Chest Wall and Chest Wall and LungLung

Anatomy and Anatomy and PhysiologyPhysiology

Zeyad S Alharbi, M.D.Zeyad S Alharbi, M.D.

Anatomy and Physiology of the Anatomy and Physiology of the ThoraxThorax

• Thoracic SkeletonThoracic Skeleton– 12 Pair of C-shaped Ribs12 Pair of C-shaped Ribs

• Ribs 1-7: Join at sternum with cartilage end-pointsRibs 1-7: Join at sternum with cartilage end-points• Ribs 8-10: Join sternum with combined cartilage at 7Ribs 8-10: Join sternum with combined cartilage at 7thth rib rib• Ribs 11-12: No anterior attachmentRibs 11-12: No anterior attachment

– SternumSternum• ManubriumManubrium

– Joins to clavicle and 1Joins to clavicle and 1stst rib rib– Jugular NotchJugular Notch

• BodyBody– Sternal angle (Angle of Louis)Sternal angle (Angle of Louis)

Junction of the manubrium with the sternal bodyJunction of the manubrium with the sternal body Attachment of 2Attachment of 2ndnd rib rib

• Xiphoid ProcessXiphoid Process– Distal portion of sternumDistal portion of sternum

Anatomy and Physiology of the Anatomy and Physiology of the ThoraxThorax

• Thoracic SkeletonThoracic Skeleton– Topographical Thoracic Reference LinesTopographical Thoracic Reference Lines

• Midclavicular lineMidclavicular line• Anterior axillary lineAnterior axillary line• Mid-axillary lineMid-axillary line• Posterior axillary linePosterior axillary line

– Intercostal SpaceIntercostal Space• Artery, Vein and Nerve on inferior margin of each ribArtery, Vein and Nerve on inferior margin of each rib

– Thoracic InletThoracic Inlet• Superior opening of the thoraxSuperior opening of the thorax• Curvature of 1Curvature of 1stst rib with associated structures rib with associated structures

– Thoracic OutletThoracic Outlet• Inferior opening of the thoraxInferior opening of the thorax• 1212thth rib and associated structures & Xiphisternal joint rib and associated structures & Xiphisternal joint

Blood Supply and Blood Supply and InnervationInnervation

Anterior Chest Wall Anterior Chest Wall DeformitiesDeformities

• 1. Pectus excavatum1. Pectus excavatum

• 2. Pectus carinatum2. Pectus carinatum

• 3. Poland’s syndrome3. Poland’s syndrome

• 4. Sternal defects 4. Sternal defects

• 5. Miscellaneous 5. Miscellaneous

Etiology and Incidence of Pectus Etiology and Incidence of Pectus Excavatum Excavatum

• It is reported 1/700 of lives birth It is reported 1/700 of lives birth • M:F=3.4:1M:F=3.4:1• 37% occur in Families with Chest wall 37% occur in Families with Chest wall

deformitiesdeformities• It is a posterior depression of the sternum It is a posterior depression of the sternum

and costal cartilage due to over grow of and costal cartilage due to over grow of costal cartilagecostal cartilage

• The 1The 1stst and 2 and 2ndnd ribs, manubrium are in ribs, manubrium are in normal positionnormal position

M-S Abnormalities with Pectus M-S Abnormalities with Pectus Excavatum Excavatum

• ScoliosisScoliosis

• KyphosisKyphosis

• MyopathyMyopathy

• Marfan’s syndromeMarfan’s syndrome

• Cerebral palsyCerebral palsy

• Prune-belly syndromePrune-belly syndrome

• Tuberous sclerosis Tuberous sclerosis

Symptoms of Pectus Symptoms of Pectus ExcavatumExcavatum• Decreased exercise toleranceDecreased exercise tolerance

• FatigabilityFatigability

• Dyspnea on exertion, and sternal painDyspnea on exertion, and sternal pain

• Palpitations and multiple respiratory Palpitations and multiple respiratory tract infections are reported tract infections are reported

• MOST complaint : cosmetic deformity MOST complaint : cosmetic deformity rather than symptomatology rather than symptomatology

Pectus CarinatumPectus Carinatum( Pigeon Chest ) ( Pigeon Chest )

• It refers to anterior protrusion of the It refers to anterior protrusion of the sternumsternum

• It is less common than pectus excavatumIt is less common than pectus excavatum

Categories of Pectus Categories of Pectus CarinatumCarinatum

• 1. Chondrogladiolar1. Chondrogladiolar

(I) It is the most common pectus (I) It is the most common pectus carinatumcarinatum

(II) It consists of anterior protrusion of (II) It consists of anterior protrusion of the body of sternum and lower costal the body of sternum and lower costal cartilages cartilages

(2) Lateral Pectus Carinatum : (2) Lateral Pectus Carinatum : a unilateral protrusion of the costal cartilages and is a unilateral protrusion of the costal cartilages and is

usually accompanied by sternal rotation to the usually accompanied by sternal rotation to the opposite sideopposite side

(3) Chondromanubrial:(3) Chondromanubrial: (I) Uncommon(I) Uncommon (II) Protrusion of Manubrium, (II) Protrusion of Manubrium, 22ndnd and 3 and 3rdrd costal cartilages with costal cartilages with relative depression of the body and relative depression of the body and

sternum sternum

Poland’s SyndromePoland’s Syndrome18411841

• It refers to a congenital absence of It refers to a congenital absence of the pectoralis major and minor the pectoralis major and minor muscles, ribs, breast abnormality, muscles, ribs, breast abnormality, chest wall depression and chest wall depression and syndactyly, brachydactyly or syndactyly, brachydactyly or absence of phalanges absence of phalanges

• It is present in 1/30000It is present in 1/30000

• The etiology is unknownThe etiology is unknown

Thoracic Outlet:Thoracic Outlet: The space through which the The space through which the

subclavian artery, vein and subclavian artery, vein and brachial plexus pass to the brachial plexus pass to the upper limbupper limb

Symptoms develop when these Symptoms develop when these structures are compressed at the structures are compressed at the outletoutlet

Boundaries:Boundaries: First rib, clavicle and Scalene First rib, clavicle and Scalene

musclesmusclesClavicle

1st Rib

Scalenus Anterior Muscle

Patient’s arm is elevated

Thoracic Outlet Syndrome Thoracic Outlet Syndrome “TOS”“TOS”

Cervical Rib:Cervical Rib:0.5-1% population 0.5-1% population (not (not all are symptomatic)all are symptomatic)

Neurogenic symptoms Neurogenic symptoms 95%95%• Ulnar nerve C8-T1 Ulnar nerve C8-T1 is is

usually affectedusually affected

Vascular Symptoms Vascular Symptoms 5% 5% • Subclavian arterySubclavian artery• Subclavian veinSubclavian vein

{cervical rib between the transverse process of C7 & the 1st rib. You can see the cervical rib in the other side elevating the brachial plexus.}

{Definition of cervical rib: an accessory rib which is not normally present. If present it may cause compression of important structures in the thoracic outlet. }

Vascular Symptoms of TOSVascular Symptoms of TOSSubclavian Artery:Subclavian Artery:

Prolonged compression & traumaProlonged compression & trauma

Intimal injuryIntimal injury

Stenosis, ThrombosisStenosis, Thrombosis

Post-stenotic Dilatation or Post-stenotic Dilatation or AneurysmAneurysm

Distal Micro-embolisation Distal Micro-embolisation

BandCervical Rib

• {In Unilateral Raynaud’s {In Unilateral Raynaud’s always suspect TOS, because always suspect TOS, because usually Raynaud’s usually Raynaud’s phenomenon is systemic & phenomenon is systemic & will cause bilateral symptoms}will cause bilateral symptoms}

Depending on the surgeon’s preference, there are 2 approachesDepending on the surgeon’s preference, there are 2 approaches for the surgery:for the surgery:• Supraclavicular Approach:Supraclavicular Approach:

– ScalenectomyScalenectomy– Excision of 1Excision of 1stst rib & fibrous bands rib & fibrous bands– Repair of subclavian artery if it’s injured and patient has Repair of subclavian artery if it’s injured and patient has

vascular problems:vascular problems:• Thrombectomy, patch angioplastyThrombectomy, patch angioplasty• Excision of aneurysm & bypass graft Excision of aneurysm & bypass graft

{{scalenectomy & 1scalenectomy & 1stst rib excision are enough in those with rib excision are enough in those with neurological symptoms}neurological symptoms}

• Transaxillary Approach: Transaxillary Approach: – Excision of 1Excision of 1stst rib. This causes the brachial to go down a little rib. This causes the brachial to go down a little

relieving the compressionrelieving the compression

Surgical Treatment of TOSSurgical Treatment of TOS

The Respiratory MusclesThe Respiratory Muscles

Anatomy and Physiology of the Anatomy and Physiology of the ThoraxThorax

Pleura: Pleura: appears between the 4th and 7th gestational weeksappears between the 4th and 7th gestational weeks

•Visceral PleuraVisceral Pleura– Cover lungsCover lungs

•Parietal PleuraParietal Pleura– Lines inside of thoracic cavity.Lines inside of thoracic cavity.

•Pleural SpacePleural Space

• The relationships of the pleural reflections The relationships of the pleural reflections and the lobes of the lung to the ribs that at and the lobes of the lung to the ribs that at the midclavicular line, the recess is the midclavicular line, the recess is between rib spaces 6 and 8, at the between rib spaces 6 and 8, at the midaxillary line between 8 and 10 and at midaxillary line between 8 and 10 and at the paravertebral line between 10 and 12. the paravertebral line between 10 and 12.

Lungs – Gross AnatomyLungs – Gross Anatomy• Paired, cone-shaped organs in Paired, cone-shaped organs in

thoracic cavitythoracic cavity• Separated by heart and other Separated by heart and other

mediastinal structuresmediastinal structures• Covered by pleura Covered by pleura • Extend from diaphragm inferiorly Extend from diaphragm inferiorly

to just above clavicles superiorlyto just above clavicles superiorly• Lies against thoracic cage (pleura, Lies against thoracic cage (pleura,

muscles, ribs) anteriorly, laterally muscles, ribs) anteriorly, laterally and posteriorlyand posteriorly

Lungs – Gross AnatomyLungs – Gross Anatomy

• HilumHilum– Medial ‘root’ of the lungMedial ‘root’ of the lung– Point at which vessels, airways and Point at which vessels, airways and

lymphatics enter and exitlymphatics enter and exit

• Cardiac NotchCardiac Notch– Lies in medial part of left lung to Lies in medial part of left lung to

accommodate the heartaccommodate the heart

Lobes and FissuresLobes and Fissures

Lung – Blood SupplyLung – Blood Supply

• Dual SupplyDual Supply– Bronchial Supply: arises from Bronchial Supply: arises from

superior thoracic aorta or the aortic superior thoracic aorta or the aortic arch.arch.•Supply bronchi, airway airway walls and Supply bronchi, airway airway walls and

pleurapleura

– Pulmonary SupplyPulmonary Supply•Pulmonary arteries enter at hila and Pulmonary arteries enter at hila and

branch with airwaysbranch with airways

LymphaticsLymphatics

• Lymphatic drainage follows vesselsLymphatic drainage follows vessels

• Parabronchial (peribronchial) Parabronchial (peribronchial) lymphatics and nodes lymphatics and nodes hilar nodes hilar nodes mediastinal nodes mediastinal nodes pre- and pre- and para-tracheal nodes para-tracheal nodes supraclavicular nodessupraclavicular nodes

Anatomy and Physiology of the ThoraxAnatomy and Physiology of the Thorax

• MediastinumMediastinum– Central space within thoracic cavityCentral space within thoracic cavity– BoundariesBoundaries

• Lateral: LungsLateral: Lungs• Inferior: DiaphragmInferior: Diaphragm• Superior: Thoracic inletSuperior: Thoracic inlet

– StructuresStructures• HeartHeart• Great VesselsGreat Vessels• EsophagusEsophagus• TracheaTrachea• NervesNerves

– VagusVagus– PhrenicPhrenic

• Thoracic DuctThoracic Duct

Control of BreathingControl of Breathing

• Respiratory Center Respiratory Center in Reticular in Reticular Formation of the Brain StemFormation of the Brain Stem– Medullary Rhythmicity CenterMedullary Rhythmicity Center

•Controls basic rhythm of respirationControls basic rhythm of respiration• Inspiratory (predominantly active) and Inspiratory (predominantly active) and

expiratory (usually inactive in quiet expiratory (usually inactive in quiet respiration) neuronesrespiration) neurones

•Drives muscles of respirationDrives muscles of respiration

– Pneumotaxic AreaPneumotaxic Area• Inhibits inspiratory areaInhibits inspiratory area

– Apneustic AreaApneustic Area•Stimulates inspiratory area, prolonging Stimulates inspiratory area, prolonging

inspirationinspiration

Regulation of Respiratory Regulation of Respiratory CenterCenter

• Chemical RegulationChemical Regulation– Most importantMost important– Central and peripheral chemoreceptorsCentral and peripheral chemoreceptors

– Most important factor is COMost important factor is CO2 2 (and pH)(and pH) in arterial COin arterial CO2 2 causes causes in acidity of in acidity of

cerebrospinal fluid (CSF)cerebrospinal fluid (CSF) in CSF acidity is detected by pH in CSF acidity is detected by pH

sensors in medullasensors in medulla

•Medulla Medulla rate and depth of breathing rate and depth of breathing

Regulation of Respiratory Regulation of Respiratory CenterCenter

• Cerebral CortexCerebral Cortex– Voluntary regulation of breathingVoluntary regulation of breathing

• Inflation ReflexInflation Reflex– Stretch receptors in walls of Stretch receptors in walls of

bronchi/bronchiolesbronchi/bronchioles

Figure 23.27

Respiratory Centers and Reflex Respiratory Centers and Reflex ControlsControls

• Pulmonary function is affected by lung Pulmonary function is affected by lung resection, extent varies:resection, extent varies:– pneumonectomy:pneumonectomy:

• FEVFEV11: 34~36%↓: 34~36%↓

• FVC: 36~40%↓FVC: 36~40%↓

• VOVO22 max: 20~28%↓ max: 20~28%↓

– lobectomy:lobectomy:• FEVFEV11: 9~17%↓: 9~17%↓

• FVC: 7~11%↓FVC: 7~11%↓

• VOVO22 max: 0~13%↓ max: 0~13%↓

Am J of Med (2005) 118, 578–583Am J of Med (2005) 118, 578–583

Thank You!Thank You!