ANAT Finals 2 - Heart Anatomy PDF

PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 OUTLINE Ø OBLIQUE SINUS...

PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 OUTLINE Ø OBLIQUE SINUS- an inverted U-shaped cul-de-sac reflection; less commonly accessed in surgery I. Pericardium........................................................................... 1 Ø TRANSVERSE SINUS- the relatively short horizontal space II. Heart Overview.................................................................. 2 between the reflection of the serous pericardium around the aorta and pulmonary trunk and the reflection around III. Heart Structure.................................................................... 7 the large veins; key for clamping the aorta in surgery IV. Conduction System of the Heart...................................... 9 V. Reading assignment (Triangle of Koch)........................... 9 D. PERICARDIAL NERVE SUPPLY VI. Checkpoint........................................................................ 10 Ø PHRENIC NERVE- supplies the parietal layer of the serous VII. References......................................................................... 10 pericardium and the fibrous pericardium. Ø VAGUS NERVE – Supplies the visceral layer of the serous PERICARDIUM pericardium: Parasympathetic CLINICAL CORRELATION Figure 1: Pericardium and its layers Ø A fibrous sac that encloses the heart and the roots of the great vessels. Figure 2: Pericardial clinical correlation Ø Function: restrict excessive movement of the heart as a whole and to serve as a lubricated container in which the A. CARDIAC TAMPONADE heart can contract freely. Ø Condition where there is accumulation of excess fluid Ø Lies within the middle mediastinum (e.g., blood or pericardial fluid) in the pericardial cavity. Ø Posterior to the body of the sternum and the 2nd to 6th This fluid accumulation puts pressure on the heart, limiting costal cartilages and anterior to the T5 to T8. its ability to expand and fill with blood, which can severely affect heart function A. FIBROUS PERICARDIUM Ø Can occur secondary to stab or gunshot wounds when Ø Strong, fibrous, outer layer sac chambers of the heart have been penetrated. Blood Ø Fuses with the outer coats of the great blood vessels escapes into the pericardial cavity and can restrict the passing through it (the aorta, pulmonary trunk, superior filling of the heart. and inferior venae cave, pulmonary veins) Ø Manifested by 3 Clinical Signs: Ø Attaches firmly below to the central tendon of the BECK’s Triad: diaphragm o Muffled Heart Sound Ø Attaches in front of the sternum via sternopericardial o Jugular Vein Distention ligament o Hypotension B. SEROUS PERICARDIUM B. PERICARDIAL EFFUSION Ø Lines the fibrous pericardium and coats the heart Ø Accumulation of excess fluid in the pericardial cavity. Ø 2 layers: parietal and visceral layers PARIETAL LAYER NOTE: cardiac tamponade is a complication of pericardial effusion o Lines inner surface of the fibrous pericardium where the fluid buildup becomes severe enough to impair heart o Reflects around the roots of the great vessels to function significantly become continuous with the visceral layer of the serous pericardium that closely covers the heart C. PERICARDITIS VISCERAL LAYER Ø Inflammation of the pericardium o Closely applied to the superficial surface of the Ø PERICARDIAL FRICTION RUB- produces by roughening of heart the visceral and parietal layers of serous pericardium by o Often called the epicardium inflammatory exudate in acute pericarditis o Pericardial cavity- slit like space between Ø CONSTRICTIVE PERICARDITIS- occurs when the fibrous parietal and visceral layers. Normally contains 50 pericardium becomes too rigid because of mL of pericardial fluid that acts as lubricant to inflammation. This results in heightened resistance to facilitate movement. movement of heart and blood flow C. PERICARDIAL SINUSES D. PARACENTESIS Ø Spaces posterior to the heart formed by the reflections of the serous pericardium. DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 1 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 Ø Process of aspirating pericardial fluid from pericardial cavity due to excessive amounts accumulated in Ø DIAPHRAGMATIC (INFERIOR) pericarditis. Formed by right and left ventricles (separated by the Ø Needle is introduced to the left of the xiphoid process in an upward and backward direction at an angle of 45 NOTE: right ventricle and left ventricle are separated by the anterior interventricular groove degrees to the skin. Ø Lungs and pleura are not damaged due to the presence posterior interventricular groove) of cardiac notch. Inferior surface of the right atrium, also forms part of this surface HEART Ø BASE (POSTERIOR) Formed by the left atrium Lies opposite the apex BORDERS Figure 3: The anterior surface of the heart; the fibrous pericardium and the parietal serous pericardium have been removed. Note the presence of fat Figure 4: Blue line:Superior border; Yellow line: Left border; Green line: beneath the visceral serous pericardium in the atrioventricular and Inferior border; Red line: Right border interventricular grooves. The coronary arteries are embedded in this fat. Ø SUPERIOR BORDER (highlighted in blue) Ø The heart is an enlarged, internally subdivided blood Root of great vessels (two atria) and extends from a vessel specialized for pumping. point on the 2nd left costal cartilage to a point on Ø It’s myocardial layer is composed largely of cardiac the 3rd right costal cartilage at the edge of the muscle sternum (∼1.3 cm) Ø Pyramid shaped Ø Contains four chambers- two atria and two ventricle Ø RIGHT BORDER (highlighted in red) Ø Atrioventricular valves- connects atrium and ventricle Right Atrium and extends from a point on the 3rd right Ø Atria pump blood to immediate adjacent ventricles costal cartilage (∼0.5in) and downward to a point on therefore are low-pressure chambers the 6th right costal cartilage (1.3 cm) from the edge Ø Ventricles pump arterial blood out of the heart, must of the sternum. impart pulmonary and systemic pulses of blood, therefore are comparatively high-pressure chambers. Ø LEFT BORDER (highlighted in yellow) Left Auricle and Left Ventricle (majority) and extends Ø Weight: 250-300 grams (fist size) from a point on the 2nd left costal cartilage (1.3 cm) Ø Vertebral levels: T5-T8 or T6-T9 from the edge of the sternum to the apex beat of the Ø Main blood supply: Coronary arteries heart ORIENTATION Ø INFERIOR BORDER, RIGHT MARGIN (highlighted in green) Ø Aligned obliquely within the thorax Right Ventricle and extends from the 6th right costal Ø Base lies opposite the apex cartilage (1.3 cm) from the sternum to the apex beat Ø Apex of the heart. Right atrium contributes a small portion. Formed by the left ventricle Directed downward, forward, and to the left Lies at the level of the 5th left ICS midclavicular line, 3.5 in. (9 cm) from the midline (aka the Point of Maximal Impulse PMI) Can usually be seen and palpated NOTE: Point of Maximal Impulse/ PMI: 5th Left ICS Midclavicular SURFACES Ø STERNOCOSTAL (ANTERIOR) Formed by the right atrium and the right ventricle which are separated from each other by the vertical atrioventricular groove (coronary sulcus) DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 2 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 AUSCULTATORY VALVES Mainly connective tissue and functions for protection. NOTE: Surrounds the heart and root of the great blood S1: Sound produced when mitral and tricuspid valve close which vessels. occurs almost simultaneously. Clinically, this corresponds to the pulse. Note: S2: Sound produced by the closure of both the aortic and pulmonary o Normal Heart Rate: 60 to 100 bpm valves o Tachycardia: a heart rate higher than normal. o Bradycardia: a heart rate lower than normal. § Hence, 100 is AREA LOCATION OF TIMING OF SOUND tachycardia. SOUND AORTIC 2nd ICS, RPSL Heard during CHAMBERS S2 PULMONARY 2nd ICS, LPSL Heard during S2 ERB’S POINT 3rd ICS, LPSL Heard during S2 TRICUSPID 5TH ICS, LPSL Heard during S1 MITRAL 5TH ICS, MCL Heard during S1 Figure 5: Auscultatory points mnemonic: APE To Man (A: aortic; P: pulmonic; E: erb’s; To: tricuspid; Man: Mitral) LAYERS OF THE HEART Figure 7: Review of blood flow: Superior Vena Cava / Inferior Vena Cava » Right Atrium » Tricuspid Valve » Right Ventricle » Pulmonic Valve » Pulmonary Artery » Lungs (oxygenation). Blood returns to heart via Pulmonary Veins » Left Atrium » Mitral Valve (Bicuspid Valve) » Left Ventricle » Aortic valve » Aorta » Systemic Circulation A. RIGHT ATRIUM Ø Consists of: Atrium proper (main cavity) Auricle: small earlike out pouching Ø SULCUS TERMINALIS: Vertical groove on the outside of the heart, at the junction between the right atrium and the right Figure 6: Layers of the heart auricle. Ø CRISTA TERMINALIS: A ridge formed by the sulcus groove; Ø ENDOCARDIUM marks the boundary between the atrium proper and the Inner lining of heart chambers; smooths blood flow. auricle. Ø MYOCARDIUM Ø INFERIOR SURFACE: Divided into two parts, each with a distinct Middle muscular layer; pumps blood. embryological origin and are separated by crista terminalis. Functionally the main constituent of the heart. Part of atrium posterior to the ridge: smooth – walled and Thickest layer of all three heart layers. derived embryologically from the sinus venosus. Histologically, it is comprised of cardiomyocytes. Part of the atrium anterior to the ridge: roughened or o Cardiomyocytes communicate through trabeculated by bundles of muscle fibers (pectinate special intercellular bridges called intercalated muscles), which run from the crista terminalis to the discs. auricle; derived embryologically from the primitive atrium. Ø EPICARDIUM External layer; protects heart and reduces friction. Also known as visceral layer of serous pericardium. DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 3 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 B. AURICLES primum of the Ø Small earlike outpouching extension of the atrium embryonic Ø Accommodate extra volume of blood then pumped back heart to the ventricle forms from the Ø RIGHT AURICLE lower edge of Rough, muscular, and irregular in shape. the septum Extends from the right atrium. secundum Increases the volume of the right atrium The fossa ovalis and annulus ovalis lie on the atrial septum, which separates Ø LEFT AURICLE the right atrium from the left atrium Smaller, smoother, and more conical. Ductus arteriosus: conducts blood Extends from the left atrium. from the pulmonary trunk to the Increases the volume of the left atrium aorta, bypassing the lungs o Remnant: ligamentum C. OPENINGS INTO THE RIGHT ATRIUM arteriosum Ø SUPERIOR VENA CAVA o This ligament connects the Opens into the upper part of the right atrium bifurcation of the pulmonary No valve trunk to the lower concave Returns the blood to the heart surface of the aortic arch From the upper half of the body Ø INFERIOR VENA CAVA Larger than the superior vena cava Opens into the lower part of the right atrium FETAL CIRCULATION Guarded by a rudimentary, non – functioning valve Returns the blood to the heart from the lower half of the body Ø CORONARY SINUS 2 : where Great Cardian veir Drains Drains most of the blood from the heart wall Opens into the right atrium between the inferior vena cava and the atrioventricular orifice Guarded by a rudimentary, non – functioning valve Ø RIGHT ATRIOVENTRICULAR ORIFICE Lies anterior to the inferior vena caval opening Guarded by the tricuspid valve NOTE: Many small orifices of small veins also drain the wall of the heart and open directly into the right atrium. Figure 8: Fetal circulation FETAL REMNANTS Ø Oxygenated blood from placenta enters the fetus FEATURE FOSSA OVALIS ANNULUS OVALIS through the umbilical vein Ø Blood flows from the umbilical vein to the ductus venosus, DEFINITION Oval-shaped Fibrous ring or an accessory vessel that directs oxygenated blood depression in the border surrounding directly to the fetal liver interatrial septum the fossa ovalis Ø Blood then empties into the fetal inferior vena cava so LOCATION Right atrium of the Around the fossa oxygenated blood is directed to the right side of the heart heart ovalis in the Ø Because there is no need for the bulk of blood to pass interatrial septum through the lungs, it is shunted through the ductus COMPOSITION Thin, smooth tissue Fibrous tissue arteriosus as it enters the right atrium then the left atrium through an opening in the atrial septum, called the foramen ovale DEVELOPMENTAL Remnant of the Marks the boundary Ø From the left atrium, it follows the course of adult ROLE fetal foramen of the fetal foramen circulation into the left ventricle and into the aorta. ovale ovale Ø Most of the blood flow from the descending aorta is FUNCTION Marks the closure Provides structural- transported by the umbilical arteries back through the site of the foramen reinforcement umbilical cord to the placental villi, where new oxygen ovale around the fossa exchange takes place ovalis PRESENCE AFTER Present as a Present as a fibrous CLINICAL CORRELATION BIRTH depression after ring around the the foramen ovale foramen ovalis A. PATENT DUCTUS ARTERIOSUS NOTES: a shallow forms the Ø After birth, the ductus arteriosus normally constricts, later depression that upper margin closes, and becomes the ligamentum arteriosum marks the site of of the fossa Ø Failure to close may occur as an isolated congenital the fetal foramen Its floor abnormality or may be associated with congenital heart ovale represents the disease. persistent Ø A persistent patent ductus arteriosus results in high- septum pressure aortic blood passing into the pulmonary artery, DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 4 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 producing pulmonary hypertension and hypertrophy of BRANCHES: the right ventricle 1. RIGHT CONUS ARTERY/ CONUS ARTERIOSUS Ø TREATMENT: ligated and divided surgically supplies the anterior surface of the pulmonary conus and the upper part of the anterior wall of NERVE SUPPLY OF THE HEART the right ventricle Ø EXTRINSIC NETWORK: Formed by sympathetic and proximal segment of the right coronary artery parasympathetic fibers of the autonomic nervous system extends to the right coronary ostia and ends at SYMPATHETIC SUPPLY right cardiac margin o Originates in upper thoracic spinal cord segments 2. RIGHT MARGINAL ARTERY o Activation of results in cardiac largest and runs along the right margin of acceleration, increased force of anterior surface towards the apex contraction of the cardiac muscle, and dilatation of the coronary arteries. 3. ANTERIOR VENTRICULAR BRANCH PARASYMPATHETIC SUPPLY Two to three anterior ventricular branches o Comes from the vagus nerves supply the anterior surface of the right ventricle o Activation results in a reduction in the rate 4. POSTERIOR INTERVENTRICULAR BRANCH (POSTERIOR and force of contraction of the heart and DESCENDING ARTERY) core constriction of the nary arteries. Usually, a branch of right coronary artery but M may originate from circumflex branch of the Ø INTRINSIC NETWORK: Formed by conducting system of the left coronary artery. heart Runs toward apex in the posterior Specialized cardiac muscle cells designed to interventricular groove. generate rhythmic cardiac impulses Gives off branches to right and left ventricles Conduct and coordinate the intrinsic contractions of including inferior wall. the myocardium Supplies branches to posterior part of Independent of the extrinsic nervous system ventricular septum Normal heart rate: 70 to 90 beats per minute in the resting adult 5. POSTERIOR VENTRICULAR BRANCH Supply diaphragmatic surface of the right ARTERIAL BLOOD SUPPLY ventricle. Ø The right and left coronary arteries provide arterial supply Atrioventricular nodal branch – supplies AV to the heart. node. Ø First branches of the aorta, arising from the ascending aorta immediately above the aortic valve 6. RIGHT POSTERIOR ATRIAL BRANCH Ø Initially pass around the opposite sides of the pulmonary Exists as a solitary branch that supplies both trunk right and left atria. 7. SINUATRIAL NODAL ARTERY Supplies SA node and the right and left atria. 35% of individuals, it arises from left coronary artery. B. LEFT CORONARY ARTERY Ø Larger than the right coronary artery Ø Arise from the left aortic sinus of the ascending aorta, passes forward between the left atrial or auricular appendage and the left side of pulmonary trunk and runs in coronary sulcus. Ø Responsible for supplying a larger territory (left atrium, majority of the left ventricle, and most of the IVS and left circumflex artery). Figure 9: Arterial blood supply in anterior view BRANCHES: 1. ANTERIOR INTERVENTRICULAR ARTERY (LEFT A. RIGHT CORONARY ARTERY ANTERIOR DESCENDING ARTERY/ LAD) Ø Arises from the right aortic sinus of the ascending aorta Runs downward along the ventricular septum Ø Runs forward between the right side of the pulmonary in the anterior interventricular groove to the trunk and the right auricle, descends almost vertically in apex of the heart the right atrioventricular groove (coronary sulcus) LEFT ANTERIOR Passes around the apex of the heart to enter Ø At the inferior border of the heart, it continues posteriorly DESCENDING the posterior interventricular groove and along the AV groove to anastomose with the left ARTERY anastomose with the terminal branches of the = WIDOW-MAKER coronary artery in the posterior interventricular groove. posterior interventricular branch of the right ARTERY coronary artery *due to its deadly Ends at the apex of the heart in about 1/3 of manifestation during individuals. blockage The lateral or diagonal artery may arise directly from the trunk of the left coronary artery DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 5 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 Supplies a large portion of the heart, particularly the anterior wall of the left ventricle, the anterior 2/3 of the interventricular septum, and the apex of the heart. LAD artery supplies a significant portion of the left ventricle, which is responsible for pumping oxygenated blood to the rest of the body Left conus artery supplies the pulmonary conus Once blocked, it can lead to MYOCARDIAL INFARCTION / HEART ATTACK LAD supplies the most important area of the heart. 2. CIRCUMFLEX BRANCH Follows the coronary sulcus around left border to the posterior surface of the heart. Terminates in the coronary sulcus on the posterior aspect before reaching the crux of the heart. Overlapped by the left atrial proximally appendage. 3. LEFT MARGINAL BRANCH Follows left margin of the heart. Supplies the left ventricle RIGHT CORONARY ARTERY DIVISION AREAS BEING SUPPLIED Sinoatrial nodal branch Sinoatrial (SA) node (heart's natural pacemaker) Right atrial branch Right atrium Right Marginal Branch Right ventricle (lower part) Posterior interventricular Posterior part of the branch (PIV) interventricular septum, posterior walls of both ventricles Atrioventricular (AV) Atrioventricular (AV) nodal branch node LEFT CORONARY ARTERY DIVISION AREAS BEING SUPPLIED Left Anterior Descending Anterior wall of left (LAD) artery ventricle, anterior 2/3 of interventricular septum, apex of the heart Diagonal Branches Anterior wall of left ventricle Left circumflex artery Left atrium, lateral and posterior walls of left ventricle Obtuse marginal Lateral wall of left branches ventricle DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 6 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 I. HEART STRUCTURE Ø Openings into the right atrium: OVERVIEW a) Superior Vena Cava (SVC) Ø The heart wall has three layers: Blood returns to the heart from the upper half of 1. Visceral layer of serous pericardium (epicardium) the body via SVC o External layer Opens into the upper part of the right atrium 2. Cardiac muscle (myocardium) No valve o Middle layer b) Inferior Vena Cava (IVC) 3. Endothelium (endocardium) Blood returns to the heart from the lower half of o Internal layer the body through the IVC Ø Two internal septa divide the heart into four chambers: Larger than SVC 1. Atrial (interatrial) septum Opens into the lower part of the right atrium o Separates the right and left atria Valve of IVC: rudimentary, nonfunctioning (in o Runs from anterior wall of the heart backward and the adult) valve, guards the opening of the IVC. to the right This prevents back flow of blood 2. Ventricular (interventricular) septum c) Coronary Sinus o Separates the right and left ventricles Drains most of the blood from the heart wall o Lies obliquely Opens into the right atrium between the inferior Right surface facing downward vena cava and the atrioventricular orifice Right and left surface facing backward Guarded by a rudimentary, non – functioning and to the left valve o Has lower, thicker muscular part and a small upper, d) Right atrioventricular orifice thinner membranous part Regulates by right atrioventricular valve o The anterior and posterior interventricular grooves (tricuspid valve) on the surface of the heart mark the position of the Lies anterior to the IVC opening ventricular septum Ø Fetal remnants associated (at the atrial septum): o Fossa ovalis Shallow depression that marks the site of the II. CHAMBERS OF THE HEART foramen ovale in the fetus Remnant of foramen ovale in the fetal heart which allows right to left shunting of blood to bypass the lungs. Closes once the newborn takes its first breath. o Annulus ovalis Forms the upper margin of the fossa Lies on the atrial septum Ø NOTE: o The floor of the fossa represents the persistent septum primum of the heart of the embryo and the annulus is formed from the lower edge of the septum secundum. B. RIGHT VENTRICLES Ø Receives oxygenated blood from the right atrium and pumps it through the pulmonary orifice which is guarded by the Figure 2. Left atrium and Left Ventricle of the Heart pulmonary valve into the pulmonary artery. Ø Triangular in shape. Ø Forms the majority of the anterior border of the heart. A. RIGHT ATRIUM Ø Blood flows through the right atrioventricular orifice passing Ø Consists of two parts: from the right atrium to the right ventricle. a) Main cavity (atrium proper) Ø Infundibulum (Conus arteriosus) b) Auricle o Funnel-shaped narrowing of the the ventricular cavity § Small earlike outpouching where the cavity approaches the pulmonary orifice then Ø Sulcus terminalis: vertical groove, runs on the outside of the to the pulmonary trunk heart at the junction between the right atrium and the right Ø Trabeculae carneae auricle forms a matching ridge, the crista terminalis on the o Ridges formed of muscle nundles. inside. o Give the walls a spongelike appearance o The crista marks the boundary between the atrium proper and the auricle Ø The atrium proper is smooth walled and forms from the embryonic sinus venosus Ø The auricle is roughened or trabeculated by bundles of muscle fibers, the musculi pectinati (pectinate muscles). This area develops from the embryonic primitive atrium DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 7 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 o Three forms: Pillars or Papillary Project inward and are DIFFERENCE BETWEEN RIGHT AND LEFT ATRIUM Muscle anchored by their base to the RIGHT ATRIUM LEFT ATRIUM ventricles their apices are I Receives deosygenated blood Receives oxygenated blood attached to fibrous cords of from SVC, IVC and coronary from four pulmonary veins chordae tendineae which are sinus in turn attached to the 3 Right AV orifice guarded by Left AV orifice guarded by tricuspid valves cusps. tricuspid valve mitral (bicuspid) valve By contracting, the papillary Present crista terminalis ~ Absent crista terminalis ↓ muscles pull on the chordae tendineae to prevent prolapse of the valve leaflets during DIFFERENCE BETWEEN RIGHT AND LEFT VENTRICLES ventricular systole. RIGHT VENTRICLES LEFT VENTRICLES Chorda Tendenae aka Receives deoxygenated blood Receives oxygenated blood Heartstrings from the right atrium from the left atrium Moderator band “Supramarginal band” Pums blood to the lungs tjrough Pumps blood to the systemic attached to the end of the oulmonary orifice into the circulation through the aortic ventricular wall, being free in pulmonary artery orifice the middle. Thin walls Thick walls Crosses the ventricular cavity Lower intraventricular pressure Higher intraventricular pressure from the septal to the anterior Present moderator band ↑ Absent moderator band wall. ↑ Conveys the right branch of the atrioventricular bundle which is part of the conducting system III. VALVES OF THE HEART of the heart. Resists overdistension of the anterior ventricular wall. Prominent ridge Attached along the entire length on one side to form the ridges along the interior surface of the ventricle. Ø Outflow Portion o “Conus arteriosus” o Leads to pulmonary artery o Located in the superior aspect of the ventricle o Derived from the embryonic bulbos chordis o Visibly different from the rest of right ventricle with smooth walls and no trabeculae carneae Ø Inflow Portion Figure 3. Valves of the Heart o Covered by trabeculae carneae C. LEFT ATRIUM PULMONIC VALVE Ø Also contains main cavity and an auricle Ø The interior of the left atrium proper is smooth, but the left Ø Guards the pulmonary orifice auricle possesses pectinate muscle ridges as in the right auricle Ø Consists of three semilunar cusps, right and left Ø No crista terminalis AORTIC VALVE Ø Fossa ovalis is not distinctive Ø Guards the aortic orifice Ø Forms the greater part of the base (posterior surface of the Ø Has three cusps ( right coronary, left coronary, posterior) - heart) RIGHT ATRIOVENTRICULAR VALVE (TRICUSPID VALVE) - Ø Openings are the four pulmonary veins, two from each lung, Ø Regulates the right atrioventricular orifice open through the posterior wall and have no valves Ø Lies anterior to the inferior vena cava opening Ø Receives oxygenated blood from the 4 pulmonary veins and Ø Consists of three cusps (anterior, posterior, septal) pumps it to the left AV orifice which is guarded by the mitral LEFT ATRIOVENTRICULAR VALVE (MITRAL VALVE) valve into the left ventricle. Ø Guards the atrioventricular orifice Ø The left atrioventricular orifice is guarded by the mitral valve Ø Consists of two cusps (one anterior and one posterior) D. LEFT VENTRICLES Ø Blood enters the left ventricle from the left atrium through the left atrioventricular orifice and then leaves the ventricle through the aortic orifice Ø Walls are three times thicker than those of the right ventricle Ø Left intraventricular blood pressure is six times higher than right ventricle. Ø Trabeculae carnae and two large papillary muscles are present Ø Absent of Moderator band DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 8 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 IV. CONDUCTING SYSTEM OF THE HEART D. RIGHT AND LEFT BUNDLE BRANCHES OVERVIEW Ø Divides into right and left bundle o Right bundle branch Ø The conducting system of the heart is a network of specialized Passes down on the right side of the ventricular cardiac muscle cells designed to generate rhythmic cardiac septum to reach the moderator band, where it impulses and to conduct and coordinate the intrinsic crosses to the anterior wall of the right ventricle. contractions of the myocardium. It becomes continuous with the fibers of the Ø The components of the conducting system are: Purkinje plexus on the right side of the & Sinoatrial (SA) node Atrioventricular (AV) node o Left bundle branch Atrioventricular bundle (bundle of His) Pierces the ventricular septum Right and left bundle branches Usually divides into two branches anterior and Subendocardial branches (terminal conducting posterior fibers, Purkinje fibers) Continuous with the fibers of Purkinje plexus on SINOATRIAL the left side A. SINUATRIAL num (SA) NODE E. SUBENDOCARDIAL BRANCHES (TERMINAL CONDUCTING FIBERS, PURKINJE FIBERS) Ø Highest conduction velocity V. READING ASSIGNMENT A. WHAT IS TRIANGLE OF KOCH? Figure 1. Heart Conduction System Ø AKA Pacemaker of the heart Ø Derived from sinus venosus Ø Primary impulse initiator and regulator of the heart Ø Also known as the triangle of atrioventricular triangle Ø Locates at the superior posterolateral wall of the right atrium Ø Triangle landmark for locaring Atrioventricular (AV) Node near the opening of superior vena cava Ø Located at the base of thr right atrium Ø Landmark for the Superior Vena Cava: Sulcus Terminalis Ø Bordered by; Sulcus Terminalis- junction between the right atrium and o Anterior: Right atrioventricular valve venus sinus o Base: Opening of Coronary Sinus Ø Specific Layer of the SA node is located in the Subepicardial o Posterior: Tendon of Todaro (inferior pyramidal layer of the heart space) St Ø Blood supply: Majority comes from the right coronary artery 60 % -RCA. B. WHICH HAS THICKER WALLS PULMONARY ARTERY VS 40% comes from the left coronary artery PULMONARY VEIN 40 % LCA - B. ATRIOVENTRICULAR (AV) NODE Ø Located on the right, lower side of the strial septum Ø Atrial excitation wave stimulates the AV node as the wave passes through the atrial myocardium C. ATRIOVENTRICULAR BUNDLE (BUNDLE OF HIS) Ø Originates from the AV node Ø Pierces the fibrous skeleton of the heart Ø Sole myocardial connection between atria and ventricles Ø Only route along which the cardiac impulse can travel from the atria to the ventricles DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 9 of 10  PINES CITY COLLEGES 0P.01 F.06 Trans TitleGREAT VESSELS HEART AND DR. ABRAHAM CINIO | NOVEMBER 26, 2024 VI. CHECKPOINT 1. Aka WIDOW-MAKER artery: a. Left ascending b. Left anterior descending 2. Point of maximal impulse is located at: a. Left 5th ICS midclavicular line b. Left 5th ICS parasternal line 3. Gives spongy-like appearance of heart a. Trabeculae carneae b. Conus arteriosus 4. Fetal remnants: a. Fossa ovalis b. Annulus ovalis c. Both 5. Patent ductus arteriosus is normal in adults a. True b. False b. False 5. c. Both 4. a. Trabeculae carneae 3. a. Left 5th ICS midclavicular line 2. b. Left anterior descending 1. VII. REFERENCES Netter, F. H. (2014). Atlas of Human Anatomy (6th ed.). Saunders Elsevier Moore, K., Dalley, A. & Agur, A. (2018). Clinically Oriented Anatomy 8th Edition. Wolters Kluwer A. G. Cinio (personal communication, November 26, 2024) Wineski, L. E. (2019). Clinical Anatomy by Regions (10th ed.). Wolters Kluwer Vascovic, J. (2023) Heart. Kenhub. https://www.kenhub.com/en/library/anatomy/heart DITAN, KINDAO, VICENTE, IBAT, CARAJAY, FERNANDEZ Page 10 of 10  PINES CITY COLLEGES 0P.01 F.08 Trans Title SYSTEM AND THE THORACIC DUCT THE AZYGOS Lecturer | Date OUTLINE I. The Azygos System.............................................................. 1 II. Azygos Vein....................................................................... 2 III. Hemiazygos Vein............................................................... 3 IV. Accessory Hemiazygos Vein............................................. 4 V. The Sympathetic Trunk...................................................... 4 VI. Thoracic Lymphatics......................................................... 4 VII. Clinical Correlation............................................................ 7 VIII. Checkpoint........................................................................10 IX. References........................................................................10 I. THE AZYGOS VENOUS SYSTEM A. OVERVIEW Creates an important connection between the Superior Vena Cava (SVC) and Inferior Vena Cava (IVC) Azygos and Hemiazygos systems create vital collateral pathways Becomes a vital shunt in cases of obstruction of major pathways Figure 2. Azygous Venous System B. VEINS Consists of THREE VEINS which form longitudinal collecting trunks into which the intercostal veins drain: VEINS AZYGOS (RIGHT) Main Azygous vein Unpaired HEMIAZYGOS Inferior Hemiazygous vein / (LEFT) Hemiazygous The azygos vein and its main tributary, the hemi-azygos vein, usually arise from “roots” arising from the posterior aspect of the IVC and/or renal vein, respectively, which merge with the ascending lumbar veins. ACCESSORY Figure 1. Diagrammatic illustration showing the relation of HEMIAZYGOS Superior Hemiazygos Vein Azygos vein to SVC and IVC Consists of several longitudinal vessels on both sides of the vertebral column that collects venous blood from: o Viscera of Mediastinum o Back, Thoracic and Abdominal walls ○ Blood will drain into this system from the lower extremities and the abdominal region back to the heart if there is a blockage in the inferior vena cava These veins ascend and empty into the SVC o Some veins from thoracic viscera may also drain into this system and their anastomosis with abdominal veins Figure 3. Three veins PILOY, ANG, CALIAG Page 1 of 10  PINES CITY COLLEGES 0P.01 F.08 Trans Title SYSTEM AND THE THORACIC DUCT THE AZYGOS Lecturer | Date The three vein drains blood from the posterior parts of the: Also known as the Vena Azygos Major / Major Azygos Vein (M: Posterior BED PAIn) Drains the intercostal veins and has an arch similar to the o Intercostal Spaces Aorta. o Abdominal wall Arch of the Azygous Vein o Pericardium o This arch will actually curve on the superior o Diaphragm portion of the hilum of the right lung and courses o Bronchi to the eparterial bronchus, and enters into the o Esophagus superior vena cava. Relationship with the Diaphragm: A. ANATOMICAL VARIATIONS o Other tributaries specifically the lower portion Origin and anatomical course of the azygous vein are enters the diaphragm via the aortic opening quite VARIABLE (aortic hiatus). Usually, there is a singular azygos vein on the right side of o The aortic opening will transmit the aorta, the body azygous vein, and the thoracic duct o However, the azygos vein can be occasionally The union of the right ascending lumbar vein and the right located in the midline or as 2 independent veins subcostal vein in the abdomen. Usually, the azygos vein originates at the level of lumbar Enters the chest through the: AORTIC HIATUS (In the vertebra, BUT may originate may be further up diaphragm A12) Lumbar aspect of azygos vein: Ascends along the: Antero-lateral surface of the thoracic o Can ascend anterior to the lumbar vertebra and vertebrae pass behind R. crus or cross aortic hiatus (where It ascends through the aortic opening in the diaphragm on the Aorta Pierces the Diaphragm) to the R. of the right side of the aorta and up to the level of the 5th cisterna chyli (Dilated Lymph Sac) thoracic vertebra. Common trunk of R. ascending lumbar vein and R Arches ventrally to the: RIGHT MAIN BRONCHUS (At the level subcostal vein joins the azygos vein anterior to the body of the 5th-6th Thoracic vertebra) of T12 DRAINS (mainly) into the SVC o However, if lumbar segment is absent, this trunk o More Rarely (drains at the): may form the azygos vein. ▪ Right Brachiocephalic Vein ▪ Right Subclavian Vein ▪ Intrapericardial SVC ▪ Directly into the right atrium Other tributaries: o Eight Lower Right Intercostal Veins o Right Superior Intercostal Vein o Superior and Inferior Hemiazygos Vein o Various Mediastinal Veins o Esophageal Veins o Pericardial Veins o Bronchial Veins Figure 4: Tributaries Figure 5: Anatomic relations Figure 6. Arching of the Azygous vein over the SUPERIOR RIGHT MAIN LOBAR BRONCHUS as it drains into the SVC B. ANATOMICAL RELATIONS II. AZYGOS VEIN PILOY, ANG, CALIAG Page 2 of 10  PINES CITY COLLEGES 0P.01 F.08 Trans Title SYSTEM AND THE THORACIC DUCT THE AZYGOS Lecturer | Date The following structures are located Posterior to the o · At the Level of 8th Thoracic Vertebrae Azygous Vein: Turns to the right to join and DRAIN into the Azygous Vein o Anterior Longitudinal Ligament Receives as tributaries to some: o Right posterior intercostal arteries o Lower Left Intercostal Veins o T4-T12 vertebral bodies o Mediastinal Veins In the posterior thorax, the azygos vein is located posterior Travels on the LEFT side of the Vertebral Column to the recess of the Right pleural sac and esophagus. o Intraabdominally enters the Thoracic region (up RELATION OF AZYGOUS VEIN WITH DRAINAGE OF to the 9th Thoracic Vertebrae) BRONCHI: o Then, crosses the midline at the level of the 8th o The Bronchi, Connective tissue of the lung, Thoracic Vertebrae (Behind the Aorta, Visceral Pleura receives blood supply from the Esophagus, Thoracic duct) Bronchial Arteries (branches of Descending. TRIBUTARIES to the HEMIAZYGOS come from: Aorta) o Lower 4 or 5 left intercostal veins o The Bronchial veins which communicate with o Lower end of the accessory hemiazygos the Pulmonary Vein drains in the Azygous and May drain directly to the inferior azygos before entering Hemiazygos Veins the azygos vein RELATION OF AZYGOUS VEIN WITH DRAINAGE OF o Mediastinal vein ESOPHAGUS o Lower left esophageal vein o The veins from the U/3 of the Esophagus drains Usually connected to the LEFT RENAL VEIN & formed by: into the Inferior Thyroid Veins o Esophageal and Mediastinal tributaries o Veins from the M/3 of the Esophagus drains into o Common trunk of left ascending lumbar vein the Azygous Veins o Left Subcostal veins o At the L/3 of the Esophagus is an important Portal o Lower 3 Posterior ICVs systemic venous anastomosis Ascends: o Area of anastomosis of: (2) o Anterior to the Vertebral Column before crossing ▪ Esophageal Tributaries of the Azygous the column posterior to the Aorta, Esophagus Vein and Thoracic duct at the level of T8 Vertebrae ▪ Esophageal Tributaries of the LGV (Left gastric V.) Note: (Accdg. to Dr. Cinio’s Lecture) Hence, LGV drains the Portal The hemiazygous and the accessory hemiazygous veins Vein will turn from the left and will drain directly to the azygous vein on the right side, crossing the midline at the level of the T9 vertebra passing along behind the Aorta, esophagus, and the thoracic duct. Figure 7. Tributaries of the Azygous vein AZYGOS ARCH- curves/arches just above the superior lobar bronchus to drain into the superior vena cava o Landmark: Hilum/cuff III. HEMIAZYGOS VEIN Figure 8. Tributaries of the Inferior Hemiazygos Vein Also known as the Vena Azygos Minor Inferior / Minor Inferior Azygos Vein / Inferior Hemiazygos Vein Located on the left Formed via the union of: IV. ACCESSORY HEMIAZYGOS VEIN o* Left Ascending lumbar Vein Also known as the Vena Azygos Minor Superior / Minor *o Left Subcostal Vein Superior Azygos Vein / Superior Hemiazygous Vein Ascends through the: Left side of vertebral column ·o Left Crux of the Diaphragm PILOY, ANG, CALIAG Page 3 of 10  PINES CITY COLLEGES 0P.01 F.08 Trans Title SYSTEM AND THE THORACIC DUCT THE AZYGOS Lecturer | Date Veins from 3rd or 4th OCS Continuous above with the thoracic and below with the Formed by UNION of 4th-8th ICVs pelvic parts. o Formed by the veins of 4-8th ICS The right sympathetic trunk lies behind the right border of o Sometimes by the Left Bronchial Veins the inferior vena cava; the left sympathetic trunk lies Descends to the Left of the vertebra to join the Azygous close to the left border of the aorta Vein at the level of 7th Thoracic Vertebra Crosses body of T8 Sometimes joins the Hemiazygos Veins and their common VI. THORACIC LYMPHATICS trunk drains in the azygos vein The lymphatic system drainage of the body Often continuous w/ or drained by the left superior ICV Clinical Importance: it will dictate spread of tumors Note: Collects lymph from virtually all parts of the body below Not all veins on the superior portion will drain into the the neck and upper limbs. accessory hemiazygous vein such as the 1st and 2nd Further, the upper ends of these vessels at the root of the intercostal vessels (this will drain to the azygous vein). neck, typically collect the drainage from the head, neck o Left Brachiocephalic Vein - one of the major and upper limbs. vessel present in the root of the neck ▪ Crosses the jugular notch and may bleed if exposed to surgical procedures ▪ This major vessel will drain to azygous vein Variation in some: the hemiazygous and the accessory hemiazygous veins will join as one trunk. Figure 10. Relationship of the Lymphatic Ducts and the Venous System Formed by 2 main trunks: A. Thoracic Duct B. Right Lymphatic Duct A. THORACIC DUCT Largest lymphatic vessel in the body and is located behind the subclavian artery Collects lymph from trunks including the lymphatic tissues that will drain the lower extremities (see Figure 7) More extensive because it drains the upper and lower portion of the body (right and left) Figure 9. The Azygos Venous System Around 75% of the lymph from the entire body passes through the thoracic duct, aside from the following: V. THE SYMPATHETIC TRUNK o Right upper limb o Right breast Visible and coursing along the paravertebral region o Right lung o Right side of the head and neck A. THORACIC SYMPATHETIC TRUNK More extensive because it drains the upper and lower Continuous above with the cervical and below with the portion of the body (right and left) lumbar parts of the sympathetic trunk Length: 18 inches / 38-45 cm (SNELL: 40 cm) It is most laterally placed structure in the mediastinum Diameter: 2 - 5 mm and runs downard on the heads of the ribs. Rate/Lymph flow in the thoracic duct: 60-190 ml/hr (L/day It leaves the thorax on the side of the body of the 12th = __________ ) thoracic vertebra by passing the medial aracuate ligament of the diaphragm. A.1 COURSE OF THE THORACIC DUCT Has 12 (often only 11) segmentally arranged ganglia, It runs from Superior aspect of the Cisterna chyli (a lymph each with a white and gray ramus communicans sac located at the L2 Vertebrae to the lower cervical passing to the corresponding spinal nerve. spine The first ganglion is often fused with the inferior cervical From the cisterna chyli: ganglion to form the stellate ganglion. o The duct continues superiorly running between B. ABDOMINAL SYMPATHETIC TRUNK the aorta and the azygous vein, and anterior to the vertebral column PILOY, ANG, CALIAG Page 4 of 10  PINES CITY COLLEGES 0P.01 F.08 Trans Title SYSTEM AND THE THORACIC DUCT THE AZYGOS Lecturer | Date The thoracic duct ascends: o Through the aortic hiatus of the diaphragm (on the right side of the descending aorta), entering the posterior mediastinum, still to the right of the vertebral column It courses posterior to the esophagus: o At the 7th thoracic vertebral level Gradually crosses the median plane behind the esophagus and reaches the left border of esophagus at level of lower border of the body of 4th thoracic vertebra (sternal angle) Turns upward along the left edge of esophagus to enter the root of the neck o Bends laterally behind the carotid sheath and in front of the vertebral vessels As the thoracic duct continues upward o It runs behind the aorta and to the left of the Figure 11. Diagram showing the regions of the body drained by esophagus the right lymphatic duct and the left lymphatic duct or thoracic o Ascending 2 to 3 cm above the clavicle duct. Turns downward in front of the left phrenic nerve and crosses the subclavian artery to enter the beginning of left brachiocephalic vein A.4 DIVISIONS OF THE THORACIC DUCT In the superior mediastinum, it passes behind the following Cervical portion (LevelI): o Located in the Posterior mediastinum o Left common carotid artery o Vagus nerve Thoracic portion o Internal jugular vein o Ascends the diaphragm and enters the Aortic It then descends to empty: orifice to (7. o into the junction of the left subclavian and IJV o Roam of the aortic orifice to C7 Abdominal portion A.3 ANATOMICAL RELATIONS o Leaves the cisterna passing through the aortic orifice of the diaphragm A. IN RELATION TO THE LEFT SIDE At the root of the neck, thoracic duct receives the: A.5 CISTERNA CHYLI o Left Jugular vein Expanded portion of the proximal thoracic duct located o Subclavian vein in the abdominal vertebral wall (L1-L2 vertebral level) o Broncho-mediastinal lymph nodes/ trunks Confluence of the lymphatic tissues, trunks, or vessels that Although they may drain directly into adjacent large drains the intestines and lower portions of the body veins. Elongated lymph sac which lies below the diaphragm in Thoracic duct conveys to the blood all lymph, from the: front of the first two lumbar vertebrae and on the right side o Lower limbs of the aorta. o Pelvic cavity Receives the intestinal trunk, the right and left lumbar o Abdominal cavity trunks, and some small lymph vessels that descend from Left: the lower part of the thorax. o Side of the thorax The pre- and lateral aortic nodes will drain into the o Side of the head and neck cisterna chyli. o Arm B. IN RELATION TO THE RIGHT SIDE A.6 OTHER FEATURES OF THE THORACIC DUCT Right jugular, subclavian, and broncho-mediastinal This is also known as the Van Horne’s canal lymph nodes/ trunks: drain the right side of the head and Largest lymphatic vessel of the lymphatic system of the neck, upper limbs, and thorax respectively. body. Join to form the RIGHT LYMPHATIC DUCT o 18 inches (around the same length as the This common duct if present is about 0.5 In. (1.3 cm spinal cord) Long) and opens into the beginning of the Right o Upper end of cisterna chyli Brachiocephalic vein Alternatively, the trunks open independently into the Elongated sac under the right crus of the diaphragm GREAT VEINS at the root of Neck It extends from the: o 12th thoracic vertebra to the root of the neck Formed from the abdominal confluence of the o Left and right lumbar lymph trunks o Left and right intestinal lymph trunks - Between the T12 and the L2 o If the confluence of the lymph trunk is SACCULAR, we call that the cisterna chyli Note: The action of breathing helps chyle, flow up the thoracic duct. The duct contains: o Smooth muscles - within its walls PILOY, ANG, CALIAG Page 5 of 10  PINES CITY COLLEGES 0P.01 F.08 Trans Title SYSTEM AND THE THORACIC DUCT THE AZYGOS Lecturer | Date o Interval valves – prevents backflow of lymph o Spleen The thoracic duct crosses the diaphragm at the aortic o Liver hiatus o Intestines The fluid drains at the level of venous angle or between The thoracic duct, just like the azygos vein, is very variable the left subclavian vein and the left internal jugular vein Anatomic variants: where it re- enters the systemic venous circulation. o Two thoracic ducts may be present It is often dilated or enlarged at its terminal segment Landmarks: Bicuspid valve located at the junction of the thoracic o Locate the vertebral column, anterior to it duct with the draining vein which prevents backflow of (ligaments) is the thoracic duct venous blood into the lymphatic system o Sibson’s fascia DRAINAGE: o The thoracic duct drains lymph from the Left to A.9 ANATOMICAL VARIATIONS OF THE THORACIC DUCT right descending thoracic lymph trunk Originating from the lower 6th intercostal spaces The duct also receives lymph from the ICS 1 to 5 via the upper intercostal lymph trunks Additional Tributaries include: o Mediastinal lymph trunks o Left jugular trunk o Left broncho-mediastinal trunk o Left subclavian trunk A.7 FUNCTIONS OF THE THORACIC DUCT Transport lymph back to the circulatory system Interstitial Fluid is collected by lymph capillaries from the interstitial space Lymph will then move through the lymphatic vessels to the lymph nodes Figure 13. Anatomical Variation Lymphatic vessels merge to create the lymphatic ducts, which drain into the venous system Delivers an estimated of o 60-190 ml/hour of lymph (the normal fluid volume) o Estimated of 1.38 ml/kg/hour of lymph to the venous system o 2 to 4 liters of lymph/day Figure 14. Anatomical Variation of Cisterna Chyli The typical anatomy described is present in only 50% of Figure 12. Thoracic duct, including the cisterna chyli at the level of the 2nd lumbar vertebra individuals of the thoracic duct. There are many anatomic variations as cisterna chyli is A.8 TRIBUTARIES OF THE THORACIC DUCT present in about half of individuals: May come from the following structures: o When embryologic lymphatic trunks converge o Lower limbs above the 12th thoracic vertebral level, the o Pelvis & viscera cisterna chyli is generally absent. But there o Kidneys may be dilation of lower lumbar trunks. o Suprarenal o In the embryo, portions of a bilateral system of o Deep abdominal wall lymphatics lymphatic trunks anastomose and develop o Left lumbar passes behind the aorta while portions atrophied. o Stomach PILOY, ANG, CALIAG Page 6 of 10  PINES CITY COLLEGES 0P.01 F.08 Trans Title SYSTEM AND THE THORACIC DUCT THE AZYGOS Lecturer | Date o Failure of the typical pattern leads to anatomic variations of the thoracic duct. VARIATIONS DESCRIPTION Common variation Caused by Bifid lower aspect of the embryonic right lower trunk and left lymphatic trunks failing to fuse Replaced by a plexus of Lower thoracic duct lymphatic vessels and replaced forming a single duct higher in the mediastinum Complete bilateral Two Rare Variations thoracic ducts Termination of the duct into the azygous system Figure 15. The Right and Left Lymphatic Ducts VARIATION OF TERMINATION OCCURRENCY VII. CLINICAL CORRELATION SIDE A. VIRCHOW’S NODE / TROISER’S SIGN LEFT SIDE TERMINATION Majority of cases Presence of palpable lymph node at the LEFT RIGHT SIDE TERMINATION 2%-3% of cases supraclavicular region BILATERALLY Up to 1.5% Present manifestation of patients diagnosed with gastric cancer (most common) TERMINATION SITES OCCURRENCY Metastatic spread of cancer via the thoracic duct may Internal jugular vein lead into an enlargement of the left supraclavicular node, Subclavian vein, or Over 95% of cases which is known as the Virchow's Node, leading to an In the angle between the two appreciable mass that can be recognized clinically called the Troiser’s Sign External jugular vein Thoracic Duct Involvement Vertebral vein o Any cancer arising on the left side will affect Brachiocephalic the lymph node at the left supraclavicular vein 5% of cases region (Sign of a static spread). Suprascapular vein Transverse cervical vein VARIATION IN NUMBER OF OCCURRENCY TERMINALS SINGLE VESSEL Over 87.5% of cases BILATERAL DUCTS Up to 25% of cases SEVERAL TERMINAL BRANCHES Up to 7% of cases B. RIGHT LYMPHATIC DUCT Formed by the merging trunks which drains the right upper portion of the body (see Figure 7) Smaller than the thoracic duct Joining the right jugular, subclavian, and bronchomediastinal trunks which drains the right side of Figure 16. Virchow’s Node / Troisier's Sign the head and neck, the upper limb, and the right side of the thorax. B. CHYLOTHORAX There is presence of chyle in the pleural space Most of the cases of chylothorax is due to injury to the thoracic portion of the thoracic duct Due to increased pressure within the thoracic duct EXTRAVASATION OF CHYLE (can be thoracic or abdominal, iatrogenic (pneumonectomy) or traumatic – traumas to the neck (specifically the right), aside from blood spurting out, there would also be a milky substance PILOY, ANG, CALIAG Page 7 of 10  PINES CITY COLLEGES 0P.01 F.08 Trans Title SYSTEM AND THE THORACIC DUCT THE AZYGOS Lecturer | Date Commonly located at the left side especially if there is D. CONGENITAL ANOMALIES injury on the thoracic duct Azygos fissure Agenesis of the azygos vein Aortic nipple Azygos continuation of IVC and partial venous return D.1 ABSENCE OF AZYGOS VEINS Congenital absence of the azygos vein is rare. CT scan may demonstrate absence of the azygos vein, with consequent enlargement of the hemiazygos, accessory hemiazygos, and left superior intercostal veins. D.2 AZYGOS LOBE Incomplete medial migration of the right posterior