Thorax Flashcards
What all is in the thorax
Heart
Lungs
THymus
Trachea
Eophagus
Nerves
Vessels
Parietal layer
Covers inner wall of cavity
Visceral layer
Covers surface of organs
Functions of thoracic wall
Protect thoracic and abdominal organs
Resists negative pressure from elastic recoil of lung
Attachment and support to upper limbs, neck, abdomen, back, and respiration muscles
How many ribs do we have
12 pairs
Ribs 1-10
Articulate with costal cartilage
Sternocostal joints
First. seven ribs connect to sternum with costal cartilage
Ribs 8-10
Connect to costal cartilage with rib above them
Floating ribs
11 and 12
Atypical ribs
1 (only articulates with T1)
2
11 and 12 (floating)
Superior thoracic apeture
Circle made by T1, rib 1, and manubrium
Trachea, esophagus vessels, nerves, and pleural cavities pass through
Diaphragm
Primary muscle of aspiration
Right side is higher because of liver.
costophrenic angle
What level does inferior vena cava start
T8
What level does esophagus start
T10
What level does decending aorta start
T12
At what level is the nipple
T4
Parts of sternum
Manubrium
Body
Xiphoid process (doesn’t ossify until 40 y/o)
Sternal angle
Where manubrium meets sternal body.
Where Rib 2 meets sternum
Deltoid
Abducts upper extremity after 15º
Axillary nerve
Pectoralis minor
Protracts scapula
Medial pectoral nerve
Pectoralis major
Adduction, medial rotation, and fexion of humerus at shoulder joint.
Medial and laterla pectoral nerves
Serratus anterior
Scapular protraction, scapular rotation, keeps scapula opposed to thoracic wall
Long thoracic nerve
External oblique
Compress abdominal contents, Bilateral trunk flexion, Ipsilateral lateral flexion, Unilateral rotation to the contralateral side
Anterior Rami of T7-T12
Subclavius
Pulls clavicle medially to stabilize sternoclavicular joint.
Nerve to subclavius from subclavian nerve (C5-C6)
Transversus thoracis
Weak expiratory function and may also provide proprioceptive info.
Intercostal nerves
Endothoracic fascia
Deep to intercostal spaces, muscles, and ribs.
Separates structures from underlying pleura
Superficial to parietal pleura
Intercostal mscles
Three flat muscles (external, internal, and innermost) between the ribs
External intercostal muscle
Muscle fibers do not extend to sternum (replaced by external intercostal membrane to sternum).
Elevates ribs.
innervated by intercostal nerves
Fibers run inferoanteriorly
Internal intercostal muscle
Muscles extend to sternum and posteriorly to angles of ribs (replaced by internal intercostal membranes to vertebral column)
Depresses ribs
Innervated by intercostal nerves.
Fibers run inferoposteriorly
Innermost intercostal
Separated from internal intercostals by intercostal nerves and vessels.
Occupy deep lateral parts of internal thoracic wall
Acts with internal intercostal during expiration.
Innervated by interocostal nerves
What order are the vessels in in the intercostal space superior to inferior
Vein
Attery
Nerve, nerve not protected by the grove so in most danger when upper innercostal space penetrated
Where does first posterior intercostal veins drain
Right and left brachiocephalic veins
Where do all posterior intercostal veins other than the first drain
Azygos system of veins and then into vena cava
Where do anterior intercostal veins drain
Internal mammary/thoracic veins
Where do the first and second posterior intercostal arteries branch from
Subclavian artery
Where do the 3-11 posterior intercostal arteries and subcostal arteries branch from
Subcostal arteries from thoracic aorta
Where do the 1-6 anterior intercostal arteries come from
Internal thoracic/mammary artery
Where do the 7-12 anterior intercostal arteries come from
Musculophrenic arteries
Internal thoracic/mammary artery termination
Terminates in 6th intercostal space into superior epigastric and musculophrenic arteries
Intercostal nerve pathway
3-6 Initially within endothoracic fascia between the parietal pleura and internal intercostal membrane.
Near angles of ribs pass between internal intercostal and innermost intercostal muscles.
Anterior to axillary line pass between the internal intrcostal muscles and endothoracic fascia and continue i costal grooves
T12 is inferior to 12th rib (subcostal nerve)
What dermatome goes across belly button
T10
Intercostal nerves
Provide motor innervation to intercostal muscles
Sensory innervation to the parietal pleura and skin
Anterior cutaneous branches of intercostal nerves
Terminal branches at parasternal line supply skin and anterior aspect of thorax and abdomen (medial and lateral branch)
When to do intercostal nerve block and where to do it
Rib fracture and postop thoractomy pain
Posterior to midaxillary line at costal angle inferior to rib between internal intercostal and innermost intercostal
Chest tube placement
Superior to rib
4th or 5th intercostal space.
usually between anterior and midaxillary line
Structures at sternal angle
Rib2
Aorta
Tracheal bifurcation
Pulmonary trunk
Ligamentum arteriosum
Azygos vein
Nerves
Thoracid duct
Superior vena cava
Ligamentum arteriosum
Remnant of fetal ductus arteriosus.
Shunts blood from pulmonary circulatoin to systemic circulation comes from ductus arteriosus closing several hours after birth due to falling prostaglandin
What does the azygos vein drain into
Superior vena cava
What level does the thoracid duct cross over at
TTP (transthoracic plane)
Azygos vein
No valves
Right of midline
Thoracic duct
Major lymphatic vessel
Left venous angle (junction of left subclavian and internal jugular.
Lies on vertebral bodies between azygos and esophagus
Travels from posterior mediastinum to superior mediatinum adn empties into left internal jugular vein and left subclavian vein junction
What all drains into thoracic duct
Entire left side and everything below the thorax
What all drains into right lymphatic duct
Right arm, Right side of head, right chest
Thymus
Immediately posterior to sternum.
Early development of immune system
Internal jugular vein
Drains blood from right brain and head
Subclavian vein
Drains blood from right upper limb
Brachiocephalic vein
Drains blood from right brain head and upper limb
RIPE
Rotation, inspiration, projection, exposure.
What to worry about in chest radiograph
What strutures are posterior to heart
Descending aorta
Azygos system of veins
Thoracic duct
Esophagus and nerve plexus
Sympathetics
Cisterna chyli
Where thoracid ducts begins in the abdomen
Chylothorax
Rare conditon where lymphatic fluid leaks into the space between lungs and chest wall
Causes chest pain and diff breathing
Where is the superior border of the heart
Sternal angle (T4/T5)
Where is the inferior border of the heart
xiphosternal joint (T8/T9)
Apex of the heart
Inferior lateral part of left ventricle
Midclavicular line in left intercostal space
Where to listen for mitral valve
Apex
Posterior heart
Mostly left atrium
Some right atrium
Contacts esophagus
T6-T9
Pulmonary veins (LA)
Superior and inferior vena cava (RA)
Antterior (sternocostal) surface of heart
Formed by right ventricle
Diaphragmatic (inferior) surface of heart
Formed by left and right ventricles
attaches to central tendon of diaphragm
Right pulmonary surface of heart
Formed by right atrium
Adjacent to right middle lobe of lung
Left pulmonary surface
Formed by left ventricle
Creates cardiac impression on left upper lobe of lung
Layers of pericardium
Superficial is fibrous
Deep is serous (made of parietal and visceral layers)
Fibrous pericardium
Most superfical layer of pericardium
Tough and inelastic
Attaches to great vessels superiorly
Attaches to diaphragm inferiorly at central tendon
Phrenic nerves
Phrenic nerves
From anterior rami C3,C4,C5
Pass through and innervate fibrous pericardium
Pericardiacophrenic vessels
Supply the fibrous pericardium
Branch of internal thoracic artery
Parietal pericardium
Lines internal surface of fibrous pericardium
Can’t be separated from fibrous
Visceral pericardium
Directly covers heart (innermost layer)
Serous fluid
Between serous layers of pericardium (parietal and visceral)
Pericardial sack
Protects the heart
Prevents cardiac distension (overfilling)
Produces lubricating fluid
Made of fibrous, parietal, and visceral layers
Pericardial effusion
Excess fluid build up in pericardial sack (between parietal and visceral layers)
Inability to expand due to fibrous pericardium
Can cause compression of the heart (Cardiac Tamponade)
DO pericardioscentesis to fix (subxiphoid)
Untreated will lead to HF
Transvers pericardial sinus
Separates aorta and pulmonary artery from SVC
Oblique pericardial sinus
Formed by the reflection of pulmonary veins on heart
Layers of heart
Epicardium
Myocardium
Endocardium
Epicardium
Outer layer of heart
Visceral layer of pericardium
Fat and coronary vessels are deep to epicardium
Myocardium
Middle layer of heart
Cardiac muscle for contraction
Endocardium
Internal layer of heart
Endothelial cells
Lines lumen of four chambers
Lines cusps of valves
Diastole
Ventricles relax
Atria contract
Systole
Ventricles contract atria relax
Persistent ductus arteriosus
Congenital heart defect when ligamentum anteriorum doesn’t close after birth
Left coronary arteries
Anterior interventricular (LAD)
Circumflex
Left (obtuse) marginal
Right coronary arteries
Right marginal artery
Usually posterior interventricular (PDA) but not always
Posterior interventricular coronary artery (PDA)
usually comes off of right coronary but can come off of left circumflex branch of left carotid artery
Determines dominant side of heart
Supplies adjacent areas of both ventricles and sends perforating intrerventricular septal branches into IV septum
Suclus (plural is sulci)
Depression in the heart where coronary veins run
What is in the coronary sulcus
Right cornary artery
Left coronary artery
Circumflex artery
Coronary sinus
What is in the interventricular sulcus
Anterior interventricular artery (LAD)
Posterior interventricular artery (PDA)
Middle cardiac vein
Where does right coronary artery originate
Right aortic sinus
Where does left coronary artery originate
Left aortic sinus
Branches of right coronary artery
SA (sinoatrial) nodal branch
Acute marginal (right marginal) branch
AV (atrioventricular) nodal branch
Posterior interventricular branch in 70-80%
Marginal artery (acute marginal or right marginal branch)
Supplies right border of heart
Branches. at RCA and approaches inferior heart and goes towards apex
AV nodal artery
From right coronary artery
Supplies small branch of AV node
Left anterior descending (LAD) artery
Branch of left coronary artery
Supplies both ventricles and anterior 2/3 of interventricular septum.
Collateral circulation
Alternate circulation around blocked artery or vein.
Happens in LAD occlusions caused by atherosclerotic disease
Circumflex branch artery
Branch of left coronary artery
Travels to left coronary sulcus and base/diaphragmatic surface of heart
Left (obtuse) marginal artery
Branc of circumflex artery
Supplies left ventricle
What does the right coronary artery supply
Right atrium
Most of right ventricle
Diaphragmatic surface of left ventricle
Posterior third of IV septum
SA node
AV node
What does the left coronary artery supply
Left atrium
Most of left ventricle
Part of right ventricle
Anterior 2/3 of IV septum
Bundle of His
Where does coronary sinus empty
Right atrium
Great cardiac vein
Runs with anterior interventricular artery
Dilates into coronary sinus
Small cardiac vein
Runs with Right marginal artery
Middle cardiac vein
Runs with. posterior interventricular artery
Cardiac veins
Coronary sinus
Great cardiac vein
Small cardiac vein
Middle cardiac vein
Drain deoxygenated blood from myocardium and other heart tisues
What three veins drain directly into right atrium
SVC
IVC
Coronary sinus
Right atrial appendage (auricle)
Muscular pouch on right atrium.
Increases capacity of atrium as it overlaps ascending aorta.
“add-on room)
Pectinate muscles
Rough myocardium on internal surface of auricle
Found in right and left atrium (mostly right)
Sinus venarum
Smooth thin walls of right atrium.
SVC and IVC empty here
Crista terminalis
Extends from SVC to IVC
Separates rough and smooth portions of right atrium.
SA node located here
Fossa ovalis
Interatrial septum.
Internal vertical ridge
Open in fetus so lungs are bipased.
First breath changes pressure and causes flap to close
Tricuspid valve
Valve between right atrium an right ventricle
Three leaflets
Open during diastole
Closed during systole preventing backflow into RA
Triangle of Koch
In the right atrium.
Important for atrioventricular catheter ablation
Defined by borders: septal leaflet of tricuspid, tendon of todaro, ostium of coronary sinus
Chordae Tendinae
Fibrous cords
Connect cusps of AV valves to papillary muscles
Papillary muscles
Specialized trabeculae carneae
Elevations of ventricular myocardium
Attach to AV valve leaflets via chordae tendinae
Keep AV valves from prolapsing backwards into atria when closing during systolic contraction of ventricles
Trabeculae carnae
Projeciting ridges of myocardium
Moderator band
Single specialized trabecula
Carries part of cardiac conductoin ysstem to anterior wall of right ventricle
What does the pulmonary trunk give rise to
Pulmonary arteries
Stenosis
Heart valve narrowed
Leaflets or cusps of valve may thicken, stiffen, or fuse together
Can occur with aging or calcification on annulus keeping valve from opening
Increases pressure across valve
Two parts of interventricular septum
Muscular
Membranous
Membranous part of interventricular septum
Thin
Continuous with fibrous skeleton of heart
Muscular part of interventricular septum
Thick
Bulges into cavity of right ventricle because of higher blood pressure in left ventricle
Tetralogy of fallot
Caused by combination of four heart defects present at birth.
1.Narrowing of pulmonic valve
2.Ventricular septal defect (hole between ventricles)
3.Shifting of aorta
4.Right ventricular hypertrophy
Where does deoxygenated blood go
Right atrium
Where does oxygenated blood from pulmonary veins go
Left atrium
Cardiac conduction system
SA node
AV node
Bundle of His
Bundle branches
Purkinje fibers
SA node fire rate
60-100 bpm
AV node fire rate
40-60 bpm
Purkinje fibers fire rates
20-40 bpm
What artery supplies SA node
Right coronary artery in 60% of people
Left coronary artery in 40% of people
Why is AV firing rate slower than SA
Buffer to ensure all of the blood is in the ventricles before contraction
Bundle of His
Bridge between atrial adn ventricular myocardium
Devides into righ alndleft bundle branches that then become into purkinje fibers at apex and up the lateral walls
