Human Anatomy Vol 1

THOBAX

Trace the circumflex branch of left coronary artery

on the left border of heart into the posterior part of

the sulcus, where it may end by anastomosing with the

right coronary artery or by dipping into the myocardium.

Posilion

Left coronary artery is larger than the right coronary
artery. It arises from the left posterior aortic sinus of
ascending aortic.

Caurse

1 The artery first runs forwards and to the left and
emerges between the'pulmonary trunk and the left
auricle. Here it gives the anterior interaentricular
branch which runs downwards in the groove of the
same name. The further continuation of the left
coronary artery is called the circumflex artery
(Figs1B.22a and b and18.23).

2 After giving off the anterior interventricular branch
the artery runs to the left in the left anterior coronary
sulcus.

3 It winds round the left border of the heart and
continues in the left posterior coronary sulcus. Near
the posterior interventricular groove it terminates by
anastomosing with the right coronary artery.

Branches

I Large branches
a. Anterior interventricular.
b: Branches to the diaphragmatic surface of the left
ventricle, including a large diagonal branch.

A=Anterior P= Posterior S =Septal

Fig. 18.23: Origin of the coronary arteriesfrom the aorticsinuses

and their course in the coronary sulcus, as seen after removal

of the atria (anatomical position)

(^2) Small branches
a. Left atrial
b. Pulmonary
c. Terminal
Areoof Eis utian
1 Left atrium
2 Ventricles
a. Greater part of the left ventricle, except the area
adj oining the posterior interventricular groove.
b. A small part of the right ventricle adjoining the
anterior interventricular groove.
Pulmonary
Anterior
interventricu la r
branch of the left
coronary artery
Left
posterior
aortic
SINUS
Left
Anterior
Anterior aortic sinus
Right coronary
artery
Marginal
branch
Right
Ascending aorta
Left coronary artery
Circumflex branch
Anterior
interventricular
branch
Circumflex
branch
of left
coronary
artery
Right
coronary
artery
Marginal branch
Posterior interventricular branch
(a)
Figs 18.22a and b: Arterial supply of heart: (a) Sternocostal surface, and (b) diaphragmatic surface