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Chest Wall and Lung Anatomy and Physiology file

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Chest Wall and Lung
Anatomy and
Zeyad S Alharbi, M.D.
Anatomy and Physiology of the Thorax
• Thoracic Skeleton
– 12 Pair of C-shaped Ribs
• Ribs 1-7: Join at sternum with cartilage end-points
• Ribs 8-10: Join sternum with combined cartilage at 7th rib
• Ribs 11-12: No anterior attachment
– Sternum
• Manubrium
– Joins to clavicle and 1st rib
– Jugular Notch
• Body
– Sternal angle (Angle of Louis)
пЃ¶ Junction of the manubrium with the sternal body
пЃ¶ Attachment of 2nd rib
• Xiphoid Process
– Distal portion of sternum
Anatomy and Physiology of the Thorax
• Thoracic Skeleton
– Topographical Thoracic Reference Lines
• Midclavicular line
• Anterior axillary line
• Mid-axillary line
• Posterior axillary line
– Intercostal Space
• Artery, Vein and Nerve on inferior margin of each rib
– Thoracic Inlet
• Superior opening of the thorax
• Curvature of 1st rib with associated structures
– Thoracic Outlet
• Inferior opening of the thorax
• 12th rib and associated structures & Xiphisternal joint
Blood Supply and Innervation
Anterior Chest Wall Deformities
• 1. Pectus excavatum
• 2. Pectus carinatum
• 3. Poland’s syndrome
• 4. Sternal defects
• 5. Miscellaneous
Etiology and Incidence of Pectus Excavatum
• It is reported 1/700 of lives birth
• M:F=3.4:1
• 37% occur in Families with Chest wall
It is a posterior depression of the sternum and
costal cartilage due to over grow of costal
The 1st and 2nd ribs, manubrium are in normal
M-S Abnormalities with Pectus Excavatum
• Scoliosis
• Kyphosis
• Myopathy
• Marfan’s syndrome
• Cerebral palsy
• Prune-belly syndrome
• Tuberous sclerosis
Symptoms of Pectus Excavatum
Decreased exercise tolerance
Dyspnea on exertion, and sternal pain
Palpitations and multiple respiratory tract
infections are reported
• MOST complaint : cosmetic deformity
rather than symptomatology
Pectus Carinatum
( Pigeon Chest )
• It refers to anterior protrusion of the sternum
• It is less common than pectus excavatum
Categories of Pectus Carinatum
• 1. Chondrogladiolar
(I) It is the most common pectus carinatum
(II) It consists of anterior protrusion of
the body of sternum and lower costal
(2) Lateral Pectus Carinatum :
a unilateral protrusion of the costal cartilages and
is usually accompanied by sternal rotation to the
opposite side
(3) Chondromanubrial:
(I) Uncommon
(II) Protrusion of Manubrium,
2nd and 3rd costal cartilages with
relative depression of the body and
Poland’s Syndrome
• It refers to a congenital absence of the
pectoralis major and minor muscles, ribs,
breast abnormality, chest wall depression
and syndactyly, brachydactyly or absence
of phalanges
• It is present in 1/30000
• The etiology is unknown
Thoracic Outlet:
 The space through which the
subclavian artery, vein and
brachial plexus pass to the upper
 Symptoms develop when these
structures are compressed at the
 Boundaries:
First rib, clavicle and Scalene
Scalenus Anterior Muscle
1st Rib
Patient’s arm is elevated
Thoracic Outlet Syndrome “TOS”
{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. }
Cervical Rib:
0.5-1% population (not all
are symptomatic)
пѓ� Neurogenic symptoms
• Ulnar nerve C8-T1 is
usually affected
пѓ� Vascular Symptoms 5%
• Subclavian artery
• Subclavian 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.}
Vascular Symptoms of TOS
Subclavian Artery:
Prolonged compression & trauma
Intimal injury
Stenosis, Thrombosis
Post-stenotic Dilatation or Aneurysm
Distal Micro-embolisation
• {In Unilateral Raynaud’s always
suspect TOS, because usually
Raynaud’s phenomenon is
systemic & will cause bilateral
Surgical Treatment of TOS
Depending on the surgeon’s preference, there are 2 approaches
for the surgery:
• Supraclavicular Approach:
– Scalenectomy
– Excision of 1st rib & fibrous bands
– Repair of subclavian artery if it’s injured and patient has vascular
• Thrombectomy, patch angioplasty
• Excision of aneurysm & bypass graft
{scalenectomy & 1st rib excision are enough in those with
neurological symptoms}
• Transaxillary Approach:
– Excision of 1st rib. This causes the brachial to go down a little relieving
the compression
The Respiratory Muscles
Anatomy and Physiology of the Thorax
appears between the 4th and 7th gestational weeks
• Visceral Pleura
– Cover lungs
• Parietal Pleura
– Lines inside of thoracic cavity.
• Pleural Space
• The relationships of the pleural reflections and
the lobes of the lung to the ribs that at the
midclavicular line, the recess is between rib
spaces 6 and 8, at the midaxillary line between
8 and 10 and at the paravertebral line between
10 and 12.
Lungs – Gross Anatomy
• Paired, cone-shaped organs in thoracic
• Separated by heart and other
mediastinal structures
• Covered by pleura
• Extend from diaphragm inferiorly to
just above clavicles superiorly
• Lies against thoracic cage (pleura,
muscles, ribs) anteriorly, laterally and
Lungs – Gross Anatomy
• Hilum
– Medial �root’ of the lung
– Point at which vessels, airways and
lymphatics enter and exit
• Cardiac Notch
– Lies in medial part of left lung to
accommodate the heart
Lobes and Fissures
Lung – Blood Supply
• Dual Supply
– Bronchial Supply: arises from superior
thoracic aorta or the aortic arch.
• Supply bronchi, airway airway walls and
– Pulmonary Supply
• Pulmonary arteries enter at hila and branch
with airways
• Lymphatic drainage follows vessels
• Parabronchial (peribronchial) lymphatics
and nodes п‚® hilar nodes п‚® mediastinal
nodes п‚® pre- and para-tracheal nodes п‚®
supraclavicular nodes
Anatomy and Physiology of the Thorax
• Mediastinum
– Central space within thoracic cavity
– Boundaries
• Lateral: Lungs
• Inferior: Diaphragm
• Superior: Thoracic inlet
– Structures
Great Vessels
– Vagus
– Phrenic
• Thoracic Duct
Control of Breathing
• Respiratory Center in Reticular
Formation of the Brain Stem
– Medullary Rhythmicity Center
• Controls basic rhythm of respiration
• Inspiratory (predominantly active) and
expiratory (usually inactive in quiet
respiration) neurones
• Drives muscles of respiration
– Pneumotaxic Area
• Inhibits inspiratory area
– Apneustic Area
• Stimulates inspiratory area, prolonging
Regulation of Respiratory Center
• Chemical Regulation
– Most important
– Central and peripheral chemoreceptors
– Most important factor is CO2 (and pH)
•  in arterial CO2 causes  in acidity of
cerebrospinal fluid (CSF)
•  in CSF acidity is detected by pH sensors
in medulla
• Medulla  rate and depth of breathing
Regulation of Respiratory Center
• Cerebral Cortex
– Voluntary regulation of breathing
• Inflation Reflex
– Stretch receptors in walls of bronchi/bronchioles
Respiratory Centers and Reflex Controls
Figure 23.27
• Pulmonary function is affected by lung
resection, extent varies:
– pneumonectomy:
• FEV1: 34~36%↓
• FVC: 36~40%↓
• VO2 max: 20~28%↓
– lobectomy:
• FEV1: 9~17%↓
• FVC: 7~11%↓
• VO2 max: 0~13%↓
Am J of Med (2005) 118, 578–583
Thank You!
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