*4.1.2.3 Sciatic notch index*

The sciatic notch index is given by dividing the hundred times width of sciatic notch with its depth.

ð Þ Width of the sacrum*=*diameter of sacrum ∗ 100 (5)

acetabular height (vertical diameter) and indices 1 (total pelvic height/acetabular height), 2 (midpubic width/acetabular height) and 3 (pubic length/acetabular height). Pelvic brim depth, minimum width of ischiopubic ramus and indices 4 (pelvic brim chord \* pelvic brim depth) and 5 (pubic length \* 100/ischial length) were also good discriminators of sex. The remaining parameters used in the study were not significant as they showed a lot of overlap between the male and female categories. The results indicated that one exclusive criterion for sexing was index 3

The sacrum is a large flattened triangular bone formed by the fusion of five sacral vertebrae and forming the posterosuperior part of bony pelvis. It articulates on either side with the corresponding innominate or hip bone forming sacroiliac joint. Morphological and metric differences of sex determination are given in the

The sacral index [30] is given by dividing the hundred times length of anterior superior breadth of the sacrum at the first sacral vertebrae with anterior length of sacrum. The anterior length was measured along the midline from the anterosuperior margin of the promontory to the middle of antero-inferior margin of the last sacral vertebra. The anterior superior breadth was measured between the

¼ ð100 ∗ Anterior superior breadth of sacrum*=*Anterior length of the sacrumÞ

The study [30] also calculated the demarcating point (DP) which increases the accuracy by 100%. The range of sacral index in male is 80.7–106.4 and in females is 93.1–108.8 and DP for sacral index in males is less than 90.29 and in females is

In a study [31] done on 150 fully ossified dry human sacrums (59 male and 91 females), it was observed that the mean straight length of sacrum in the male and in the female was 104.27�5.76 mm and 92.82�7.59 mm respectively. The mean width of sacrum in the male and the female was 99.51�5.80 mm and 102.98�6.69 mm respectively. The mean sacral indices were 95.42�3.14 and 111.27�7.66 in males and

2 Curvature More evenly distributed Curvature not seen in the upper

**Sr. No Trait Male Females** 1 Size and shape Longer, Narrower Shorter, wider

3 Sacral Promontry Well marked Less marked 4 Body of first sacral vertbra Larger Smaller

vertebrae

5 Sacroiliac articulation Large, Extends to 2.5to 3

*Showing difference in human sacrum with respect to sex.*

(7)

half, lower half curves suddenly

Small, Extends to 2 to 2.5 vertebrae

(pubic length/acetabular height).

*Forensic Osteology and Identification*

*DOI: http://dx.doi.org/10.5772/intechopen.99358*

lateralmost points of the ala of the sacrum.

**4.2 Sacrum**

**Table 7**.

*4.2.1 Sacral index*

Sacral Index

greater than 112.43.

females respectively.

**Table 7.**

**115**

In adult males: 145; in adult females: 166. In the male fetus: 4–5; in the female fetus: 5–6.

### *4.1.2.4 Chilotic line index*

The chilotic line index is obtained by dividing the hundred times length of the sacral part of the pectineal line with the pubic part of pectineal line.

ð Þ Sacral part of pectineal line*=*pubic part of pectineal line ∗ 100 (6)

In males: the CLI is greater than 100, In females: the CLI is less than 100.

These indexes are not used routinely. Nowadays, discriminant function analysis is used by anthropologists. This was first used by Howells [28]. He worked on Gaillard's skeletal collection (75 males, 69 females) and took four parameters, ischial and pubic lengths and the index obtained from it, he took four measurements of the greater sciatic notch and acetabular region. These included sciatic height, cotylosciatic length (shortest distance from acetabular rim to greater sciatic notch), cotylopubic length (from acetabular rim to pubic symphysis) and the difference between SS-SA, in which SS is the distance between the anterior superior iliac spine and the closest point on the greater sciatic notch, and SA is the distance between the anterior superior iliac spine and the closest point on the auricular surface (**Table 6**).

In another study, Dixit [29] observed twelve measurements and five indices from 100 human hip bones of unknown sex of Indian origin. Each of the hip bones was classified as male, female and intermediate on the basis of morphological characters. Afterwards discriminant function analysis was done and it was observed that sex can be accessed with greater accuracy from parameters such as the


#### **Table 6.**

*Showing discriminant function coefficients for determining sex from the Os Coxa.*

#### *Forensic Osteology and Identification DOI: http://dx.doi.org/10.5772/intechopen.99358*

acetabular height (vertical diameter) and indices 1 (total pelvic height/acetabular height), 2 (midpubic width/acetabular height) and 3 (pubic length/acetabular height). Pelvic brim depth, minimum width of ischiopubic ramus and indices 4 (pelvic brim chord \* pelvic brim depth) and 5 (pubic length \* 100/ischial length) were also good discriminators of sex. The remaining parameters used in the study were not significant as they showed a lot of overlap between the male and female categories. The results indicated that one exclusive criterion for sexing was index 3 (pubic length/acetabular height).
