الفهرس 
Anatomy of thoracic aortaOnly 14 pages are availabe for public view
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Abstract
•Assessment of the quantitative values of the normal thoracic aorta in different age and sex groups is ultimately necessary . This to throw a light on the normal growth and development of the thoracic aorta in young ages and to detect the normal anatomical age-related changes that are encountered upon aging.
The aim of this work was to detect the average diameters of normal thoracic aorta in normal asymptomatic subjects .
•Computed tomography of the thoracic aorta carried out on the chest of 180 normal healthy individuals including 90 females and 90 males , which were selected from healthy volunteers.
•-Measurements:
A - The ascending aortic anteroposterior and lateral diameters (ATD) and descending aortic anteroposterior and lateral diameters (DTD) and the averaged diameter of them , were performed, at three levels
Level A : placed 3 cm caudal to the top of the aortic arch.
•Level B: At the level of pulmonary artery bifurcation.
•Level C : At the level of the dome of the right hemi diaphragm.
B- Proximal aortic arch diameter and distal aortic arch diameter, PAAD and DAAD respectively, perpendicular to the long axis of the aortic arch 1.5 cm caudal to the top of the aortic arch
C-The thoracic vertebral body width(VW) .
D- First aortic index (AI 1) VW/ATD at level (B).
E-Diameter of chest cavity (CAPD) at the levels (C) of the aortic measurements.
F-Second aortic index(AI 2) CAPD /ATD at level (B).
G-Pulmonary artery (trunk) widest diameter (PAD1) at the level of pulmonary trunk bifurcation .
H-Pulmonary artery (trunk) diameters(PAD2) 1cm proximal (below) pulmonary trunk bifurcation.
I-Pulmonary ratio (Pr) PAD2 /ATD at level (B): were calculated using the ratio between average of PAD2 and ATD at level (B).
J-Aortic root diameter (ARD)at the sinuses of valsalva. .
K-Aortic ratios (Ar) : They are relative aortic diameters normalized to diaphragmatic level (level C) :
- First aortic ratio (Ar1)=average ATD at level A / average DTD at level (C).
- Second aortic ratio (Ar2)=average ATD at level B / average DTD at level (C).
- Third aortic ratio (Ar3) = average DTD at level A / average DTD at level (C).
- Fourth aortic ratio (Ar4)= average DTD at level B / average DTD at level (C).
•The mean values of the ascending thoracic aortic diameters (ATD) , in the male groups at level (A) and (B) increased steadily with age and showed a significant increase between the first and second groups and also between the fifth and sixth groups, and insignificant increase from the second to the fifth age groups.
•The descending thoracic aortic diameters (DTD) in the male groups, were increased steadily by age. It showed a statistical significant increase between the first four consecutive age groups and a highly significant difference between the fifth and sixth male groups. It showed insignificant increase between the fourth to the fifth groups.
The parameters of PAD1, and PAD2 increased steadily by age with a significant difference only in the first 3 groups but in the last three groups PAD1 and PAD 2 parameters did not change with increasing age, reaching maximum of (30. 7+1.31mm) .The parameters of PAD1, and PAD2 of males were mostly more than that of females in all age groups, while the lateral diameters of PAD2 were smaller than the anteroposterior diameters, which is due the lateral compression of the PAD2 at this level.
•The pulmonary ratio (PAD2/AT DB ) decreases with age and shows no difference between male and female groups, which is almost fixed between (0.85+0.11 to 1.2+0.21).
•The thoracic vertebral width (VW): In both sexes it was increased between the first three groups then it showed no changes between the last three groups.
•The first aortic index (AI 1) VW/ATD(B): In both sexes the mean values showed constant values.
•The parameters of the chest anteroposterior diameter: In groups one, two and five , the mean values of (CAPD) were higher in males than in females , with an insignificant difference, however the mean values of (CAPD) were higher in males than in females with a statistical significant difference in the third , fourth and six age groups
•The second aortic index (AI2) showed no changes with age advance and also showed an insignificant difference between males and females in all the tested groups with almost fixed mean values in all the twelve age groups .
•The measured parameters of the aortic root diameter in male groups: The mean values of aortic root diameter (ARD) increased steadily by age advance, but showed a significant difference between the (first and second), (second and third), (third and fourth) and the (fifth and sixth) age groups (P<0.05), while the fourth and fifth age groups showed no significant difference between them .This was referred to that the mean age of these two groups were very near to each other.
•The aortic ratios: The mean values of the aortic ratios in both sexes showed constant values in all the age groups. These ratios are very important ratios to determine if any part of the aorta is within normal limits or not. The diaphragmatic level of the thoracic aorta was used as a reference level, because aneurysms and hypoplasia are rarely affect this level.
•As regard the measured parameters of the ascending thoracic aorta in female age groups: The mean values in female groups of ascending thoracic aorta (ATD) at both (A) and (B) levels, were increased steadily by age advance but showed insignificant increase between the (first and second) and between (the fifth and sixth) female age groups. However while the difference between the (second and third), (third and fourth) and (founth and fifth) female groups, showed a statistically significant difference.
•The mean values of the proximal aortic arch diameters (PAAD) and distal aortic arch diameters (DAAD) increased steadily with age, and showed a significant increase between the first and second groups and also between the second and third groups while showed insignificant increase from the third to the sixth age groups.
•The mean values of descending thoracic aorta (DTD) in female groups at (A), (B) and (C) levels, were increased steadily by age advance but it showed insignificant increase between the (first and second) and between the (fifth and sixth ) ,while the other age groups showed statistically significant difference between the data of descending thoracic aorta.
•Regarding the sex difference in thoracic aorta: The mean values of the average diameter of (ATD) and (DTD) at the three levels of the work (A), (B) and (C), the data obtained from the males groups were higher than that obtained from the female groups but with insignificant difference in the most of the mentioned parameters.
•The mean values of the thoracic vertebral body width (VW) and the chest anteroposterior diameter (CAPD), were higher in males than their corresponding mean values in females and showed a significant difference between the most of the female and male groups regarding the mentioned parameters.
•Also, the mean values of the aortic root diameter (ARD) were higher in males than in females and showed statistical significant difference more between the adult groups than that of the pediatric childhood groups.