Thorax and Lungs

Learning and Understanding Objectives

• Understand:– Surface anatomy and the relationship of the

heart and lungs in the thoracic cavity– Functions of the pleural cavities– Projected placement of the lungs, visceral and

parietal pleura using anatomical landmarks– Functions & deformities of the thoracic cage and

vertebrae– Relationship of nerves, arteries, and veins– Hierarchy of respiratory system in the thorax– Clinical correlations

C7 Spinous Process(Veterbra Prominens)

Vertebral Border of Scapula

12th Rib

Inferior Angle of Scapula

Surface Anatomy of the Posterior Thoracic Wall

Thieme Atlas 4.1A

Thieme Atlas 9.1A

Surface Anatomy of the Anterior Thoracic Wall

Jugular Notch(T2 Vertebral Level)

Clavicle

Sternal Angle(T4 Vertebral Level)

Vertebral Levels of Thoracic Landmarks

(T2)

(T4)

(T9)

Visualize Internal Anatomy when

Looking at a Patient

Figure 21.13a, Marieb

R L

The Thoracic Cage

1.) Protects organs and structures of the thorax

2.) Provides stablesupport for the upper extremity and head

3.) Flexible and can change dimensionsduring ventilation

Thieme Atlas 5.1A

T2

T4

T9

Thieme Atlas 5.3

False Ribs (8-10)Attach to the 7th

costal cartilage

ThreeTypes of Ribs

True Ribs (1-7)Attach directly to

the sternum

Floating Ribs (11-12)No anteriorattachment

Anatomy of a Typical Rib

The Sternum

A blade-like bone with three parts:

ManubriumBody

Xiphoid process

It articulates with the clavicle and ribs 1 -7

Has several important landmarks

Thoracic Vertebrae

1.) Protects organs and structures of the thorax

2.) Protects and housesspinal cord

3.)Support structurefor the thorax and articulates with the ribs

4.) Flexible

Thieme Atlas 5.1C

Thoracic Vertebrae

[ We’ll study these in the lab]

Three Joints of Thoracic Cage

Joints of Thoracic Cage

Marieb, Fig 7.20 a & b

Movements of the Ribs

Thorax Cage Articulates with the Shoulder Girdle

Thieme, Fig 5.5A

Ratio of Anterior-Posterior Diameter : Transverse Diameter

Post.

Ant.

Children (< 6yrs old)

1:1

Adults (> 6yrs old)

Between

1:1.4 - 1:2

Physical Examination and Health Assessment, Table 18-3 Jarvis 2008

Normal

Kyphosis*

Scoliosis*

PectusCarinatum

PectusExcavatum

Barrel Chest*

Thieme 5.26

Anterior Thoracic Wall Muscles

Pectoralis Major

Look for this in Lab

From A.D.A.M. Interactive Anatomy

Pectoralis Minor

From A.D.A.M. Interactive Anatomy

Look for this in Lab

From A.D.A.M. Interactive Anatomy

Serratus Anterior

ExternalIntercostals(Inspiration)

InternalIntercostals

(Forced Expiration)

Muscles of Respiration

Depress ribs

(Contract thoracic cavity)

Elevate ribs

(Expand thoracic cavity)

Action of the Intercostal MusclesAction of the Intercostal Muscles

R LDiaphragm

Major Muscle of Inspiration

-Innervated by thePhrenic Nerve

C3, C4, C5

“C3, 4 & 5 keeps the diaphragm alive”

Muscles of Respiration

Diaphragm: Inferior view

Caval aperture

Psoas major

aorticaperture

esophageal aperture

right crus left crus

Quadratus lumborum

central tendon

Inspiration

Marieb 21.16d

Diaphragm flattensExternal intercostals contract to

raises the ribsVolume of thoracic cavity

increasesDecreases internal gas pressure

Deep inspiration also requires:

Scalenes, pectoralis minor, sternocleidomastoid, and serratus posterior superior all help to elevate the ribs

Erector spinae – extends the back

Expiration

Marieb 21.16d

Diaphragm and Ext. Intercostals relax

Volume of thoracic cavity decreases

Increase in internal gas pressure

Normally PassiveLittle or no muscle contraction

Little or no nerve stimulation of muscles

Forced Expiration Internal intercostals m. contract to

depress ribs

Respiration can be aided by the abdominal wall musclesRespiration can be aided by the abdominal wall muscles

Thieme 6.4B

Arteries of the Posterior Thoracic Wall

Intercostal arteriesIntercostal arteries

Thoracic aortaThoracic aorta

Thieme Fig 5.17 pg 56

Arteries of the Thoracic Wall

Intercostal a.Intercostal a.

2nd Intercostal a. 2nd Intercostal a.

Subclavian a.Subclavian a.

Internal thoracic a.Internal thoracic a.

Internal thoracic a.Internal thoracic a.

Thieme 5.19A

Veins of the Thoracic Wall

Hemiazygos v..Hemiazygos v..

3rd Intercostal v. 3rd Intercostal v.Accessory

Hemiazygos v.Accessory

Hemiazygos v.

Intercostal v..Intercostal v..

Subclavian v.Subclavian v.

Internal thoracic vv.Internal thoracic vv.

Azygos v.Azygos v.

- supply intercostal muscles, abdominal muscles, and

skin of thorax & abdomen

- supply intercostal muscles, abdominal muscles, and

skin of thorax & abdomen

- major pathway for the sympathetic division of the autonomic nervous system

- supply visceral organs.

Nerves of the Posterior Thoracic Wall

Intercostal VAN (Vein, Artery, Nerve)

Thoracic Cavity

3 Compartments of the Thorax

(Heart)

(Great Vessels)

Superior Thoracic Aperture

(Thoracic Outlet )

The apex of the each lung extends above the first rib.

Superior Thoracic Aperture

(Thoracic Outlet )

The apex of the each lung extends above the first rib.

The diaphragm attaches at the inferior border of the ribs, sternum and

the body of vertebra T12..

The diaphragm attaches at the inferior border of the ribs, sternum and

the body of vertebra T12..

Inferior Thoracic Aperture

rib

Visceral Pleura[on the surface of

the lung itself]

Pleural MembranesSecrete serous fluid

– Allows for smooth breathing

Pleural cavity Potential space between the

visceral and parietal pleurae

Surface Tension between parietal and visceral pleura keeps the lungs ‘stuck’ to the thoracic wall during respiration– Necessary for proper

ventilationParietal Pleura

PARIETAL PLEURAPARIETAL PLEURAVISCERAL PLEURAVISCERAL PLEURA

PLEURAL CAVITY(SEROUS FLUID)PLEURAL CAVITY(SEROUS FLUID)

Pleural Membranes

Parietal Pleura:four parts cervical

mediastinal

diaphragmatic

costal

• A Vacuum Seal Makes Ventilation Work

Anterior PosteriorLateral

Midclavicular Midaxillary Paravertebral

Lung 6th rib 8th rib 10th rib

Pleura 8th rib 10th rib 12th ribThieme Atlas, pg 102

At the edges of the thoracic cavity the pleura extend lower

than the lungs to form the Pleural Gutter At the edges of the thoracic cavity the pleura extend lower

than the lungs to form the Pleural Gutter

Pneumothorax – Air in the pleural cavityDamage to visceral or parietal pleura can cause air to leak into the pleural cavity.

Causes: a penetrating wound, infection, cancer, asthma,

Treatment : treat wound, chest tube, thorascopic surgery

Pnemothorax can cause the affected lung to collapse leading to difficulty breathing, cyanosis, and possible shifting the

placement of the heart.

Hemothorax - Blood in the pleural cavity

• difficult ventilation• painful breathing, cyanosis,

tachycardia

• causes – trauma resulting in rupture of pleura

• treatment — remove source of bleeding, drain blood,

thrombolytic agents

• painful breathing, cough, fever, chills

• causes: infection, heart surgery, autoimmune, cancer

• treatment: drain fluid, anti-inflammatory, antibiotics, cancer

treatment

Pleurisy (Pleuritis) – Inflammation of the pleura

Thieme Cl. 5.200A

ThoracentesisThoracentesis

Procedure to remove excess fluid from the pleural space

Procedure to remove excess fluid from the pleural space

Most easily done from the back where the pleural gutter is

deepest and the neurovascular bundle is closer to the inferior

edge of the rib.

Most easily done from the back where the pleural gutter is

deepest and the neurovascular bundle is closer to the inferior

edge of the rib.

Thieme Cl. 5.200A

Chest Tube PlacementChest Tube Placement

To remove air or large amounts of fluid from the pleural space.

Common emergency procedure

Most commonly done along the mid-axillary line between the 4th

and 5th ribs

To remove air or large amounts of fluid from the pleural space.

Common emergency procedure

Most commonly done along the mid-axillary line between the 4th

and 5th ribs

SUP

MIDDLE

INF

SUP

INF

R L

3 Lobes

2 Lobes

Figure 21.8 Marieb

LungsLungs

Lobes Divided into 10 Bronchopulmonary Segments on each Side

Don’t need to name them individually

Lungs

Projections on chest

Inferior is posterior

Superior lobe is mostly anterior

Middle is lateral

Lungs

Projections on chest

Inferior is posterior

Superior lobe is mostly anterior

Middle is lateral

Thieme Atlas fig 8.4

R L

Lungs in situ ( Heart removed)Lungs in situ ( Heart removed)

Hilum—where air and blood enter and leaveHilum—where air and blood enter and leave

Arteries are up high. Bronchi are posterior and near the top. Veins tend to be more anterior and inferior.

Superficial lungs: lateral view

apex

lingula

superior lobe

horizontalfissure

inferior lobe

obliquefissure

middle lobe

right lung

leftlung

Medial Views of the Lungs

groovefor azygos vein

right pulmonary

arteries

bronchii

diaphragmaticrecess

right pulmonary

veins

cardiacimpression

groovefor

esophagus

groovefor aorta

left pulmonary

arteries

left pulmonary

veins

Oral CavityNasal CavityPharynxLarynxTrachea*Lungs*

Respiratory System

Respiratory System—Two Zones

• Conducting zone – Rigid conduits (pipes) for air to reach the sites

of gas exchange– Includes the nose, nasal cavity, pharynx,

trachea, and bronchi.

• Respiratory zone– Site of gas exchange – Consists of terminal bronchioles, alveolar

ducts, and alveoli

The Bronchial Tree One main trunk = Trachea

Two Primary bronchi = One left, one rightSecondary or lobar bronchi = 3 on right, 2 on left

Tertiary to bronchopulmonary segments = 10 each

Trachea

thyroidcartilage

right main bronchus

left main bronchus

trachealbifurcation

Anterior ViewAnterior View

Trachea

membranouswall with trachealglands

carinamucosa

cricoidcartilage

trachealcartilage

Trachea bifurcates into two primary bronchi

Carina at the bifurcation and is very sensitive to irritants – cough

reflex

Trachea bifurcates into two primary bronchi

Carina at the bifurcation and is very sensitive to irritants – cough

reflex

Posterior viewPosterior view

Hyaline Cartilage

Post.

Ant.

Psudostratified columnar Epithelium (ciliated)

Figure 21.7, Marieb

•Has 16-20 C-shaped rings of Hyaline Cartilage•Functions to protect airway

•Prevent collapse of airway during breathing•Pseudostratified columnar epithelium•Ciliated to propel debris to the pharynx

•Has 16-20 C-shaped rings of Hyaline Cartilage•Functions to protect airway

•Prevent collapse of airway during breathing•Pseudostratified columnar epithelium•Ciliated to propel debris to the pharynx

Trachea

Respiratory Segment

Pulmonary Alveoli

Thieme Atlas fig 8.12

TerminalBronchioles

Where the gas exchange takes place between the outside world and the inside world -- blood

Figure 21.8a

Respiratory ZoneRespiratory Zone

300 million Alveoli – external to your body A potential site of invasion—bacteria, smoke,

particles, gases.

Respiratory Membrane

Figure 21.9.c, d

Respiratory Centers in the BrainstemPontine Respiratory Center

Medullary Respiratory Centers

Autonomic Innervationof the Respiratory System

• parasympathetic innervation is from the

vagus (CN X)

• sympathetic innervation is from sympathetic trunk

ganglia

Clinical Correlation - Lungs

Lung Compliance = Stretchability

• The ease with which the lungs can expand, (change in lung volume for a given change in pressure)

• Determined by two main factors– Distensibility of the lung tissue and surrounding thoracic

cage, disease can diminish compliance, but emphysema can

increase compliance. – Surface tension at the air-water interface in the alveoli.

Surfactant reduces the surface tension allowing the alveoli to expand more easily.

COPD (Chronic obstructive pulmonary disease)Hard to breath—Accessory muscles for forced inspiration and expiration. May involve emphysema—Need forced expiration

Figure 21.28

Muscles work more:

External Intercostals and diaphragm.

Accessory muscles:

Sternocleidomastoid,

Scalenes,

Serratus posterior superior

Patient may lean on table to elevate chest

(tripod posture).

Muscles work more:

External Intercostals and diaphragm.

Accessory muscles:

Sternocleidomastoid,

Scalenes,

Serratus posterior superior

Patient may lean on table to elevate chest

(tripod posture).

Pneumonia

• inflammation of aveoli causes build up of fluid in

the lungs

• causes – virus, fungi, bacteria

• treatment — antibiotics, antivirals

Tuberculosis• infectious disease caused

by the bacterium mycobacterium

tuberculosis

• symptoms include fever, night sweats, weight loss,

a racking cough, and splitting headache

• treatment — 12-month course of antibiotics

Emphysema• The walls of the alveoli begin to

breakdown.Alveoli lose their elasticity – increase in

lung compliance

• shortness of breath - difficult to remove air from the lungs – Continual forced

expiration

• causes – typically smoking

• treatment — irreversible, stop smoking, anticholinergics, lung volume reduction

surgery, lung transplant

Lung Cancer

• About 1/3 of all cancer deaths in the u.s.• 90% of all patients were smokers

• Three most common types are: * squamous cell carcinoma (20-40% of cases)

arises in bronchial epithelium * adenocarcinoma (25-35% of cases) originates

in peripheral lung area * small cell carcinoma (20-25% of cases)

lymphocyte-like cells that originate in the primary bronchi and subsequently metastasize

• Treatment — chemotherapy, radiotherapy

surgery (removal of sections of or whole lung• Treatment — chemotherapy, radiotherapy

surgery (removal of sections of or whole lung

Asthma • characterized by dyspnea (trouble breathing), wheezing, and chest

tightness• active inflammation of the airways

precedes bronchospasms (mast cells, allergies)

• airway inflammation is an immune response caused by release of products

that stimulate IgE and recruit inflammatory cells

• airways thickened with inflammatory exudates magnify the effect of

bronchospasms

• treatment – bronchodilators (inhalers, spacers), intubation, steroids, mechanical

ventilation in cases of extreme attack

Respiratory Centers in the BrainstemPontine Respiratory Center

Medullary Respiratory Centers

Autonomic Innervationof the Respiratory System

• parasympathetic innervation is from the

vagus (CN X)

• sympathetic innervation is from sympathetic trunk

ganglia