This document discusses the coronary artery anatomy as seen on CT scans. It begins with an overview of the normal radiological anatomy of the coronary arteries, including their origins and branches. It then discusses the left main coronary artery in more detail, describing how it bifurcates into the left anterior descending artery and circumflex artery. Specific branches such as the diagonal and marginal branches are also described. The right coronary artery anatomy is then reviewed, along with the segments and branches. Coronary dominance is discussed. Examples of normal coronary arteries as seen on various CT views are also provided.

1. Dr/AHMED ESAWY

2. An Article By
Dr. Ahmed Esawy
MBBS M.Sc. MD
Dr/AHMED ESAWY

3. Dr/AHMED ESAWY

4. 5 PARTS
• 1-CT radiological anatomy
• 2-pathology
• 3-technique
• 4-indication
• 5-Manifestation of coronary artery diseases in
MSCTCA/MRCA
Dr/AHMED ESAWY

5. coronary
radiological
Anatomy
Dr/AHMED ESAWY

6. Coronary arteries
The epicardial coronary artery
system consists of the left and right
coronary arteries.
Dr/AHMED ESAWY

7. Normal Anatomy
R and L coronary arteries arise from the R and L
aortic sinuses (of Valsalva)
Usually within 1cm superior to aortic valve
Arteries originate orthogonal to aortic wall
Epicardial (extramural course) course
Dr/AHMED ESAWY

8. The aortic valve has three leaflets, each
having a cusp or cup-like configuration.
These are known as the left coronary cusp
(L), the right coronary cusp (R) and the
posterior non-coronary cusp (N).
Just above the aortic valves there are
anatomic diltations of the ascending
aorta, also known as the sinus of Valsalva.
The left aortic sinus gives rise to the left
coronary artery.
The right aortic sinus which lies anteriorly,
gives rise to the right coronary artery.
The non-coronary sinus is postioned on
the right side.
Origin of coronary artery
Dr/AHMED ESAWY

9. Coronary artery
• The coronary artery arises just
superior to the aortic valve and
supply the heart
• The aortic valve has three cusps –
#left coronary (LC),
#right coronary (RC)
#posterior non-coronary (NC)
cusps.
Dr/AHMED ESAWY

10. Left coronary (LC), right coronary (RC) and posterior non-coronary (NC) cusp
The left coronary artery (LCA) is also known as the left main.
The LCA arises from the left coronary cusp.
Dr/AHMED ESAWY

11. RCA
LCA
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12. Dr/AHMED ESAWY

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14. On the left an overview of the coronary arteries in the anterior
projection.
Left Main or left coronary artery (LCA)
Left anterior descending (LAD)
diagonal branches (D1, D2)
septal branches
Circumflex (Cx)
Marginal branches (M1,M2)
Right coronary artery
Acute marginal branch (AM)
AV node branch
Posterior descending artery (PDA)
RCA, LAD and Cx in the anterior projection
.Dr/AHMED ESAWY

15. On the left an overview of the coronary arteries in the
right anterior oblique projection.
Left Main or left coronary artery (LCA)
Left anterior descending (LAD)
diagonal branches (D1, D2)
septal branches
Circumflex (Cx)
Marginal branches (M1,M2)
Right coronary artery
Acute marginal branch (AM)
AV node branch
Posterior descending artery (PDA)
RCA, LAD and Cx in the right anterior oblique projection
.Dr/AHMED ESAWY

16. On the left an overview of the coronary arteries in the
lateral projection.
Left Main or left coronary artery (LCA)
Left anterior descending (LAD)
diagonal branches (D1, D2)
septal branches
Circumflex (Cx)
Marginal branches (M1,M2)
Right coronary artery
Acute marginal branch (AM)
AV node branch
Posterior descending artery (PDA)
RCA, LAD and Cx in the lateral projection
.Dr/AHMED ESAWY

17. SEGMENTAL CORONARY ARTERY ANATOMY
16 SEGMENTS
MODIFIED 17 SEGMENTS
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18. Right coronary artery (1-4 segments)
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19. Left main coronary artery (5 segment)
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20. Left anterior descending coronary
artery (6-10 segments)
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21. Left circumflex coronary artery
(11-15 segments)
Dr/AHMED ESAWY

22. ramus intermedius
The ramus intermedius is a variant coronary artery resulting from
trifurcation of the left main coronary artery . It is present in 20%
(range 15-30%) of the population.
It can have a course similar to the obtuse marginal branches of the
left circumflex artery or the diagonal branches of the left anterior
descending and thus can supply either the anterior or medial
aspect of the heart .
SEGMENT NAMEVESSEL NAMESEGMENT NO
Ramus intermediusRamus intermedius17
Dr/AHMED ESAWY

23. Modified 17-segment of the AHA
reporting system
Dr/AHMED ESAWY

24. Modified 17 segments AHA
Right Coronary Artery
SEGMENT NAMEVESSEL NAMESEGMENT NO
Proximal RCARight coronary artery1
Mid RCA2
Distal RCA3
Posterior descending artery4
Right posterolateral16
left posterolateral15
Dr/AHMED ESAWY

25. Modified 17 segments AHA
Left Circumflex artery
SEGMENT NAMEVESSEL NAMESEGMENT NO
Proximal LCALeft circumflex artery11
Distal LCA13
First obtusomarginal OM12
second obtusomarginal OM14
Dr/AHMED ESAWY

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30. Normal coronary arteries as seen on curved multiplanar reformations
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31. Left coronary artery
• Arises from left coronary
cusps
• Travels between RVOT
anteriorly and left atrium
posteriorly.
• Almost immediately
bifurcate into left anterior
descending and left
circumflex artery.
• Length – 10-15mm .
Dr/AHMED ESAWY

32. LCA divides into LAD and Cx
Dr/AHMED ESAWY

33. Left coronary
artery
LAD
Diagonal artery
Lt Conus artery
Anterior Septal
br
Circumflex
artery
Obtuse marginal
branches
Ventricular
branches
Atrial rami
Dr/AHMED ESAWY

34. LEFT CORONARY ARTERYDr/AHMED ESAWY

35. LT CORONARY ARTERY
1) Left atrium.
2) Ventricles
i) Greater part of the left ventricle, except the area
adjoining the posterior IV groove.
ii) A small part of the right ventricle adjoining the anterior
IV groove.
3) Anterior part of the IV septum.
4) A part of the left br. Of the AV bundle.
Dr/AHMED ESAWY

36. DOMINANCE
• Determined by the arrangement that which artery
reaches the crux & supply posterior descending
artery
• The right coronary artery is dominant in 85% cases.
• 8% cases - - circumflex br of the left coronary artery
• 7% both rt & lt coronary artery supply posterior
IVseptum & inferior surface of the left ventricle-here
it is balanced dominance.
Dr/AHMED ESAWY

37. Coronary dominance is based on the vessel that
gives rise to the posterior descending artery
which supplies the Atrio-ventricular node.
Recognized by the presence of septal perforating
branches, arises from the RCA in 80% from and
the LCx in 10% of the population.
Co-Dominance is found in 10% of the population
where the posterior interventricular artery is
formed by both the RCA and LCx.
Dominance
Dr/AHMED ESAWY

38. Dominant RCA
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39. In 15% of cases a third branch arises in between the LAD and the Cx, known as the ramus
intermedius or intermediate branch.
This intermediate branche behaves as a diagonal branch of the Cx.
Dr/AHMED ESAWY

40. The Left coronary artery
• Oblique volume-
rendered image of
the top of the heart
shows the origins of
the left main
coronary artery.
Dr/AHMED ESAWY

41. The LAD travels in the anterior interventricular groove
and continues up to the apex of the heart.
The LAD supplies the anterior part of the septum with
septal branches and the anterior wall of the left
ventricle with diagonal branches.
The LAD supplies most of the left ventricle and also
the AV-bundle.
LAD
Dr/AHMED ESAWY

42. The Left Anterior Descending artery
• Oblique volume-
rendered image
shows the LAD
artery
Dr/AHMED ESAWY

43. CT image of the LAD in RAO projection
Dr/AHMED ESAWY

44. The diagonal branches come off the LAD and run laterally to supply the antero-lateral
wall of the left ventricle.
The first diagonal branch serves as the boundary between the proximal and mid
portion of the LAD.
There can be one or more diagonal branches: D1, D2 , etc.
Dr/AHMED ESAWY

45. The proximal left anterior
descending coronary artery
segment (6) is the anterior branch
of the left main coronary artery (5,
Panels A–D). Segment 6 of the left
anterior descending coronary
artery then bifurcates into the
mid-left anterior descending (7)
and the first diagonal branch (9,
Panels A–D). Further
In Panels E and F, the conus
branch (arrows, first side branch
of the RCA), which travels cranial
to the proximal RCA segment, is
also visible.
Dr/AHMED ESAWY

46. caudally, the mid-left anterior descending coronary artery gives off the distal segment (8)
and the second diagonal (10, Panels E–J)
Dr/AHMED ESAWY

47. The Cx lies in the left AV groove between the left atrium and left ventricle and
supplies the vessels of the lateral wall of the left ventricle.
These vessels are known as obtuse marginals (M1, M2...), because they supply the
lateral margin of the left ventricle and branch off with an obtuse angle.
In most cases the Cx ends as an obtuse marginal branch, but 10% of patients have
a left dominant circulation in which the Cx also supplies the posterior descending
artery (PDA).
Marginal branches arise from the Cx and supply the lateral Margin of the left
ventricle.
Circumflex (Cx)
Dr/AHMED ESAWY

48. The Left Circumflex artery
• An axial oblique
volume-rendered
image shows the LCX
artery
Dr/AHMED ESAWY

49. Circumflex and LAD seen in Lateral projection
.
Dr/AHMED ESAWY

50. The proximal LCX segment
(11) is the posterior branch of
the left main coronary artery
(5, Panels A–D). Further
down, the proximal left
circumflex splits into the
mid-left circumflex (13) and
the first (obtuse) marginal
branch (12, Panels E–H). The
mid-left circumflex (13) then
gives off the distal left
circumflex (15, Panels F–H)
Dr/AHMED ESAWY

51. obtuse) marginal branches (14, Panels E–J), which supply the inferolateral
myocardial segments
Dr/AHMED ESAWY

52. (In the case of left coronary artery dominance, the distal
circumflex (15) ends as the posterior descending artery (4a),
whereas in right coronary dominance, as in this case,the RCA gives
rise to the posterior descending and at least one posterolateral
branch. The sinus node artery (arrow in Panels A and B) is the
first branch of the LCX in this patient.; Asterisk papillary muscles;
Dr/AHMED ESAWY

53. Right coronary artery
• Originates from right
coronary sinus of
Valsalva
• Courses through the
right AV groove
between the right
atrium and right
ventricle to the inferior
part of the septum
.
Dr/AHMED ESAWY

54. Right Coronary Artery (RCA)
In 50-60% the first branch of the RCA is the small conus branch, that supplies the
right ventricle outflow tract.
The next branches are some diagonals that run anteriorly to supply the anterior wall
of the right ventricle.
The large acute marginal branch (AM) comes off with anacute angle and runs along
the margin of the right ventricle above the diaphragm.
The PDA supplies the inferior wall of the left ventricle and inferior part of the
septum.
Dr/AHMED ESAWY

55. Branches of RCA
Right coronary artery
Conus artery
Sinu nodal artery
Marginal artery
Post. Descending IV artery
AV nodal artery-
Conus branch
SINU NODAL BRANCH
AV Nodal Branch
Dr/AHMED ESAWY

56. RCA, LAD and LCx in Anterior projection
.
Dr/AHMED ESAWY

57. The Right coronary artery
• oblique volume-
rendered image
shows the RCA .
Dr/AHMED ESAWY

58. • Conus branch – 1st branch supplies the RVOT
• Sinus node artery – 2nd branch - SA node.(in 40%
they originate from LCA)
• Acute marginal arteries-Arise at acute angle and runs
along the margin of the right ventricle above the
diaphragm.
• Branch to AV node
• Posterior descending artery : Supply lower part of the
ventricular septum & adjacent ventricular walls.
Arises from RCA in 85% of case.
Dr/AHMED ESAWY

59. Right coronary anatomy
AO
LA
RCA
CONUS BR
RCA
SAN
1 2
3 4
RCA
AM
Dr/AHMED ESAWY

60. RCA
AM
AM
Dr/AHMED ESAWY

61. Area of distribution
RT CORONARY ARTERY----
1)Right atrium
2)Ventricles
i) greater part of rt. Ventricle except the area adjoining the
anterior IV groove.
ii) a small part of the lt ventricle adjoining posterior IV
groove.
3)Posterior part of the IV septum
4)Whole of the conducting system of the heart, except part
of the left br of AV bundle
Dr/AHMED ESAWY

62. LEFT: RCA comes off the right sinus of ValsalvaRIGHT:
Conus artery comes off directly from the aorta
Dr/AHMED ESAWY

63. The large acute marginal branch (AM) supplies the lateral wall of the right ventricle.
In this case there is a right dominant circulation, because the posterior descending
artery (PDA) comes off the RCA
Dr/AHMED ESAWY

64. a
The RCA
with all its
segments in
axial slices
thickness in the axial orientation for comparison (right panels). The proximal segment of the RCA (1) comes off the aorta, arising from the
right sinus of Valsalva (Panels A and B). It first moves anteriorly and then (as segment 2) caudally in the right atrioventricular sulcus
(Panels C and D) to the posterior surface of the heart (Panels E and F), where it again moves
in the horizontal plane on the diaphragmaticDr/AHMED ESAWY

65. The RCA with all its segments in axial slices
face of the heart as segment 3. At the crux cordis, segment 3 bifurcates into the posterior
descending artery (4a) and the right posterolateral branch (4b in Panels G and H).
Dr/AHMED ESAWY

66. In cases of dominance of the RCA (as in this case), segments 4a and b are side
branches of the RCA. In case of left coronary artery dominance, the posterior
descending artery (4a) is part of the LCX
Dr/AHMED ESAWY

67. Three dimensional reconstruction of the heart (A). Curved multiplanar
reconstructions of the RCA (B), LAD (C) and LCx arteries (D) revealed the
absence of atherosclerotic abnormalities (LAD: left
Dr/AHMED ESAWY

68. A- the RCA is a dominant patent artery of normal caliber. B- The circumflex artery is
patent of normal caliber.
Dr/AHMED ESAWY