by the visceral pleura.
• while the internal thoracic walls, the lateral
surfaces of the mediastinum, and the superior
surface of the diaphragm are lined by the
parietal pleura.
• The parietal and visceral pleural layers are
continuous at the hilus of each lung

83. PLEURAL CAVITY
The potential space between the serous
membrane layers is a pleural cavity.
• The pleural membranes produce a thin,
serous pleural fluid that circulates in the
pleural cavity and acts as a lubricant, ensuring
minimal friction during breathing.
• Pleural effusion – pleuritis with too much
fluid

84. PLEURA AND MEDIASTINUM

86. ENDING HERE….
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