|Year : 2020 | Volume
| Issue : 1 | Page : 27-31
Morphometric analysis and key dimensions of the female breast: a baseline study of 500 nulliparous Nigerian females
Egiehiokhin Isiwele1, Richard E. E. Nnabuko2, Iheuko S Ogbonnaya2
1 Plastic and Reconstructive Surgery Division, Department of Surgery, University of Calabar Teaching Hospital, Calabar, Nigeria
2 Department of Plastic and Reconstructive Surgery, National Orthopaedic Hospital, Enugu, Nigeria
|Date of Submission||06-Apr-2020|
|Date of Acceptance||11-Aug-2020|
|Date of Web Publication||17-Sep-2020|
Plastic and Reconstructive Surgery Division, Department of Surgery, University of Calabar Teaching Hospital, Calabar
Source of Support: None, Conflict of Interest: None
Context: The female breast is a symbol of femininity. With recent developments in the surgical management of breast pathology, women now demand better aesthetic outcomes. Data on breast morphometry which should guide Nigerian breast surgeons in decision making is scarce. Aims: This study was aimed at measuring morphometric breast values in nulliparous Nigerian females, thus establishing reference data for the region. Settings and Design: This was a prospective and community-based study in which volunteer female students from the study hospital and 3 secondary schools in the community underwent breast measurements in order to establish reference data. Methods and Material: Physical measurements were carried out using measuring tape and meter rule, in the standing position. Statistical Analysis Used: Data obtained were analyzed using Statistical Package for Social Sciences (SPSS) version 16 and Student’s t-test analysis carried out.Results : Five hundred female volunteers with age range 15–30 years were studied. The average distance from the suprasternal notch to the right and left nipples were 19.76 cm and 20.09 cm respectively. The average distance from right and left nipples respectively to their inframammary folds were 8.13 cm and 8.28 cm. Breast dimensions were symmetrical in >50% of subjects. In the subjects with asymmetry, more were found to have greater left breast dimensions than right. Conclusions: Physical measurements of the Nigerian female breast are comparable with ranges in other parts of the world except for the Inframammary fold to nipple distance which is longer than values in studies on white subjects. This study establishes preliminary morphometric breast reference data for Nigerian females.
Keywords: Female breast, morphometry, physical measurements
|How to cite this article:|
Isiwele E, Nnabuko RE, Ogbonnaya IS. Morphometric analysis and key dimensions of the female breast: a baseline study of 500 nulliparous Nigerian females. Nigerian J Plast Surg 2020;16:27-31
|How to cite this URL:|
Isiwele E, Nnabuko RE, Ogbonnaya IS. Morphometric analysis and key dimensions of the female breast: a baseline study of 500 nulliparous Nigerian females. Nigerian J Plast Surg [serial online] 2020 [cited 2021 Jun 23];16:27-31. Available from: https://www.njps.org/text.asp?2020/16/1/27/295255
| Introduction|| |
The female breast is an object of attraction and a symbol of femininity. It is a very dynamic organ of the human body, continuously changing in size and position during the life of a person. In recent times, there have been several important developments in the surgical management of breast pathology in the sub region and this has received considerable attention and women today are not only demanding effective surgical treatment, but good aesthetic outcomes as well. Thus, like any other field, breast surgery has evolved into both a surgical science and an art. An essential part of aesthetic surgery is an understanding of the aesthetic ideals of the body. Morphometry is the measurement of the form of organisms or their parts. The key morphological properties of the breast that are of interest are breast shape, position and volume. The goal of plastic surgery of the breast is to recreate as close as possible a natural breast. Breast surgeries have been carried out in Nigeria with commendable outcomes, but no local reference data on breast morphometry has been developed. The aim of this study was to measure morphometric breast values in nulliparous Nigerian females and to create a reference data that describes position of key landmarks on the Nigerian female breast for breast aesthetic and reconstructive surgery.
| Subjects and methods|| |
This was a community-based study aimed at analyzing morphometric details of the female breast, carried out in Enugu, South Eastern Nigeria in April 2014. It was a prospective and observational study. The study population included volunteer female students from the study hospital’s community as well as from three female secondary schools in the Enugu Metropolis. Ethical clearance was obtained from the Institutional Review Board of the National Orthopaedic Hospital, Enugu (IRB Number − S/313/1/848) and permission obtained from the Enugu State Ministry of Education for inclusion of the three secondary schools in the study. Written informed consent was obtained from all subjects recruited for the study. Where the subject was less than 18 years of age, parents or guardians had to give their consent by signing the appropriate section of the consent form, after duly educating the participants about the study. Consecutive volunteers who met the inclusion criteria were recruited until the sample size was complete.
The minimum sample size was estimated using the Leslie Kish formula for single proportion:
N = z2pq/d2.
Where n = desired sample size. (When population is greater than 10,000),
z= Standard normal deviation being 1.96 at 95% confidence level,
p = the population (target population was estimated to have a particular characteristic of 50%). This is used when there is no reasonable estimate.
q = 1−p = 0.5
d = the difference between the true population rate and the sample (precision) set at 5% = 0.05.
Substituting in the formula:
n = 1.962 × 0.5 × 0.5
n = 384.16 ∼ 400 (to the nearest hundred).
Being that this work was carried out to establish a baseline, a sample size of five hundred (500) was finally chosen.
Subjects within the age range of 15–30 years were studied based on the fact that this is the age at which the breasts are fully developed as shown by the work done in this sub-region by Fakeye and Fagbule and the age at which most females are nulliparous. All females within the age range who were nulliparous, with no history of breast disease or surgery were included.
Pregnant females (using the last menstrual period history and clinical feature of linea nigra on the abdomen), females using hormones in any form, those with congenital abnormality of the chest and/or breast(s), previous injuries/ burns to the breast, those with clinically detectable breast diseases and those who were unable to stand erect for examination were excluded.
| Materials and methods|| |
Physical measurement of the breast was chosen as the morphometric method in this study because of its reproducibility and simplicity. A proforma was used to record details of volunteers’ personal and clinical data as well as findings from relevant measurements. All measurements on the breasts were taken by the investigators with a measuring tape and a meter rule. Measurements were done on the subjects in the standing position with their heads in the anatomic position and upper limbs by their sides. Privacy for volunteers was given due consideration. Measurements carried out on the breasts (in centimeters) were:
Suprasternal notch to nipple distance (SNN): This was done using a meter rule and measurements were taken from the mid notch to the mid nipple diameter on either side. Nipple to nipple distance (NN) − using a meter rule, measurements were taken at the mid nipple diameter on both sides. Midclavicular line to nipple distance (MCLN) − using a meter rule, measurements were taken from the mid clavicle to the mid nipple. Inframammary fold to nipple distance (NIMF) − using a measuring tape, measurements were taken from the base of the breast to the base of the nipple. Areolar diameter (AD) − a meter rule was placed transversely on the areola to measure from one end to the other. Nipple diameter (ND) − a meter rule was used to measure the width of the nipple. Breast diameter (BD) − the widest part of breast, taken with a measuring tape circumferentially around the thorax at the level of the nipple and the figure rounded off to the nearest even number. Chest diameter (CD) − This was taken firmly with a measuring tape circumferentially around the thorax at the level of the inframammary fold. Measurement was rounded off to the nearest even number.
Chest and breast circumference (To determine bra cup size and indirectly breast volume): The difference between BD and CD was calculated and if it was 2.54cm, the breast cup size is A, if 5.08cm the breast cup size is B, if 8.62cm the cup size is C, if 11.16cm the cup size is D. (Key parameters in breast measurements are shown in [Figure 1])
|Figure 1 Key parameters in breast measurement in an 18 year old female volunteer. IMF, inframammary fold; LN, Left nipple; MCL, mid-clavicular line; RN, right nipple; SN, suprasternal notch|
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Data obtained from the proforma were entered into a spreadsheet and analyzed using Statistical Package for Social Sciences (SPSS), version 16 and Microsoft Excel. Data were summarized as frequencies, percentages, means, and standard deviations and presented in tables. Tests of correlation (Student t-test) at 95% confidence limit and P-value of 0.05 were carried out.
| Results|| |
Five hundred female volunteers who met the inclusion criteria were recruited, with the mean age in this study being 18 ± 3years and the range 15–30 years. Eighty percent of subjects were from Enugu state of Nigeria. All subjects were single, urban dwellers. Sixty percent of them were secondary school students, 30% were nursing students and 10% plaster technician students. Values of physical breast measurements obtained and statistical analysis are shown in [Table 1],[Table 2],[Table 3],[Table 4] while key parameters in breast measurement are shown in [Figure 1].
|Table 3 Student t-tests analysis of the comparison of right and left breast measurements|
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| Discussion|| |
The five hundred (500) subjects studied were all unmarried and 90.40% of them were from South-East, Nigeria, with Enugu state representing 80.00% of the population. The results from this study therefore represent findings majorly from the South-Eastern part of the country. All volunteers were students and urban dwellers who had worn a brassiere right from when their breasts were big enough to enter a size. The mean age recorded was 18 years and this is in keeping with findings in a similar study done by Agbenorku et al. in Ghana in 2000 on 438 young females within the age range of 16–22 years and with a mean age of 17 years. The age is vital when carrying out morphometric breast analysis because the breast is a very dynamic organ of the human body, continuously changing in size and position during the life of a person. Like the study in Ghana, ours studied nulliparous breasts, bearing in mind that every woman coming for a breast aesthetic procedure would expect her breast to be more youthful looking and not sagging. Vandeput and Nelissen in 2002 carried out a morphometric analysis of 973 women’s breast in Belgium, but did not put into consideration the different breast changes associated with the aging female, as his study population were aged between 18 and 60 years. This study had to exclude women who had undergone breast changes as a result of ageing, breastfeeding and pregnancy.
The mean value of all the breast parameters measured in this study were similar to those recorded in previous studies carried out in different parts of the world,,,,, except for the NIMF measurement which was longer in this study (8.21cm) compared to the values measured by Smith et al. − 6.64cm and Vandeput − 6.94 cm. The study by Penn in South Africa recorded a value of 6.74cm but it is not clear if the population was predominantly white. The NIMF parameter was 9 cm in the study done in Ghana. This study, like ours was carried out in native black Africans, and thus may indicate that the NIMF in black Africans is much longer compared to that of the whites. Despite the fact that the study by Vandeput did not exclude subjects with non-nulliparous breasts and also that the age range was up to 60 years, the NIMF was still less than what was measured in our study. Furthermore, comparing the Ghana study with ours, a lower value would have been expected in the Ghana study because the age groups studied were younger than the age groups in our study and it is expected that NIMF measurement increases with age, however this was not the case., All these indicate a geographical variation in the positioning of the breast, as NIMF is an important landmark for breast reconstruction in aesthetic surgery.
The mean breast cup size in our study was 11.28cm, which is equivalent to cup size “D” and the mean chest diameter was approximately 74 cm (which is equivalent to breast band size 32). McGhee and Steele in their study in Australia on 104 women found the cup size to be “DD”. Their study however did not consider the effect of age in the sample selection. Cup size is helpful in planning for aesthetic and reconstructive breast surgery as well as in the clothing and textile industry in the designing of brassiere and clothing for women in the sub-region.
The measurements of breast dimensions were found to be symmetrical in more than 50% of the subjects in all the variables measured. In the subjects that had asymmetry, more were found to have left breast dimensions greater than right breast dimensions. The variables measured were the nipple to inframammary fold distance, suprasternal notch to nipple distance, midclavicular line to nipple distance, areolar diameter and nipple diameter. Similar finding of larger left breast sizes was recorded by Agbenorku in Ghana. Scutt et al. in their work considering the relationship of breast asymmetry with breast cancer also noted the left breasts to have slightly larger volumes than the right. It has been suggested by anecdotes that the left breast responds more to surging estrogen levels, explaining the reason for the increase in left breast volume. However, the right breast has also been found by some researchers to be significantly greater in volume than the left breast. This was recorded by Avsar in his study on 385 Turkish female undergraduates. Breast asymmetry is a difference of form, position or volume of the breast in the same individual., Perfect symmetry may be disturbed by a number of intrinsic and extrinsic factors, including the secretion of hormones such as estrogen. The small random deviations from perfect symmetry that result from such factors are termed fluctuating asymmetry. Fluctuating asymmetry refers to a pattern of bilateral variation where variations on the right and left sides are both random and independent.Pathological causes of asymmetry like breast masses, chest wall deformities and congenital deformities of the breast like Poland’s syndrome were all excluded from this study. Breast asymmetry has been noted during the menstrual cycle and the breast has been observed to be symmetrical during ovulation., Manning et al. in their study in 1996 discussed cyclical asymmetry as temporary within-individual changes in breast symmetry related to the menstrual cycle. They noted it to vary across the menstrual cycle in women, being highest at the beginning and end of the cycle (when women are generally infertile) and lowest in mid-cycle/ ovulation (when fertility is highest). Our study did not look at the effects of menstrual cycle on breast morphometry because most of the subjects did not keep records of their last menstrual period (LMP). This brings to the fore the need for education of the girl-child in our environment on keeping of records of their menstrual cycle and indeed all their health records through enlightenment campaigns as these records are vital.
A limitation of this study was the inability to use more standardized methods like thermoplastic casting or biostereometrics to estimate breast volume because of lack of necessary equipment and this necessitated the use of bra cup size (a less standardized method).
In conclusion, the results of this study have shown physical measurements of the Nigerian female breast to be comparable with ranges in other studies in other parts of the world. The Inframammary fold to nipple distance (NIMF), an important parameter in breast reconstructive surgery, was however found to be longer than values in studies carried out on predominantly white subjects. More than half of the Nigerian females in our study were found to have symmetrical breasts and where asymmetry exists, the left breasts were generally found to be larger than the right. This study thus provides morphometric breast reference data for Nigerian females, which is useful for cosmetic and reconstructive breast surgery decisions.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]