Measurements done related to caecum and appendix in each group are shown in Table 1.

When all parameters were compared in the 3rd group between genders there was no significant correlation seen as p values were 0.509, 0.981, 0.09, and 0.846. for distance from the liver, length of appendix, diameter of appendix, and length of mesoappendix.

When all parameters were compared in the 2nd group between genders there was no significant correlation seen in the distance from the liver, the diameter of appendix, and length of mesoappendix as the p values were 0.601, 0.34, and 0.863. While significant correlation was seen in the length of appendix as the p value was 0.04.

When all parameters were compared in the 1st group between genders there was no significant correlation seen as p-values were 0.441, 0.101, 0.579, and 0.501 for distance from the liver, length of the appendix, the diameter of appendix, and length of mesoappendix.

When comparing parameters between the groups by Anova test there was a significant correlation seen as p-value was 0.001, 0.000, 0.000, 0.037 for distance from the liver, length of the appendix, the diameter of appendix, and length of mesoappendix.

When comparing parameters within the groups by Post hoc Tukey’s test there was a significant correlation seen for distance from the liver within groups 1 and 3 as p-value was 0.000. The length of the appendix was significantly correlated within all the groups as p-value was < 0.05. The diameter of appendix was significantly correlated within groups 1 and 2 as the p-value was 0.001 and groups 1 and 3 it was 0.000. The length of the mesoappendix was significantly correlated within groups 1 and 3 as p value was 0.028 (Table 2).

In the female’s caecum and appendix were in the right lumbar, right iliac fossa, and subhepatic in 50%, 30%, and 20% of cases. In male’s caecum and appendix were in the right lumbar and right iliac fossa in 40% and 60% of cases.

In the females and males’, the position of appendix was retrocaecal (12o, clock), paracolic (11 o’clock), inguinal (6 o’clock), splenic (2 o’clock), and pelvic (4 o’clock) in 20% each, 30% each, 30% and 10%, 10% and 30%, 10% in each of cases. There was no promonteric position observed.

In females, all caecum (100%) belongs to type 4 while in males 40% belongs to type 3 and 60% belongs to type 4.

In the female’s caecum and appendix were in the right lumbar, right iliac fossa, and subhepatic in 40%, 10%, and 50% of cases. In male’s the caecum and appendix were in the right lumbar and subhepatic in 70% and 30% of cases.

In the females and males’, the position of the appendix was retrocaecal (12o, clock), paracolic (11 o’clock), inguinal (6 o’clock), promonteric (3 o’clock), and pelvic (4 o’clock) in 30% each, 20% each, 10% and 20%, 20% and 10% and 20% in each of cases. There was no pelvic position observed.

In females 10% of the caecum belongs to type 2, 70% belongs to type 3 and 20% belongs to type 4 while in males 20% of the caecum belongs to type 2, 70% belongs to type 3, and 10% belongs to type 4.

In the female’s caecum and appendix were in 50% of cases each in the right lumbar and subhepatic region. In male’s caecum and appendix were in the right lumbar and subhepatic in 33.33% and 66.67% of cases.

In the female’s position of the appendix was retrocaecal (12o, clock), inguinal (6 o’clock), splenic (2 o’clock), and pelvic (4 o’clock) in 25% of cases each. There was no paracolic and promonteric position observed in females. In the male position of the appendix was retrocaecal (12 o, clock), paracolic (11o’clock) and inguinal (6 o’clock) in 16.67%, 50%, and 33.33% of cases. There was no splenic, promonteric, and pelvic position observed in males.

In females 50% of caecum each belongs to type 1 and 2 while in males all caecum (100%) belongs to type 1.

The thickness of all histological layers of the appendix in all trimesters of the fetus is shown in Table 3.

The epithelium was simple columnar with well-developed goblet cells. Crypts and intestinal glands were also developed in the lamina propria during the 1st trimester. Lymphatic follicles were scattered and diffused in the lamina propria during the 2nd trimester. Muscularis mucosa was well-developed in the 2nd trimester (Fig. 5).

H&E-stained microscopic images of appendix during 2nd trimester at 10x magnification with appearance of muscularis mucosa

Appendix mucosa appeared to be thinner in the first trimester. During the second trimester, the width of the mucosa increased. In the third trimester, the mucosa appears to be thinner than in the second trimester but thicker than in the first trimester. The width of mucosa increased both due to the development of epithelium and the increase in the width of lamina propria.

While correlating mucosa development during the three trimesters it was noted that a significant correlation was noted between1st and 2nd trimesters as (P value=0.047) and between 1st and 3rd trimesters as (P value=0.010) while between 2nd and 3rd trimesters it was not significant (Table 4).

The width of the submucosa in the appendix goes on increasing as the increase in trimesters. Submucosal plexus was seen during the first trimester. During 2nd and 3rd trimester the area occupied by the plexus increases due to increase in the cell proliferation. In submucosa, lymphatic follicles were seen after disrupting the muscularis mucosa. Connective tissue and blood vessels in the submucosa were also appreciated.

While correlating submucosa development during the three trimesters it was noted that a significant correlation was noted between 1st and 3rd trimesters as (P value = 0.048) while between 1st and 2nd trimesters and between 2nd and 3rd trimesters it was not significant (Table 4).

The width of the muscularis externa in the appendix goes on increasing as the increase in trimesters. Both circular and longitudinal muscles were seen to be well-developed in the 1st trimester (Fig. 4). Myenteric plexus was seen during the first trimester. During the 2nd and 3rd trimester the area occupied by the plexus increases due to increase in the cell proliferation.

While correlating muscularis externa development during the three trimesters it was noted that a significant correlation was observed between 1st and 2nd trimesters as (P value=0.004) and between 1st and 3rd trimesters as (P value=0.049) while between 2nd and 3rd trimesters it was not significant (Table 4).

Lymphatic follicles were scattered and diffused in the lamina propria during the 2nd trimester. During the 3rd trimester, they got organized and lymphatic nodules with germinal centers were well-developed. The area occupied by them was 50,349mm2 during the 2nd trimester and later it became 35,266mm2. This may be due to the good organization of the lymphatic follicles with the germinal centers (Fig. 4).

The histological comparison of all the trimesters in the picture is shown in Fig. 6.

H&E-stained microscopic images of appendix at 10x magnification. A 1st trimester, B 2nd trimester, C 3rd trimester