The Heart

山东大学医学院 解剖教研室李振华

Position Lies within the pericardi

um in middle mediastinum

Behind the body of sternum and coastal cartilages 2 to 6

In front of thoracic vertebrae 5 to 8

A third of it lies to the right of median plan and 2/3 to the left

External characteristics －a hollow muscular organ, pyramidal in shape , somewhat larger than a closed fist; consists of four chanbers (right and left atria, right and left ventricles)

Cardiac apex is formed by left ventricle and is directed downwards and forwards to the left. It lies at the level of the fifth left intercostal space, 1~2cm medial to the left midclavicular line (9cm from the midline)

Cardiac base is formed by the left atrium and to a small extent by the right atrium. It faces backward, upward and to the right

Two surface Sternocostal surface is

formed mainly by the right atrium and right ventricle, and a lesser portion of its left is formed by the left auricle and ventricle. It is directed forwards and upwards

Diaphragmatic surface is formed the ventricles － chiefly the left ventricle, directed backwards and downwards, and rest upon the central tendon of the diaphragm

Three borders Right border － vertical, i

s formed entirely by right atrium

Left border － round, is mainly formed by the left ventricle and partly by the left auricle

Inferior border － horizontal, is formed by the right ventricle and cardiac apex

Four grooves Coronary sulcus 冠状沟 (circular sulcu

s) which marks the division between atria and ventricles, contains the trunks of the coronary vessels and completely encircles the heart

Interatrial sulcus 房间沟－ separates the two atria and is hidden by pulmonary trunk and aorta in front

Interventricular grooves 室间沟－ anterior and posterior, mark the division between ventricles (which separates the RV from the LV), the two grooves extend from the base of the ventricular potion to a notch called: the cardiac apical incisure 心尖切迹

Atrioventricular crux 房室交点－ a junction of the posterior interventricular groove and coronary sulcus

Chambers of the heart

Right atrium 右心房 (RA)

Three inlets Orifice of superior vena cava 上腔静脉口

－ returns blood to the heart from the upper half of the body

Orifice of inferior vena cava 下腔静脉口 － returns blood to the heart from the lower half of the body

Orifice of coronar sinus 冠状窦口 －returns blood to the heart from the cardiac muscle

One outle － right atrioventricular orifice 右房室口

Crista terminalis 界嵴 －vertical ridge thatjfrom superior vena cave to inferior vena cave

Sulcus terminalis 界沟 －groove on exterior of heart that corresponds to crista terminalis

Two parts － separated externally by sulcus terminalis and internally by the crista terminalis

Atrium proper 固有心房 In front of the ridge Pectinate muscles in wall Right auricle 右心耳－ a small c

onical muscular pouch, projects to the left from the root of superior vena cava, pectinate muscles in wall

Sinus venarum cavarum 腔静脉窦 Lies posterior to the ridge Smooth walls Fossa ovalis 卵圆窝－ an oval

depression, a remnant of the fetal foramen ovale, on the lower part of interatrial septum, the most common location of atrial septal defects (ASD)

Limbus fossae ovalis 卵圆窝缘 – prominent margin of fossa ovalis

Torus aortious 主动脉隆凸

Right ventricle (RV) 右心室 Receives deoxygenated blood fro

m right atrium through right atrioventricular orifice

One inlet － right artrioventricular orifice 右房室口

One outlet － orifice of pulmonary trunk 肺动脉口

Two parts － divided by the supraventricular crest 室上嵴 , a muscular ridge between right atrioventricular orifice and orifice of pulmonary trunk

Inflow tract － rough walls Trabeculae carneae 肉柱 －

irregularly arranged bundles of myocardium

Septomarginal trabecula 隔缘肉柱－ extends from interventricular septum to base of anterior papillary muscle, contains right bundle branch

Papillary muscles 乳头肌－ conical-shaped , anterior, posterior and septal

Out flow tract Conus arteriosus 动脉圆锥 c

one-shaped, smooth area leading upward to orifice of pulmonary trunk

Pumps blood through pulmonary orifice to pulmonary trunk

Left atrium (LA) 左心房

Left auricle 左心耳－ projecting to the right, pectinate muscles in wall

Four inlets － four orifices of pulmonary veins 肺静脉口 open through the posterior wall

One outlet － left atrioventricular orifice 左房室口 , blood leaves through left atrioventricular orifice to left ventricle

Left ventricle (LV) 左心室 Has wall three times thicker tha

n that of right ventricle One inlet － left atrioventricul

ar orifice 左房室口 One outlet － aortic orifice

主动脉口 Two parts － divided by anterior

cusps of mitral valve Inflow tract － rough walls Outflow tract – aortic vestibule

主动脉前庭 , smooth area leading to aortic orifice

Valves Tricuspid valve 三尖瓣 Guards right atrioventricular orific

e Three triangular cusps: anterior, p

osterior and septal, the base of cusps are attached to fibrous ring surrounding the atrioventricular orifice

Chordae tendineae 腱索－ fine, white, connective tissue cords, attach margin of cusps to papillary muscles 乳头肌

Mitral valve 二尖瓣 Guards left atrioventricular orifi

ce Two triangular cusps － anteri

or and posterior with commissural cusps between them (posteromedial and anterolateral commissures)

Similar structures to those of right

Similar functions for right and left atriventricular valves Open during diastole to allow blood to enter ventricles from atri

a Closed during systole to prevent regurgitation of blood into atri

a

Valve of pulmonary trunk 肺动脉瓣

Guards the orifice of pulmonary trunk

Has three semilunar cusps – each with free border that has central nodules of semilunar valve 半月瓣小结

Aorti vavle 主动脉瓣 Guards the aortic orifice Three semilunar cusps (right,

left and post) Three aortic sinuses – bulges

in aortic wall at level of valve that correspond to cusps

Right － contains opening of right coronary artery

Left － contains opening of left coronary artery

Posterior － no opening

Similar functions for pulmonary and aortic valves

Opening during systole, with cusps pressed toward wall of vessel as blood is forced upward

Closed during diastole Ventricular pressure drops

in diastole Floating together of valve

cusps, with free borders meeting, thus closing the valve

Structure of the heartWalls of heart Endocardium 心内膜－ inne

r coat of the heart wall, and continuous with the valve flaps

Myocardium 心肌 Arranged spirally Attached to fibrous rings

surrouding the four orifices of heart

Epicardium 心外膜－ serous membrane (visceral pericardium)

Interatrial septum 房间隔 Located between right and

left atria Contains fossa ovalis and li

mbusInterventricular septum

室间隔 Located between right and

left ventricles Has upper membranous pa

rt Has thick lower muscular p

art

Fibrous skeleton 纤维骨骼 Fibrous rings that surround t

he atrioventricular, pulmonary, and aortic orifices

Left and right fibrous trigons

Conduction system of heart 心传导系 Consists of specialized m

yocardial cells

Sinuatrial node 窦房结(SA node)

Called the pacemaker cell (P cell)

Located at the junction of right atrium and superior vena cava, upper part of the sulcus terminalis, under the epicardium

Atrioventricular node 房室结 (AV node)

Located in the lower part of interatrial septum just above the orifice of coronary sinus, under the endocardium

Lower part related to membranous part of interventricular septum

Atrioventricular bundle 房室束 (AV bundle)

Passes forward through right fibrous trigon to reach inferior border of membranous part

Divides into right and left bundle branches at upper border of muscular part of interventricular septum

Right and left bundle branches 左、右束支

Right bundle branch － passes down on right side of interventricular septum to reach the septomarginal trabecular and into the base of anterior papillary muscle. Here it becomes continuous with the fibers of Purkinje fibres

Left bundle branch － passes down on left side of interventricular septum beneath the endocardium. It usually divides into two branches, which eventually become continuous with the Purkinje fibers

Purkinje fibers 普肯野氏纤维 － continuous with myocardium

Arterial supplyLeft coronary artery 左冠状动

脉 Arises from left aortic sinus Runs between pulmonary trunk and left a

uricle into coronary sulcus Branches

Anterior interventricular branch 前室间支－ travels downward in anterior interventricular groove around inferior margin of heart to posterior interventricular groove

Circumflex branch 旋支－ travels to left in coronary sulcus to posterior aspect

Distribution － supplies left atrium and ventricle, lesser portion of anterior wall of right ventricle, and anterior 2/3 of interventricular septum

Right coronary artery 右冠状动脉 Arises from the right aortic sinus Runs forward between right auricle a

nd pulmonary trunk into coronary sulcus

Branches Right marginal branch 右缘支 －

travels along inferior bord Posteror interventricular branch

后室间支－ travels downward in posterior interventricular groove, it anastomosises near the apex with the anteriorinterventricular branch of the left coronary artery

Distribution: supplies right atrium and ventricle, posterior 1/3 of interventricular septum, posterior wall of left ventricle, the sinuatrial node and atrioventricular node

Venous drainage

Coronary sinus 冠状窦 Located in posterior part o

f coronary sinus Carries most of venous bl

ood from myocardium to right atrium

Tributaries Great cardiac vein 心大静脉 Middle cardiac vein 心中静

脉 Small cardiac vein 心小静脉

Anterior cardiac veins 心前静脉－ 3~4 small vessels, drain into right atrium

Smallest cardiac veins 心最小静脉－ drain into all chambers, mainly atria

Pericardium 心包Fibrous pericardium 纤维心包 Attached to central tendon of diap

hragm inferiorly Blends with outer coat of great ve

ssels superiorly

Serous pericardium 浆膜心包 Visceral pericardium (epicardium) Parietal pericardium

Pericardial cavity 心包腔 Potential space between visceral

and parietal pericardium Contains film of pericardium fluid

Pericardium sinus Transverse sinus of pericardium 心包横窦－ posterior to as

cending aorta and pulmonary trunk, anterior to superior vena cava and left atrium.

Oblique sinus of pericardium 心包斜窦－ cul-de-sac , posterior to heart, bounded by pulmonary veins on either side

Surface markings of heart Right border － corresponds t

o a line running from the upper border of right third costal cartilage ±1.2cm from the margin of sternum, downwards to sixth sternocostal joint

Apex － in the fifth left intercostal space 7~9cm from the midline

Left border － represented by a line running from apex upwards and medially to a point on lower border of left second costal cartilage ±1.2cm from sternal margin

Lower border － represented by a line joint the lower end of right border to apex

Dissection of the heart