Anatomy of Heart

1. Valves of the heart
• Provides unidirectional flow of blood.
• 2 pairs: atrioventricular valve & semilunar
valve
• A.V. valve:
• Right a.v. valve is known as tricuspid valve
because of 3 cusps(anterior, posterior &
septal)
• Left a.v. valve(mitral) is known as bicuspid
valve due to 2 cusps.(anterior/aortic
&posterior)
• Both valves have following components:
1.Fibrous ringor annulus to which cusp attach
2.Leaflet or cusp
3.Chorda tendinae-connects upper free margin
of the cusp to papillry muscle
4.Papillary muscle-whose contraction makes the
valve competant.

2. Semilunar valve
• Aortic & pulmonary valve are
semilunar valves-cusps are
semilunar in shape.
• Each valve has 3 cusps which
are attached to the fibrous
scallop of the orifice by convex
margin.
• Free margin shows fibrous
nodule (nodule of Arantius ) at
the centre with 2 thin lunule at
the side.
• Opposite the cusp, vessel walls
are dilated to form aortic &
pulmonary sinuses.
• Applied anatomy: stenosis,
valvar incompetence leading
to regurgitation (murmur)

3. Skeleton of the heart
• It consists of 4 fibrous rings around
A.v. orifice, pulmonary & aortic orifices
• Pulmonary & aortic rings are
• connected by fibrous septum
called tendon of infundibulum.
• Right & left A.V. rings are united by
trigonum fibrosum dextrum.
• Aortic & left A.V. rings are connected
by trigonum fibrosum sinistrum.
• These interconnected fibrous rings
provide attachment to cardiac
muscle & supports the valve
• It disturbs the continuity between atrial &
ventricular muscle. So impulses are
propagated through conductng system of
the heart

4. Conducting system of the Heart
• They are the specialized
myocytes for initiation &
conduction of cardiac
impulses. It includes:
• Sinuatrial node(S.A node)
• Atrioventricular Bundle & its
2 limbs
• Subendocardial plexus of
purkinje fibers.
• Heart beat is myogenic.

5. Conducting system of the Heart

6. Blood supply of the heart
• Heart is supplied by 2 coronary arteries-
rt.&lt. arising from ascending aorta.
• coronary is derived from the word
`crown’which encircles the base of ventricle
as a crown
• Each coronary artery is vasvasorum
• Right coronary artery:
• Arises from ant. Aortic sinus & passes
forward to the right betn pulmonary trunk
& rt auricle.
• Then runs in the rt. Coronary sulcus to the
junction of rt. & inferior border of the
heart.
• It winds around the inferior border to reach
diaphragmatic surface of the heart. Here it
runs backward & to the left to reach
posterior iv groove & terminates
anastomosing with left coronary artery.

7. Blood supply of the heart

8. Contd..
• Left coronary artery: Larger than right coronary artery.
• Arises from left posterior aortic sinus .
• Pecularities:
• Sometimes left coronary artery may arise from pulmonary
trunk.
• Sympathetic stimulation constricts the epicardial artery & dilate
intramuscular arteries.
• It is the only vessel where blood flows in diastole.
• Cardiac & extracardiac anastomosis
• 85% of Inter- atrial anastomosis takes place in precapillary level
&15% in capillary level. So they are not typical end arteries but
functionally behave like end arteries.

9. Inter-atrial anastomosis
• Sites of anastomosis are:
• Kugel’s artery: artterial branch of both coronary arteries
communicates at ant. atrial wall.
• Anastomosis between anterior & posterior interventricular artery
near to the apex.
• Annulus of Vieussens- anastomosis betn rt. & left conal artery
around the infundibulum.
• In the intervenricular septum
• Near the crux of the heart
• Coronary perdominance:
• Most case right coronary predominance where posterior
interventricular artery is derived from right coronary artery(70%).
• Minority of population has left coronary predominance-from left
coronary artery.
• In balanced pattern branches of both run in or near the sulcus.

10. Venous drainage of the heart
• Great cardiac vein
• Middle cardiac vein
• Small cardiac vein
• Oblique vein of left atrium(of
Marshal)
• Left marginal vein
• Anterior cardiac vein
• Venae cordis
minimae(Thebesian vein)
• All veins excep last two drain
into coronary sinus which
open into rt. Atrium.

11. Contd..

12. Nerve supply of the heart
• Derived from cardiac plexus formed by
sympathetic (T1-T4/T5) &
parasympathetic(vagus) nerves.
• Cardiac plexus suprficial-below the arch of
aorta
deep-infront of bifurcation
of trachea

13. Applied anatomy
• Common cause of death in developed
countries-ischaemic heart disease
• Sudden obstruction of major branch of
coronary vessels lesd to myocrdial infarction.
• Common branches for occlusion are:
• Anterior interventricular artery
• Rt. coronary artery
• Circuflex branch of left coronary artery