Cephalometry is a branch of anthropometry that deals with the study of human head measurements [1] . It comprises of two indices; the cephalic (cranial) and the proscopic (facial) indices. These indices are important parameters, useful in anthropological studies for ascertaining variations [2] .

The facial and ear indices are some of the most important cephalometric parameters useful in inter-racial classification and intra-racial categorization. Facial proportions change with age and according to sex in any given race owing to variations in skeletal dimensions and muscle development. They are also dependent on factors such as diet, health, and climatic influences, which are known to be important determinants of growth and development [3] . The face is the anterior aspect of the head from the forehead to the chin and from one ear to the other [4] . Facial measurements are useful in forensic medicine, plastic surgery, orthodontics, clinical diagnosis and treatment planning [5] . Table 1 shows five categories of face based on the facial index namely: hypereuryproscopic, euryproscopic, mesoproscopic, leptoproscopic, and hyperleptoproscopic [6] .

The ear is a defining characteristic of the face useful in identification hence its subtle structures convey signs of age and gender that are unmistakable, though difficultly defined [7] . The shape of the ear can be referred to as type I (tapering-acute angle, where the lobe is free from the check), type II (square-right angle) and type III (pendulous-obtuse angle) according to the appearance of the lobule [8] . Various parameters have been used to establish individual identification and anthropometry of external features of the auricle is one of them [7] .

Efik is an ethnic group located primarily in southeastern and South-South geopolitical zone, the southern part of Cross River State in Nigeria. The Efik people also occupy southwestern Cameroon in a place called Bakassi. Efiks speak the Efik language which is a Benue-Congo language of Cross River family. The Ibibio people are from South-South geopolitical zone in Akwa Ibom State, Nigeria [9] .

It has been noted that human head, ear, and face shapes from different ethnic groups vary remarkedly. The cause of these variations has been attributed to several environmental factors [10] . Measurements of these indices therefore become a necessity to prove any possible linkage in origin which a particular ethnic group have with another especially closely associated ethnic groups. Although studies of this type may have been carried out in children of other ethnic groups [11] , no such study to the best of our knowledge has been carried out on children of Efik and Ibibio ethnic groups in Nigeria. Hence this study was carried out to help distinguish the ear and facial configurations between female children of Efik and Ibibio ethnic groups.

This study comprised of 300 Efiks and 300 Ibibios (600 subjects) ranging in age from 2 to 10years. The subjects were randomly selected from the following schools; St. Bernard’s International Nursery/Primary School; Brotherhood Primary School; Angelic International Schools; De Wisdom International Schools; Aknes Memorial Schools; and PCN Primary School in Calabar South and Municipality Local Government Areas of Cross River State. And also from Q.I.C Group School, Ikot Oku; St. Michael A.C Primary School, Four Towns; Nuco Nursery/Primary School, Uyo Oku; Government Primary School, Ikot Ntuen Oku; Government Primary School, Ibiaku Itam II; and Government Primary School, Afaha Ube Itam in Uyo and Itu Local Government Areas of Akwa Ibom State. The parents and grandparents of subjects from Cross River State were Efiks, while those from Akwa Ibom State were Ibibios. In addition, the subjects were residents of the area. All subjects had a normal facial and auricular configuration, with no congenital facial anomaly, ear malformation, facial trauma, or facial disorder.

The materials that were used for this research work are: Spreading caliper, Biro pen, Notebook.

The ethical approval for this study was obtained from University of Calabar Teaching Hospital (UCTH), Cross River State and the Department of Personnel, Research, and Statistics (PRS), Ministry of Education, Akwa Ibom State.

The sample size was determined using the Taro Yamane’s method (Yamane, 1967). Facial width was measured as the distance between the posterior ramus of one zygomatic arch to the other as shown in Figure 1(A) , facial length was measured as the distance between the nasion and the menton (submentum) as depicted in Figure 1(B) while the facial and ear parameters were measured with the aid of a spreading caliper as depicted in Figure 1(C) . Ear length was measured as the distance between the superaurale and subaurale (i.e. between superior most border of helix and the inferior most border of lobule) as illustrated in Figure 2(A) , Figure 2(B) .

Ear width was measured as the distance between the protragion and the postaurale (i.e. between the base of tragus and the border posterior to the scapha) as illustrated in Figure 2(C), Figure 2(D).

All measurements were carried out by the researcher to avoid inter-observer variability. The subjects were age group between (2 - 10 yrs). Measurements were carried out when subjects were relaxed, breathing quietly, and sitting upright with the head supported, the investigator adjusted the lips of the spreading caliper using the adjustment knob on the caliper to reach the desired points of measurement on the subject. The measurements taken were recorded.

The facial indices and ear indices were calculated using the equations below [12] .

$FacialIndex=\frac{FacialLength}{FacialWidth}\times 100$

$AuricularIndex=\frac{AuricularWidth}{AuricularLength}\times 100$

The data was statistically analyzed using SPSS software and the results were compared among the two ethnic groups. Students-t-test was used for comparison between means and the statistical significance was set at p < 0.05.

The present study investigated and compared the ear and facial indices of Efik and Ibibio female children (2 - 10 years) in selected local government areas of Cross River and Akwa Ibom States of Nigeria. The result revealed hypereuriproscopic face (very broad face) as the prevalent face type among female children of both ethnic groups based on the mean proscopic index.

When the facial index of same sex at age groups (2 - 10 yrs) was compared between females of the two ethnic groups, it was observed that the prevalent face type for each of the three age groups between the two ethnic groups was hypereuryproscopic face (very broad face).

Facial dimensions and indices tend to increase as the age increases in both ethnic groups, indicating increasing variations with age. This may be due to the fact that body dimensions increase physiologically as one grows up, this agrees with the documented literature that the facial indices increase as the age advances [12] . When the facial index was compared between females of the two ethnic groups, it was observed that the prevalent face type between the two ethnic groups was hypereuryproscopic face (very broad face). However, the values for Efik females were significantly different from Ibibio females (p < 0.05), suggesting some levels of ethnic variation. This can be attributed to their history and cultural differences as they are two different ethnic groups with a different root [13] . Data obtained have shown the ear index to be almost similar in value among females of both ethnic groups, suggesting the absence of ethnic variation. This may be attributed to environmental factors even though an author reported that when considering the ear for identification, the structures of the external ear in two individuals are always synonymous hence, hard to distinguish [8] .

The results also revealed that while the other dimensions of the ear tend to increase slightly with age, the mean ear (auricular) indices were found to decrease with advancing age for Ibibio ethnic group and Efik females. The decrease in auricular indices suggests an increase in length of the ear with age, which in turn suggests a growth in the lobule of the ear. The decrease in indices may be as a result of environmental factors such as climate and nutritional intake [14] . Purkait & Singh [15] reported in their work that the mean auricular indices decrease with increasing age. When the auricular (ear) index of females were compared between the two ethnic groups, it was observed that the auricular indices of Efik females was not significantly different from Ibibio females (p < 0.05), indicating the absence of ethnic variation. This may be attributed to environmental factors such as dietary patterns [14] .

The present study demonstrated significant differences between the two ethnic groups in terms of ear and facial dimensions and indices indicating ethnic variation.

The results showed hypereuryproscopic face as the prevalent face type among females of both ethnic groups. This result can be of importance in sex, ethnic, and racial differentiation, and in clinical practice, aesthetics and forensic medicine. This study should be carried out on males of both ethnic groups.