Conotruncal anamolies

Conotruncus Embryology & Anomalies

Msn Pavan Kumar
Nizam’s Institute of Medical Sciences
,Panjagutta,Hyderabad,India.
msnpavan@gmail.com

 The conotruncus comprises collectively two myocardial subsegments,
the conus and the truncus.
 Conus is the myocardial segment between ventricle and semi lunar
valves which gives rise to sub arterial coni.
 Truncus is the fibrous segment between semi lunar valves and aortic sac
which gives rise to great arteries.

 Embryology
1. Septation of conus and truncus.
2. Rotation and absorption.
3. Development of semi lunar valves.
4. Important structures involved
a) Neural crest cells.
b) Secondary heart field.
 Congenital heart diseases d/t conotruncus
 Genetic defects in Conotruncal

Embryology - Septation of conus and truncus.
 4 truncus and 2 conal cushions develop.
 Dextro- sinistro cushions of both conus and truncus fuse to form
Conotruncal septum.
 Intercalated cushions play an role in formation of semi lunar valves

Embryology - Septation of conus and truncus.

 Because the cushions are
dextro-superior and sinistro
inferior in truncus and
dextro-dorsal and sinistro-
ventral in conus union
forms a spiral septum than
true lineal relation.

For convenience it is represented as linear structure

Embryology - Rotation and absorption.
 Aorta will be in connection with RV and PA with LV.
 There are two rotations one at conoventricular junction and other
at Conotruncal junction.
 Both rotations are counterclockwise around 110º

 Conoventricular rotation brings aorta in continuation with LV and
PA with RV.
 Conotruncal rotation brings the normal position of aorta in relation
to PA ( left and posterior to PA)

 Second most important thing is absorption of conus.
 Out of the two coni which ever remains persistent and grows
pushes the artery more anterior and superior direction bringing it
in direct connection with RV.
 In normal heart sub aortic conus is absorbed completely.

Embryology – Semilunar valves.

Septation at valvular level occurs in intercalated cushions
leading to formation partial aortic and pulmonary valve.
The remaining part is formed by Conotruncal cushions.

Embryology – Important Structures For Development Of Conotruncus.
 Second heart field cells and neural crest cell play important role in
development of conotruncus


 Conotruncal defects
1. Truncus
2. TOF (with absent PV& PA)
3. DORV
4. DOLV
5. D-TGA
6. Conoventricular septal defects
7. Interrupted aortic arch type B

Truncus arteriosus.
Failure of aortopulmonary septum to Septation give rise to
persistent truncus arteriosus.

Truncus

Conus

TOF:
Infundibular septum which arises from conal septum moves
anteriorly and superiorly causing components of TOF

DORV
Conoventricular
rotation is based on
which coni persists.
Artery with coni will
be anterior and
superior and
connected to RV
If both coni are
present both arise
from RV - DORV

DORV

In DORV, rotation of great arteries driven by conal development that changes not
the position of VSD.

Type More prominent Less prominent VSD commited
coni coni to
TOF(40%) Subpulmonic Sub aortic Aorta
VSD (15%) Subpulmonic Sub aortic Aorta
TGA(20%) Subaortic Sub pulmonic PA
Variants ---- Both Both
(DC<10%)
Variants Both ---- Non committed
(NC<10%)

DOLV
In DOLV both coni
are absent hence
both arteries are
posterior and arising
from LV

D - TGA

Cono ventricular septal defects.
 Absence of conal(Infundibular) septum leads to formation of
malaligned , subinfundibular , subpulmonic VSD .

Conotruncal anamolies

More Related Content

What's hot (20)

Viewers also liked (20)

Similar to Conotruncal anamolies (20)

More from https://aiimsbhubaneswar.nic.in/ (20)

Recently uploaded (20)

Conotruncal anamolies