PERICARDIUM and HEART Dr. Milton M. Sholley

SELF­STUDY RESOURCES

Essential Clinical Anatomy 3 rd Ed. (ECA): pp.82­103

Syllabus: 16 pages (Page 16 lists corresponding figures for Grant's Atlas 11 th & 12 th Eds.)

Head to Toe Questions in Gross Anatomy: Continue questions #216­253 and #465­541.

STRUCTURES TO BE OBSERVED

Pericardium: ­Visceral and parietal layers ­Fibrous pericardium ­Transverse and oblique pericardial sinuses

Heart: ­Base and apex ­Surfaces: diaphragmatic, sternocostal, right (margin), left (margin) ­Margins: right (acute), inferior, left (obtuse) ­Right atrium: crista terminalis, pectinate muscles, inferior and superior vena

caval openings, ostium of the coronary sinus, fossa ovalis ­Right ventricle: trabeculae carneae, septomarginal band, papillary muscles,

chordae tendineae, tricuspid valve, pulmonary valve, nodules and lunules, conus arteriosus

­Left atrium: pectinate muscles, fossa ovalis, openings of pulmonary veins ­Left ventricle: left atrioventricular orifice, aortic vestibule, interventricular

septum with membranous and muscular parts, bicuspid valve, papillary muscles, chordae tendineae, aortic valve, cusps, nodules and lunules, left and right aortic sinuses, left and right coronary artery ostia

Blood vessels: ­Right coronary artery: sinuatrial nodal artery, conus artery, right marginal artery,

atrioventricular nodal artery (difficult to find), posterior interventricular artery

­Left coronary artery: anterior interventricular (LAD) artery, circumflex artery, diagonal arteries, posterior left ventricular artery, left marginal artery

­Great, middle and small cardiac veins, coronary sinus ostium in right atrium Conducting system (cannot be visualized, but locate by relationships):

­Locations of sinuatrial (SA) node, atrioventricular (AV) node, atrioventricular bundle (divides into left & right bundle branches)

Fibrous skeleton (difficult to visualize; find by palpation and relationships): ­Four fibrous rings (annuli fibrosi) for four heart valves; opening for

atrioventricular bundle; fibrous trigone

LECTURE OUTLINE

I. General remarks:

The pericardium is a double walled sac that encloses the heart. The pericardium with its enclosed heart essentially fills the compartment of the thorax known as the middle mediastinum.

The heart is a muscular pump that has two halves: a right half, which receives venous blood from the body (excluding the lungs) and pumps it to the lungs where gaseous exchange occurs, and a left half, which receives oxygenated blood from the lungs and pumps it to the rest of the body. This movement of blood from body to right heart, to lungs, to left heart, to body in endless fashion, is termed circulation. The right heart includes two chambers, a right atrium which receives blood and a right ventricle which pumps it out. Similarly the left heart includes two chambers, a left atrium which receives blood and a left ventricle which pumps it out. The heart has its own coronary arteries and cardiac veins, an intrinsic conduction system (made­up of modified cardiac muscle) to propagate the heartbeat, and superimposed extrinsic controls by the autonomic nervous system. There are two valves associated with each ventricle and the cusps of the valves are anchored to the fibrous skeleton of the heart. The position of the heart changes with posture. The sound produced by the closing of the valves can be heard on the anterior chest wall in precise locations. Fetal circulation changes to adult circulation at the time of birth, when certain structural changes occur.

Right auricle

Left atrium

Right auricle

Right ventricle

Right ventricle

Left ventricle

Opened Chambers of the

Human Heart

II. The Pericardial Sac

The pericardium is composed of two layers of serous membranes, parietal and visceral, separated by a potential space, the pericardial cavity, in which a thin layer of serous fluid serving as a lubricant is present.

A. The parietal layer of serous membrane is strengthened by its fusion to an underlying fibrous tissue layer called the fibrous pericardium, which has the appearance of a cone­shaped bag. The inferior surface of the fibrous pericardium is firmly attached to the diaphragm and on the right side, is pierced by the inferior vena cava. On its superior surface the fibrous pericardium is pierced from right to left, by the superior vena cava, ascending aorta and pulmonary trunk. Below these three vessels and posteriorly, it is pierced by right and left superior and inferior pulmonary veins. At the points of attachments of these eight vessels, the fibrous pericardium blends with the connective tissue of the vessels.

Cut edge of fused fibrous (outside) + parietal (inside)

layers of pericardium

Note the opened Pericardial Sac

The visceral layer of pericardium (or epicardium) tightly adheres to the surface of the heart

The pericardial sac is the space between the parietal and visceral layers of the serous pericardium. The sac normally contains only a thin layer of serous fluid, but inflammation of the sac (pericarditis) can cause a large increase in the volume of fluid.

Grant’s Atlas, 12 th Ed., Fig. 1.21, p. 25

The parietal layer of pericardium tightly adheres to the inside of the fibrous pericardium

The fibrous layer of pericardium is thick and makes the pericardial sac tough and inflexible

B. The visceral layer of serous pericardium is continuous with the serous parietal layer, and the pericardial cavity or space lies between the two. Since the 6 veins (4 pulmonary, 2 vena cava) have a common development at one end of the heart tube, they are enclosed in a common sleeve of serous membrane, which becomes the oblique pericardial sinus. Similarly the 2 arteries have a common development at the opposite end of the heart tube, and are therefore also enclosed in a common sleeve of the serous membrane. Since the proximal ends of these arteries lie in the pericardial cavity they are covered by the visceral layer of the

serous pericardium, forming a transverse pericardial sinus of the pericardial cavity. When the heart tube becomes U­shaped, the arterial and venous ends come close together, but retain their original sleeves of serous membrane.

Grant’s Atlas, 12 th Ed., Fig. 1.44B, p. 51

Transverse pericardial sinus

Pulmonary trunk

Left superior pulmonary vein

Left inferior pulmonary vein

The base of the heart sits here, forming the opposite (anterior) wall of the oblique pericardial sinus. The line of junction between the parietal and visceral layers of serous pericardium surrounds the six great veins and creates a cul­de­ sac known as the oblique pericardial sinus.

Right superior pulmonary vein

Right inferior pulmonary vein

Inferior vena cava

Superior vena cava

Oblique and Transverse Pericardial Sinuses

Posterior wall of opened pericardial sac – heart removed

Grant’s Atlas, 12 th Ed., Fig. 1.44A, p. 50

Pulmonary trunk

Left superior pulmonary vein

Left inferior pulmonary vein

Right superior pulmonary vein

Right inferior pulmonary vein

Inferior vena cava

Superior vena cava Transverse pericardial sinus

The base of the heart, covered by visceral pericardium, forms the anterior wall of the oblique pericardial sinus. The line of junction between the parietal and visceral layers of serous pericardium surrounds the six great veins and creates a cul­de­ sac known as the oblique pericardial sinus.

Posterior view of heart

Oblique and Transverse Pericardial Sinuses

The visceral layer of serous membrane with underlying fat and blood vessels forms the outermost layer of the heart wall called epicardium. The other two layers of the wall of the heart are the thick muscular middle layer, or myocardium, and the thin inner layer, or endocardium, formed by an endothelial lining.

III. External form of the heart

In a general way, the heart resembles a slightly flattened cone, having a base and apex, with four intervening surfaces (two of which are sometimes called margins).

A. The wide base of the heart faces posteriorly in the midline of the body. All 6 veins enter the base and serve to anchor the heart. The oblique pericardial sinus is located between the veins at the base of the heart.

B. The blunted apex, or opposite end, points forward and to the left and is approximately 3.5 inches from the midline at the level of the left 4th or 5th intercostal space, and can be felt pulsating in the living individual.

C. The diaphragmatic (or inferior) surface rests on the diaphragm and consists of the left ventricle and part of the right ventricle, up to the apex. Present on this surface are the coronary sinus and posterior interventricular sulcus containing an artery and vein.

D. The sternocostal surface faces anteriorly. The right ventricle occupies most of the sternocostal surface but a small part of the left ventricle also contributes to this surface. The right and left atria are seen superiorly, separated from the ventricles by a coronary sulcus in which blood vessels are present. From the left side of the coronary sulcus, an anterior interventricular sulcus extends to the apex and continues across the apex to become the posterior interventricular sulcus, which runs on the posterior surface of the heart and then intersects the coronary sulcus again. It marks the position of the interventricular septum, and has overlying blood vessels.

E. The right surface (sometimes called the acute margin) and the left surface (sometimes called the obtuse margin) face the right and left lungs, respectively. The right surface consists of right atrium whereas the left surface consists of left ventricle.

F. The right surface is continuous with the inferior margin, where it truly becomes a fairly sharp edge or acute margin.

G. The margins or borders of the heart are poorly defined, but can be seen radiographically as the cardiovascular shadow.

IV. Blood Supply of the Heart.

The two coronary arteries (right and left) originating in the aortic sinuses supply blood to heart tissues. The cardiac veins collect the blood, most which is returned to the right atrium via the coronary sinus. An important concept regarding the positioning of the major arterial and venous vessels is that they are located in the various sulci on the surface of the heart, including the atrioventricular (or coronary sulcus), the anterior interventricular sulcus, and the posterior interventricular sulcus.

A. The right coronary artery, the main trunk of which lies in the right side of the coronary sulcus, supplies the right atrium, anterior and posterior parts of the right ventricle, posterior parts of the left ventricle, interatrial and interventricular septa, and usually the sinuatrial (SA) and atrioventricular (AV) nodes. The named branches of the right coronary artery include the sinuatrial nodal artery, conus artery, right marginal artery, atrioventricular nodal artery, and the posterior interventricular artery (which lies in the posterior interventricular sulcus). Alternatively, the posterior interventricular artery may arise from the circumflex branch of the left coronary artery. When the posterior interventricular artery arises from the left coronary, the arterial circulation of the heart is said to be “left dominant”, as opposed to the more usual “right dominant” circulation.

B. The left coronary artery supplies most of the left atrium and left ventricle, the anterior part of the interventricular septum, and the conus arteriosus. The atrioventricular bundle and its branches (parts of the conducting system of the heart associated with the interventricular septum) get their blood from this source. The left coronary artery, soon after it originates from the left aortic sinus, bifurcates into (1) the anterior interventricular artery (often called left anterior descending artery, or LAD), which descends in the anterior interventricular sulcus, and (2) the circumflex artery, which turns posteriorly in the left side of the coronary sulcus. The branches of the anterior interventricular artery include several diagonal arteries. The branches of the circumflex artery include a large posterior left ventricular artery, a left marginal artery, and sometimes an intermediate artery. Alternatively, either one or both of the latter two arteries may arise from the anterior interventricular artery. Also, either one or both of the nodal arteries may originate from branches of the left coronary artery instead of

from the right coronary artery. In the clinical literature many more branches are given names, and the ones given here may be known by other names. Variations of the coronary arteries in diameter, length and tissue area perfused are not unusual.

Coronary Arteries

Anterior view

Left coronary artery (main stem)

Right coronary artery

SA nodal branch

Grant’s Atlas, 12 th Ed., Fig. 1.45A, p. 52

Right marginal branch

Circumflex branch

Left anterior descending branch (LAD)

Left marginal branch

Diagonal branch of LAD

Note: LAD is also called the anterior Interventricular branch

Conus branch

Coronary Arteries

Posterior view

Grant’s Atlas, 12 th Ed., Fig. 1.45B, p. 52

Circumflex branch

Posterior interventricular (posterior descending) branch

Crux of heart

AV nodal branch

Note: The crux of the heart is the area of junction of the atrioventricular and posterior interventricular sulci. If the right coronary artery gives off the posterior Interventricular (as here) the pattern is “right dominant”. If the circumflex branch of the left coronary reaches the crux and gives off the posterior interventricular the pattern is”left dominant”. About 60% of hearts are “right dominant”.

C. Cardiac veins are usually located in the sulci parallel to the coronary arteries. The great cardiac vein accompanies the anterior interventricular and circumflex arteries and ends as the large coronary sinus, which opens into the right atrium.

The middle cardiac vein (accompanying the posterior interventricular artery) and the small cardiac vein (accompanying the right marginal artery) reach the coronary sulcus and also empty into the coronary sinus.

There are smaller veins which do not empty via the coronary sinus. These include several anterior cardiac veins which open directly into the right atrium. There are also veins called the least cardiac veins (or Thebesian veins), which are located in the substance of the myocardium and drain directly into any adjacent heart chamber (atria or ventricles). Careful examination of the endocardial surface is required to see the ostia of the least cardiac veins, and the veins themselves are rarely observable grossly.

Anterior view Grant’s Atlas, 12 th Ed., Fig. 1.46A, p. 53

Cardiac veins

Great cardiac vein

Middle cardiac vein

Oblique vein of left atrium

Anterior cardiac veins

Small cardiac vein

Coronary sinus

Posterior view

Grant’s Atlas, 12 th Ed., Fig. 1.46D, p. 53

Cardiac veins

Great cardiac vein

Middle cardiac vein

Oblique vein of left atrium

Small cardiac vein

Coronary sinus Left marginal vein

Left posterior ventricular vein

V. The Internal Anatomy of the Heart

The heart is composed of right and left halves, separated by common interatrial and interventricular septi. Each half is composed of two chambers, an atrium and ventricle separated by an atrioventricular valve. The structure of each of the four chambers follows:

A. The right atrium receives blood from the superior vena cava into its upper posterior corner, and from the inferior vena cava and coronary sinus into its lower posterior corner. From the atrium, the blood is emptied into the right ventricle through the right atrioventricular ostium that faces forward and medially, and is guarded by the right atrioventricular (or tricuspid) valve.

The right atrium consists of a posterior half derived from the primitive vein or sinus venosus and an anterior half derived from the primitive atrium of the embryonic heart. The part derived from the sinus venosus is smooth­walled, whereas that derived from the embryonic atrium is rough­walled, due to the underlying bands of myocardium known as pectinate muscles. A smooth­

Right Atrium Opened

Grant’s Atlas, 12 th Ed., Figs. 1.49 A&B, p. 56

Crista terminalis

Right atrioventricular orifice

Pectinate muscles (rough part of wall)

Valve of IVC IVC

SVC

Fossa ovalis

Orifice of coronary sinus

surfaced muscular ridge or crista terminalis demarcates the two derivatives. Past the crista terminalis, the pecinate muscles fan out into the anterior half of the chamber , which is the auricle.

The interatrial septum is smooth­walled with a depression called the fossa ovalis, which in the fetus is an opening (foramen ovale) that communicates with the left atrium and allows venous blood to pass from the right to the left atrium. The fossa ovalis lies just above the orifice of the inferior vena cava.

A number of small openings, the foramina of the least cardiac veins are scattered about the wall of the right atrium, and also on the walls of the other three chambers.

B. The right ventricle receives blood from the right atrium. In cross section, the cavity is C­shaped. Blood flows into the lower half of the C where the wall of the ventricle is rough due to the presence of muscular trabeculae carneae. These contract and eject the blood into the upper half of the C, or conus arteriosus, where the wall is smooth. From the conus arteriosus or infundibulum (funnel­ shaped) the blood flows to the pulmonary trunk through the pulmonary orifice.

The trabeculae carnae form muscular ridges, bridges and nipple­like projections called papillary muscles. The muscular ridges are numerous and are scattered mostly on the posterior wall. One of the trabeculae carnae usually forms a bridge between the interventricular wall and the anterior papillary muscle and is called the septomarginal trabecula (or moderator band). It carries conduction fibers to the papillary muscles. There are usually three sets of papillary

Grant’s Atlas, 12 th Ed., Figs. 1.50 A, p. 57

Right Ventricle Opened

Moderator band

Anterior papillary muscle

Septal cusp

Posterior cusp

Posterior papillary muscle

Anterior cusp

Septal papillary muscles Conus arteriosus

Chordae tendineae

Orifice of pulmonary valve

muscles, anterior, posterior and septal, the largest and most constant being the anterior papillary muscle and one septal, which may be small or absent. From the apex of each papillary muscle several tendon­like fibrous cords, called chordae tendineae extend to the cusps of the atrioventricular valve. Some of the septal chordae tendineae originate directly from the myocardial wall.

The right atrioventricular valve, also called tricuspid valve, has three cusps or leaflets, located on the anterior, posterior and interventricular septal walls. The three cusps (anterior. posterior, and septal) are attached to the fibrous skeleton of the heart at their bases. They are continuous with each other near their bases but not at their free edges, which spread apart when blood flows into the ventricle, but come together to seal the atrioventricular orifice, when the blood is being expelled to the pulmonary trunk. The free edges are held in the closed configuration by contraction of the papillary muscles and attached chordae tendineae. Eversion of the cusps into the atrium is thereby prevented. These cusps therefore function as one­way valves and prevent regurgitation of blood to the atrium.

The pulmonary valve opens and closes the orifice of the pulmonary trunk. It consists of three cusps, semilunar in shape. The base of each is attached to the wall of the pulmonary trunk, supported by the underlying fibrous skeleton of the heart. The free edge of each cusp has a thickened nodule with a thin walled lunule on either side. The nodules and lunulae of each valvule come together to form a tight seal, due to the back pressure of escaped blood, and open or separate to allow blood to pass into the pulmonary trunk during ventricular contraction. When in the closed position, space is formed between the valvules and pulmonary

trunk called sinuses. In the anatomical position, there is a left, right and anterior cusp of the pulmonary valve.

Grant’s Atlas, 12 th Ed., Figs. 1.53 & 1.54C, p. 60

Aortic and Pulmonary Semilunar Valves

P L

R R

L A

Aortic valve

Pulmonary valve

Superior view

C. The left atrium is similar to the right in having a posterior smooth­walled part into which the pulmonary veins open, and an anterior part with ridges formed by the pectinate muscles on its wall which is continuous with the left auricle. A thin area on the interatrial septum is the remnant of the valvule of the foramen ovale. Probe patency (not functional patency) of the foramen ovale occurs in 20% of adults.

D. The left ventricle receives blood from the left atrium via the left atrioventricular ostium into a conical­shaped cavity having a round cross section. The aortic vestibule is smooth­walled and forms the outflow tract for blood that exits the ventricular chamber via the aortic orifice. The interventricular septum is composed of a large, thick muscular part, the pars muscularis, and a small, thin membranous part, the pars membrancea. Part of this septum can be palpated at a point between the septal cusp and right atrium and the septal part of the left ventricle.

The left atrioventricular ostium opens into the posterior and right side of the upper part of the left ventricle. The two cusps of the left atrioventricular (bicuspid) valve arise from the left atrioventricular fibrous ring that surrounds the ostium.. The left atrioventricular valve is also called the mitral valve because of its fanciful resemblance to a Bishop's miter (a liturgical headdress). The cusps are anterior and posterior in position and correspond to the anterior and posterior

papillary muscles. Chordae tendineae from each papillary muscle attach to one half of each of the cusps.

Left Ventricle Opened

Grant’s Atlas, 12 th Ed., Figs. 1.52A, p. 59

Anterior cusp of mitral valve

Posterior cusp of mitral valve

Anterior papillary muscle Posterior papillary muscle

Chordae tendineae

Trabeculae carneae

Left aortic sinus

Left cusp of aortic valve

Right aortic sinus Right cusp of aortic valve

Orifice of right coronary artery Orifice of left

coronary artery

Posterior (non­coronary) cusp of aortic valve

Posterior sinus of aortic valve

Membranous interventricular septum

The aortic ostium is opened and closed by the aortic valve, which has three semilunar cusps similar in structure to those of the pulmonic valve. The position of the cusps are right, left and posterior and are so named. Unlike the pulmonic valve, however, the right and left aortic sinuses are the sites of origin of the right and left coronary arteries, respectively.

VI. Fibrous Skeleton of the Heart (ECA, Fig. 2­24, p. 91)

Four connected rings of fibrous connective tissue (annuli fibrosi) lie in the same plane and separate the ventricles from the atria. The ventricular myocardium is attached to the lower surfaces of the rings and the atrial myocardium is attached to the upper surfaces. The four fibrous rings also serve as supports to which the bases of the four heart valves are anchored. The cusps attach to the fibrous rings surrounding their respective openings. Interconnected, thickened areas of fusion between the aortic and the left and right atrioventricular rings form the left and right fibrous trigones, respectively. The septum membranaceum blends with the area of fusion between the aortic and right atrioventricular rings. The atrioventricular bundle from the interatrial septum penetrates the fibrous tissue through an orifice located in the right fibrous trigone between the tricuspid and aortic valve rings. In addition to providing attachments for the myocardium and the valve cusps, the fibrous skeleton serves to electrically insulate the atrial myocardium from the ventricular myocardium, and conduction of impulses from the atria to the ventricles is limited to the connection provided by the atrioventricular bundle.

Diagram of the valves of the heart in a superior view with both atria cut away and the aorta and pulmonary trunk cut just above their valves. (From Textbook of Anatomy by W. Henry Hollinshead)

Diagram of the fibrous sketeton of the heart in a superior view with both atria cut away and the aorta and pulmonary trunk cut just above their valves. (From Textbook of Anatomy by W. Henry Hollinshead)

VII. The Conducting System of the Heart

A. The conducting system initiates the heartbeat and regulates the pumping action of the four chambers sequentially and in synchrony.

B. The conducting system is not made­up of nervous tissue; rather it is composed of specialized cardiac muscle fibers that can be identified on histological sections but cannot be visualized gross anatomically in human hearts without special staining techniques. On the other hand, the locations of various parts of the conduction system can be determined by their known positions in relationship to other gross anatomically identifiable structures of the heart.

1. The sinuatrial node (SA node) is a crescent­shaped structure, 5­8 mm in length, which is located in the anterior wall of the right atrium at the junction of the superior vena cava and the sulcus terminalis. The SA node is also known as the pacemaker of the heart. Although the SA node cannot be seen grossly, the SA nodal artery terminates in the node and thus indicates its position.

2. The atrioventricular node (AV node) is located in the wall of the interatrial septum, between the coronary sinus orifice and the attachment of the septal cusp of the tricuspid valve. It is slightly smaller than the SA node, and its inferior surface rests on the fibrous atrioventricular ring (fibrous skeleton of the heart).

Cardiac Conduction System

SA node

AV node

Orifice of coronary sinus

AV bundle

Right bundle branch

Left bundle branch

Orifice of coronary sinus

Crista terminalis

Location of SA node

Location of AV node

Superior vena cava

Interventricular septum

3. The atrioventricular bundle (a fasciculus of conducting fibers, also called bundle of His) is a forward continuation of the AV node. The bundle passes through a hole in the right fibrous trigone, and passes the posterior margin of the membranous part of the interventricular septum, and soon branches into a right and left crus (also called right and left bundle branches). The two cura straddle the upper border of the muscular part of the interventricular septum. Each crus descends toward the apex of the ventricles under the endocardium of the septum. The right crus crosses from the septum to the ventricular wall at the base of the anterior papillary muscle along the septomarginal trabecula. The left crus breaks up into branches leading to several trabeculae carnae. These branches or fasciculi spread out as the subendocardial Purkinje fibers over the ventricular wall and papillary muscles.

VIII. The Heart: Position, Surface Projection, Auscultatory Areas

A. In cadavers, the position of the heart is fairly constant. Its diaphragmatic surface rests on part of the central tendon of the diaphragm and its inferior border corresponds to the level of the xiphisternal junction. One­third of the heart lies to the right of the median plane and extends slightly beyond the edge of the sternum. Two­thirds of the heart lies to the left of the median plane.

B. In the living, the heart shifts in the direction of the pull of gravity and changes position during inhalation and expiration of air. Positional changes are observed according to body type with the heart assuming a more vertical position in tall, slender individuals and a more transverse position in broad stocky individuals and in children.

C. Surface projection of the heart of a cadaver is also fairly constant (Grant's Atlas: 12 th Ed. 1.49, page 44). The right border is formed by the right atrium, the left border by the left ventricle. The large middle portion is formed by the anterior surface of the right ventricle. The plane of the fibrous skeleton is almost vertical, with its right edge inferior and left edge superior in position, and its inferior surface faces anteriorly and to the left. The pulmonic valve is located posterior to the 3rd left sternocostal joint, the aortic valve slightly below the 4th left sternocostal joint. The tricuspid valve is located behind the sternum between the 5th and 6th sternocostal joints. The mitral valve projects to the 4th rib and 4th intercostal space mainly. The apex of the heart projects to the 4th or 5th intercostal space just medial to the midclavicular line.

Auscultation Sites for the 4 Heart Valves

Actual locations of the 4 heart valves projected onto the anterior thoracic wall. The actual locations do not correspond to the sites of auscultation. The sites of auscultation are where the chamber distal (in terms of blood flow) to the valve lies closest to the body surface. P=Pulmonary valve, A=Aortic valve, M=Mitral valve, and T=Tricuspid valve. (From Textbook of Anatomy by W. Henry Hollinshead)

D. The points of auscultation (points at which one places the stethoscope on the chest wall when listening to heart valve sounds) differ from the above­described surface projections of the valves (Grant's Atlas: 12 th Ed. 1.49, page 44). The aortic (A) and pulmonary (P) valves are best heard in the second intercostal spaces, the aortic valve just to the right of the sternum and the pulmonary valve just to the left of the sternum.. The tricuspid (T) valve is best heard over the lower body of the sternum adjacent to the left fifth or sixth costal cartilages. The mitral (M) valve is best heard in the left fifth intercostal space on the midclavicular line (about 3½ inches from the midline).

Figures from Grant's Atlas of Anatomy

(11 th ed.)

1.25A,B&C, page 29 1.21, page 25 1.68A, page 71 1.44B, page 51 and 1.57B, page 63 1.44A, page 50 1.57A, page 63 1.41A, page 46 1.41B, page 47 1.45A&B, page 52 1.43, page 49 1.42, page 48 1.46A&B, page 53 1.49A&B, page 56 1.50A, page 57 and 155C, page 61 1.52A, page 59 and 155A,B&D, page 61 1.53, page 60 1.54, page 60 1.56, page 62 1.39, page 44 1.64A&B, page 68 1.59, page 65 1.61, page 66 1.63, page 67

(12 th ed.)

1.25A&B, page 29 1.21, page 25 1.70A, page 73 1.44B, page 51 and 1.25C&D, page 29 1.44A, page 50 1.59, page 65 1.41A, page 46 1.41C, page 47 1.45A&B, page 52 1.43, page 49 1.42, page 48 1.46A&D, page 53 1.49A&B, page 56 1.50A, page 57 and 157C, page 63 1.52A, page 59 and 157A,B&D, page 63 1.53, page 60 1.54, page 60 1.58, page 64 1.39, page 44 1.66A&B, page 70 1.62, page 67 1.64A, page 68 1.65, page 69