Thorax & LungsThorax & Lungs

Thoracic CageThoracic Cage

Bony structure in a conical shape, Bony structure in a conical shape, narrower at the top & wider at the bottomnarrower at the top & wider at the bottom

SternumSternum 12 pairs of ribs – 1-7 attach to sternum; 12 pairs of ribs – 1-7 attach to sternum;

8,9,10 attach to costal cartilage; 11 & 12 8,9,10 attach to costal cartilage; 11 & 12 floating floating

12 thoracic vertebrae12 thoracic vertebrae Diaphragm – musculotendinous septum Diaphragm – musculotendinous septum

that separates the thorax from the that separates the thorax from the abdomenabdomen

Anterior LandmarksAnterior Landmarks Suprasternal notchSuprasternal notch Sternum – manibrium, Sternum – manibrium,

body, xiphoid processbody, xiphoid process Manubriosternal angle Manubriosternal angle

– or Angle of Louis. – or Angle of Louis. Continues with second Continues with second rib. Marks where the rib. Marks where the trachea bifurcates into trachea bifurcates into right & left bronchi; right & left bronchi; marks the upper marks the upper border of the heartborder of the heart

Costal angle – right & Costal angle – right & left costal margins left costal margins meet here. Usually less meet here. Usually less than 90 degreesthan 90 degrees

Posterior LandmarksPosterior Landmarks Counting ribs & Counting ribs &

intercostal spaces intercostal spaces more difficult on more difficult on posterior b/c muscle posterior b/c muscle & soft tissue& soft tissue

Vertebra prominens Vertebra prominens – C7, then T1– C7, then T1

Spinous processes – Spinous processes – count down the count down the knobs on the knobs on the vertebraevertebrae

Scapulae end at 7Scapulae end at 7thth or 8or 8thth rib rib

1212thth rib can feel its rib can feel its free tipfree tip

Reference LinesReference Lines

Anterior chest – Anterior chest – midsternal line, midsternal line, midclavicular linemidclavicular line

Posterior chest Posterior chest – vertebral – vertebral line, scapular line, scapular lineline

Lateral chest – anterior Lateral chest – anterior

axillary line, posterior axillary line, posterior

axillary line, midaxillary lineaxillary line, midaxillary line

Mediastinum – middle section of Mediastinum – middle section of thoracic cavity containing thoracic cavity containing esophagus, trachea, heart, & great esophagus, trachea, heart, & great vesselsvessels

Pleural cavity – on either side of the Pleural cavity – on either side of the mediastinum, contains lungsmediastinum, contains lungs

Lung bordersLung borders

Anterior – apex is highest point, 3-Anterior – apex is highest point, 3-4cm above inner 1/3 of clavicles. 4cm above inner 1/3 of clavicles. Base rests on diaphragm at 6Base rests on diaphragm at 6thth rib rib midclavicular linemidclavicular line

Posterior – apex is near C7. Base is Posterior – apex is near C7. Base is at T10at T10

Lung lobesLung lobes Right lung has 3 lobes Right lung has 3 lobes

& is shorter than left & is shorter than left b/c of liver placementb/c of liver placement

Left lung has 2 lobes & Left lung has 2 lobes & is narrower than right is narrower than right b/c heart bulgesb/c heart bulges

Lobes are separated by Lobes are separated by fissuresfissures

Posterior chest is Posterior chest is almost all lower lobe. almost all lower lobe. Upper lobes extend Upper lobes extend down to T3down to T3

PleuraePleurae Thin, slippery serous membrane that Thin, slippery serous membrane that

forms an envelope between lungs & forms an envelope between lungs & chest wallchest wall

Visceral pleura lines outside the lungsVisceral pleura lines outside the lungs Parietal pleura lines inside the chest wallParietal pleura lines inside the chest wall

Inside pleural cavity is pleural fluid that Inside pleural cavity is pleural fluid that lubricates for smooth movement during lubricates for smooth movement during respiration. A vacuum with negative respiration. A vacuum with negative pressure that holds the lungs tight pressure that holds the lungs tight against chest wallagainst chest wall

Trachea & Bronchial Trachea & Bronchial TreeTree Trachea – anterior to esophagus, 10-11 Trachea – anterior to esophagus, 10-11

cm long. Begins at cricoid cartilage in cm long. Begins at cricoid cartilage in neck & bifurcates just below sternal neck & bifurcates just below sternal angle into R & L bronchi. Posteriorly, angle into R & L bronchi. Posteriorly, bifurcates at T4-T5.bifurcates at T4-T5.

Right bronchus is shorter, wider, & Right bronchus is shorter, wider, & more vertical . more vertical .

Bronchi lined with goblet cells that Bronchi lined with goblet cells that secrete mucus that traps particles & secrete mucus that traps particles & lined with cilia that sweeps particles up lined with cilia that sweeps particles up where they can be swallowed. Made up where they can be swallowed. Made up of elastic, connective tissue to expel air of elastic, connective tissue to expel air from lungsfrom lungs

AcinusAcinus Functional Functional

respiratory unit that respiratory unit that consists of consists of bronchioles, alveolar bronchioles, alveolar ducts, alveolar sacs, ducts, alveolar sacs, & alveoli& alveoli

Gaseous exchange Gaseous exchange occurs across the occurs across the respiratory respiratory membrane in the membrane in the alveolialveoli

Mechanics of RespirationMechanics of Respiration

4 major functions4 major functions Supplying oxygen to the body for Supplying oxygen to the body for

energy productionenergy production Removing carbon dioxide as a waste Removing carbon dioxide as a waste

product of energy reactionsproduct of energy reactions Maintaining homeostasis (acid-base Maintaining homeostasis (acid-base

balance) of arterial bloodbalance) of arterial blood Maintaining heat exchange (less Maintaining heat exchange (less

important in humans)important in humans)

O2/CO2 exchange maintains pH O2/CO2 exchange maintains pH balance of the blood within its normal balance of the blood within its normal rangerange

Control of respirations is involuntary, Control of respirations is involuntary, by respiratory center in brain stem by respiratory center in brain stem (pons & medulla). Normal stimulus to (pons & medulla). Normal stimulus to breathe is an increase in carbon breathe is an increase in carbon dioxide in the blood (hypercapnia)dioxide in the blood (hypercapnia)

Changing chest sizeChanging chest size

Air comes in – chest size increasesAir comes in – chest size increases Exhale – chest size decreasesExhale – chest size decreases

Vertically – diameter will move up or Vertically – diameter will move up or downdown

AP diameter – increases or decreases AP diameter – increases or decreases with elevation or depression of ribswith elevation or depression of ribs

Inspiration vs. Expiration Inspiration vs. Expiration InspirationInspiration: :

increasing size of increasing size of thoracic container thoracic container creates a slight creates a slight negative pressure so negative pressure so air rushes in. air rushes in. Diaphragm descends, Diaphragm descends, lengthens vertical lengthens vertical diameter, sternum & diameter, sternum & ribs elevate thus ribs elevate thus increasing increasing anteroposterior anteroposterior diameterdiameter

Expiration Expiration is passive: is passive: diaphragm relaxes, diaphragm relaxes, elastic forces in lungs elastic forces in lungs force the air outforce the air out

Subjective DataSubjective Data

CoughCough SOBSOB Chest pain with breathingChest pain with breathing Hx of respiratory infectionsHx of respiratory infections Hx smokingHx smoking Environmental exposureEnvironmental exposure Self-care behaviors – flu shot, TB Self-care behaviors – flu shot, TB

skin testskin test