The lungs lie either side of
the mediastinum, within the
thoracic cavity. Each lung is
surrounded by a pleural
cavity, which is formed by
the visceral and parietal
Lungs gross anatomy
• Lungs are pair of respiratory organs situated in thoraic cavity
• Right and left lung are separated by the mediastinum
Adults mottled black due to
deposition of carbon particles
Apex – The blunt superior end of the lung. It projects
upwards, above the level of the 1st rib and into the floor
of the neck.
Base – The inferior surface of the lung, which sits on the
Lobes (two or three) – These are separated by fissures
within the lung.
Surfaces (three) – These correspond to the area of the
thorax that they face. They are named costal,
mediastinal and diaphragmatic.
Borders (three) – The edges of the lungs, named the
anterior, inferior and posterior borders.
• The right and left lungs do not have an identical lobular structure.
• The right lung has three lobes; superior, middle and inferior. The lobes are divided from each other by
Runs from the inferior border of the lung in a superoposterior direction, until it meets the
posterior lung border. start from 5tv and end at 6th costochondral junction
Runs horizontally from the sternum, at the level of the 4th rib, to meet the oblique fissure.4th costal
cartilage to meet oblique fissure
The left lung contains superior and inferior lobes, which are separated by a similar oblique fissure.
Surfaces of lungs
• are three lung surfaces, each corresponding to an area of the thorax
The mediastinal surface of the lung faces the lateral aspect of the middle mediastinum.
The lung hilum (where structures enter and leave the lung) is located on this surface
The base of the lung is formed by the diaphragmatic surface. It rests on the dome of the
diaphragm, and has a concave shape. This concavity is deeper in the right lung, due to the
higher position of the right dome overlying the liver.
The costal surface is smooth and convex. It faces the internal surface of the chest wall. It is
related to the costal pleura, which separates it from the ribs and innermost intercostal
The anterior border of the lung is formed by the convergence of the mediastinal and
costal surfaces. On the left lung, the anterior border is marked by a deep notch,
created by the apex of the heart. It is known as the cardiac notch.
The inferior border separates the base of the lung from the costal and mediastinal
The posterior border is smooth and rounded (in contrast to the anterior and inferior
borders, which are sharp). It is formed by the costal and mediastinal surfaces meeting
The lower border of every lung is 2 – rib spaces higher than the lower border of the pleura.
Therefore, it is located along the line, which cuts.
A. 6th rib in the midclavicular line,.
B. 8th rib in the midaxillary line, and.
C. 10th rib at the lateral border of erector spinae and ends 2 cm lateral to the spine of T10
• The anterior border of the left lung has a distinctive notch (the cardiac notch), which
enters laterally behind the 4th and 5th intercostal spaces.
• Its lower end ends at the level of spine of T10 vertebra.
ROOT AND HILUM
The lung root is a collection of
structures that suspends the
lung from the mediastinum.
Each root contains a bronchus,
pulmonary artery, two
pulmonary veins, bronchial
vessels, pulmonary plexus of
nerves and lymphatic vessels.
All these structures enter or
leave the lung via the hilum –
a wedge shaped area on its
• Each Segmental bronchus passes to a structurally and functionally independent
unit of lung lobe called as Broncho Pulmonary Segment.
• These are well defined Anatomic, Functional and surgical units of lungs
16-20 C- shaped hyaline cartilage rings Bifurcates at the level of sternal angle.
Ridge on internal aspect of last cartilage. Point where trachea branches.
Left main bronchus
Longer(5 cm),smaller diameter, more horizontal, makes an angle of 45o with trachea. Gives 2 lobar bronchi
Right main bronchus
Shorter(2.5cm), larger diameter, more vertical( 45o ), more susceptible to aspiration. Gives 3 lobar
Each main or primary bronchus runs into the hilus of lung posterior to pulmonary vessels
Segmental brochi broke into sub segmental bronchus
• Respiratory Bronchiols: 2 or more
branches from each terminal
bronchioles with air sac buds. This is
first level of gas exchange.
• Respiratory bronchioles end in
• Pores of khan & channels of Lambert
are present to connect two alveoli
The lungs are supplied with deoxygenated blood by
the paired pulmonary arteries. Once the blood has
received oxygenation, it leaves the lungs via
four pulmonary veins (two for each lung).
The bronchi, lung roots, visceral pleura and
supporting lung tissues require an extra nutritive
blood supply. This is delivered by the bronchial
arteries, which arise from the descending aorta.
The bronchial veins provide venous drainage. The
right bronchial vein drains into the azygos vein,
whilst the left drains into the accessory hemiazygos
The nerves of the lungs are derived from the pulmonary plexuses.
They feature sympathetic, parasympathetic and visceral afferent
Parasympathetic: Derived from the vagus nerve. They stimulate
secretion from the bronchial glands, contraction of the bronchial
smooth muscle, and vasodilation of the pulmonary vessels.
Sympathetic: Derived from the sympathetic trunks. They
stimulate relaxation of the bronchial smooth muscle, and
vasoconstriction of the pulmonary vessels.
Visceral afferent: Conduct pain impulses to the sensory ganglion
of the vagus nerve
Characteristic Features of BPS
• Largest subdivision of lung lobe.
• Pyramidal in shape with apex towards the root of hilum.
• Each segment is an independent respiratory unit.
• Each segment has its own separate artery [branches of pulmonary artery],segmental
bronchus, autonomic nerves & lymph vessels
The conducting zone of the respiratory system is made up of the following
7. Terminal bronchioles
the trachea commences at the level of the cricoid cartilage in
the neck (C6). It terminates at the level of the angle of Louis (T4/5)
where it bifurcates into right and left main bronchi
the trachea is a rigid fibroelastic structure. Incomplete
rings of hyaline cartilage continuously maintain the patency of
the lumen. The trachea is lined internally with ciliated columnar
behind the trachea lies the oesophagus. The 2nd, 3rd and
4th tracheal rings are crossed anteriorly by the thyroid isthmus
the trachea receives its blood supply from branches of
the inferior thyroid and bronchial arteries
Low resistance pathway for airflow
Warms and moistens air
Phonates (vocalize sounds)
• The respiratory zone is the site of O2 and CO2 exchange with the blood
• The respiratory bronchioles and the alveolar ducts are responsible for 10% of the gas
exchange.The alveoli are responsible for the other 90%.
• The respiratory zone represents the 16th through the 23rd division of the
The pleurae and lungs lie
on either side of the
mediastinum within the
Each lung is enclosed in a serous pleural sac
Serous membrane lined by flattened epithelium
Visceral pleura (Pulmonary pleura)
potential space in between two layers
consists of serous pleural fluid, which lubricate pleural
Adherent to all surfaces including
those in fissures
Except the root or hilum of the lung
Visceral pleura is continuous with
parietal pleura at the hilum of the lung
• Outer layer of the pleura
• Lines the corresponding half of the thoracic wall, mediastinum and diaphragm
• It is divided into four parts
lies over the apex of the lungs
covers the internal surface of the thoracic wall
covers the lateral aspect of the mediastinum
lies on the thoracic surface of the diaphragm
EMPYEMA collection of pus in pleural cavity without air
COMPRESSION OF THE TRACHEA bilateral enlargement of thyroid gland
AORTIC ARCH ANERYSM dilation of aortic arch
TRACHEITIS OR BRONCHITIS give rise to a raw burning sensation felt
deep to the sternum instead of actual pain
INHALED FOREIGN BODIES common in children, tend to enter right
bronchus instead of left because the right bronchus is wider & more direct
continuation of the trachea
BRONCHOSCOPY examination of interior of trachea through bronchoscope
TRACHEOSTOMY cutting the trachea
Which of the following structures separates the
lung into lobes
A section of the lung that receives its own tertiary bronchus is called
A. bronchopulmonary segment
B. pulmonary lobule
C. interpulmonary segment
D. respiratory segment
The ________ circulation picks up oxygen for cellular use and drops off
carbon dioxide for removal from the body.
What does structure R relate to?
A. Groove for azygos vein
B. Oblique fissure
C. Groove for arch of aorta
D. Diaphragmatic surface
The apex of the lungs is covered by:
A. Cervical pleura
B. Diaphragmatic pleura
C. Mediastinal pleura
D. Costal pleura
Which of the following vessels supplies the lungs themselves with
A. Bronchial artery
B. Bronchial vein
C. Pulmonary artery
D. Pulmonary vein
The walls between neighbouring alveoli are known
A. Alveolar septa
B. Alveolar ducts
C. Alveolar epithelia
D. Alveolar sacs
A 'stony dull' sound on percussion is typically suggestive of:
A. Pleural effusion
The lungs and visceral pleura receive
parasympathetic innervation from
A. the vagus nerve
B. cranial nerve IX
C. spinal nerve II
D. the phrenic nerve
The pleura that surrounds the lungs consists of
two layers, the ________.
A. visceral and parietal pleurae.
B. mediastinum and parietal pleurae.
C. visceral and mediastinum pleurae.
D. none of the above
• A 36-year-old man was taken to the emergency department after having been found
lying unresponsive in a local park with an empty whisky bottle nearby. He was
given oxygen by an open face mask during the 15-minute ride in the ambulance. The
paramedic decided to improve the airway by passing a soft nasal tube. On
attempting to pass the well-lubricated tube into the patient’s nose, the paramedic
found it impossible to push it much beyond the nasal vestibule on either side.What
are the common anatomic causes of obstruction of the nasal airway?
The most common cause for difficulty in passing a
nasal tube is a deflected nasal septum. This occurs
more commonly in the male, and is thought to be due
to previous trauma to the septum during the period of
active growth. Nasal spurs and polyps may cause difficulty
and swelling of the mucous membrane secondary
to infection or chemical irritation, and can also cause
blockage. The widest part of the nasal cavity is near
Because of the rapid increase in the size of the tumor,
the following lymph nodes were examined for metastases:
A. Superficial inguinal nodes
B. Anterior axillary nodes
C. Posterior axillary nodes
D. External iliac nodes
E. Deep cervical nodes
ESSIENTIALS OF ANATOMY AND PHYSIOLOGY BY STEPHENS
ROSS AND WILSON ANATOMY AND PHYSIOLOGY
LASTs ANATOMY BY R.M.H MEMINN