ORIGINAL  
Niger J Paed 2012; 39 (4):189 –193  
Oyinlade OA  
Olowu AO  
Relationship between age and  
location of the apex beat among  
apparently healthy Nigerian  
children  
Ogunlesi TA  
DOI:http://dx.doi.org/10.4314/njp.v39i4,8  
Accepted: 11th May 2012  
Abstract Background: Normal lo-  
cation of apex beat varies with age  
in children. Location of apex beat is  
an integral part of routine cardiovas-  
cular system examination in clinical  
practice. However, there is paucity  
of literature on apex beat location in  
Nigerian children.  
Objective: The aim of this study was  
to locate apex beat position in ap-  
parently healthy Nigerian children  
from birth to ten years, and to relate  
the location with age.  
Subjects and Methods: This was a  
cross sectional study carried out in  
Sagamu, Nigeria. A sample size of  
two hundred and thirty-seven was  
calculated from a previous study.  
Hence two hundred and thirty-seven  
apparently healthy Nigerian children  
who satisfied the inclusion criteria  
were enrolled for the study. Apex  
beat location in the intercostal space  
was determined and distance of  
apex beat from the midline, mid-  
clavicular line and nipple lines were  
measured. The measured distances  
were related to age using linear  
regression and Pearson correlation.  
Results: The mean distance of apex  
beat from the midline from birth to  
10 years ranged from 2.3cm to  
6.4cm. The distance of apex beat  
from the midline increased progres-  
sively with age. In children up to  
the age of three years, the apex beat  
Oyinlade OA  
(
)
Department of Paediatrics Federal  
Medical Centre, Ido-Ekiti Nigeria.  
Email: ladealex2005@yahoo.com  
Olowu AO, Ogunlesi TA  
Department of Paediatrics, Olabisi  
Onabanjo University Teaching  
Hospital, Sagamu Nigeria  
th  
was in the 4 left intercostals space.  
In 91.7%, 51.3% and 14.3% of chil-  
dren aged four, five and six years  
respectively, the apex beat was pre-  
th  
sent in the 4 left intercostal space.  
Above six years, it was located in  
th  
the 5 left intercostals space.  
Conclusion: The location of the  
apex beat from the midline was  
strongly related with age Thus, the  
distance of apex beat from the mid-  
line can be predicted from age in  
months.  
Keywords: Apex beat, Children,  
Mid-clavicular line, Nigeria, Nipple  
line  
Introduction  
nation. Therefore, the knowledge of the normal apex  
beat positions in childhood will facilitate early detection  
of abnormal cardiac size which could be a pointer to an  
underlying cardiac disease. This will aid early referral of  
children in these categories for proper evaluation, espe-  
cially from rural settings where most of these children  
are born. Thus, it is important to ascertain the relation-  
ship between age and another essential clinical landmark  
like the location of the apex beat. Therefore, the objec-  
tive of this study is to measure apex beat location from  
anatomical landmarks on the anterior chest wall and  
relate it to age.  
The apex beat is the lowerm-o5 st and outermost point of  
1
maximal cardiac pulsation. Generally, normal apex  
beat location in children has been described to be in the  
fourth left intercostal space about mid-clavicular line  
from birth to two years and in the fifth left intercostals6  
space, about mid-clavicular line after two years of age.  
7
The study by Antia et al , about three decades ago de-  
scribed normal apex beat position in childhood in some  
Jamaican children. That study found apex beat to be  
better described with distance of apical impulse from the  
midline than with the mid-cla7vicular line which hitherto  
had been the reference point.  
It is notable that cardiac diseases are associated with  
changes in the normal position of the he8a-1r0t (displaced  
Methods  
apex beat), usually due to cardiomegally,  
which can  
This was a cross sectional study carried out on appar-  
ently healthy Nigerian children between December 2009  
easily be detected during routine bedside clinical exami-  
1
90  
and April 2010. The study was conducted in Sagamu,  
Ogun State; a town located within the Yoruba cultural  
region of the southwestern Nigeria. Institutional ethical  
approval was obtained from the Scientific and Ethical  
Review Committee of the Olabisi Onabanjo University  
Teaching Hospital, Sagamu and informed consent was  
also obtained from the parents and guardians of selected  
children.  
apex beat2was determined according to standard clinical  
1
methods. The apex beat was determined in the supine  
position in the newborn babies and infants, in erect posi-  
tion in children aged between one and three years, and in  
7
both erect and supine positions in the others. The loca-  
tion of the apex beat was measured from the midline,  
nipple line and the mid-clavicular line. The midline was  
established by joining the central point in the supraster-  
nal fossa to the xiphisternal angle, and the horizontal  
distance of the apex beat and the nipple were measured  
from the midline using an inelastic tape. The extreme  
medial and lateral ends of the clavicle were identified  
and the corresponding points on the skin marked with  
ink. The length of the clavicle represented by these  
points marked on the skin was similarly measured. Half  
of the clavicular length was taken as corresponding to  
the mid clavicular line. Horizontal distance of the mid  
clavicular line was measured from the midline. During  
measurements in the erect and supine positions, the up-  
per arms were lightly pressed against the chest wall so  
as not to stretch the skin. The trachea position was also  
checked with the index and ring fingers on each of the  
manubrioclavicular joint and the middle finger locating  
the trachea via the suprasternal notch. Any deviation  
automatically disqualified the child from participating in  
the study.  
The inclusion criterion was age from birth to 10 years.  
The newborn babies included were term, products of  
spontaneous vaginal delivery, appropriate for gestational  
age from 12 hours of age (when events of delivery had  
resolved), without asphyxia or other forms of critical  
illness. Subjects with history suggestive of acute or  
chronic ill health such as congenital heart disease or  
other cardiovascular diseases, sickle cell anaemia,  
chronic respiratory tract disease or chronic renal disease  
were excluded from the study. Subjects with cardiac  
murmurs, chest deformities or displaced trachea were  
also excluded.  
7
Sample size: A previous study reported the mean apex  
beat distances from the midline in different age groups  
of children from birth to ten years. Assuming a margin  
of error of 5% of the mean for each age group, the sam-  
ple that would be necessary to study at 5% level of sig-  
nificance (95% confidence inte2rval) was calculated from  
The data were analysed with SPSS version 15.0 soft-  
ware using the Students test, linear regression analysis  
and the Pearson Correlation (r). P values less than 0.05  
were accepted as significant.  
11  
2
2
the formula: N = (ꢀ [ Zꢁ/2] ) / ε where ꢀ is the as-  
sumed standard deviation, Zα/2 represents Type -1 Error  
while ε is the margin of error (5% for each age group).  
The total calculated sample size was 237. Table 1 shows  
the calculated sample size for each age group.  
Sampling method: The neonates in this study were re-  
cruited from term normal delivery cases from Olabisi  
Onabanjo University Teaching Hospital, Sagamu while  
infants were recruited from immunization and Child  
Survival Clinics of the same institution. Recruitment  
was done consecutively until the desired sample size for  
each age group was met.  
Results  
A total of 237 children with ages ranging from 12 hours  
to 10 years were studied (Table 1). These consisted of  
131 (55.3%) males and 106 (44.7%) females  
(
M: F = 1: 0.8).  
Recruitment of children aged between one and five  
years was made from daycare and nursery schools in  
Sagamu. There were 106 daycare and nursery schools in  
Sagamu from which five were randomly selected. Chil-  
dren between six to ten years were recruited from pri-  
mary schools. There were 150 primary schools in Sa-  
gamu town out of which five were also randomly se-  
lected. The selected schools were visited and subjects  
were made to queue up for physical examination. Those  
who satisfied the inclusion criteria were recruited con-  
secutively from age-group to age-group until the desired  
sample size for each age group was met.  
Table 2 shows the mean distance of the apex beat from  
the midline in both erect and supine positions. The mean  
distance ranged between 2.3cm (median=2.3cm) in the  
neonates and 6.39cm (median=6.35cm) in children who  
were 10 years old. No significant difference was found  
in comparison of apex beat distance in the supine and  
erect positions.  
Location of apex beat from the midline in relation to  
mid-clavicular line and nipple line  
The location of apex beat in relation to mid-clavicular  
line, nipple line and midline is presented in Table 3. The  
mean distance of apex beat measured from the midline  
progressively increased with age till age nine years. The  
mean distance of the apex beat from the midline was  
consistently less than the distance of the mid-clavicular  
line and nipple line from the midline up to age seven  
years while in children older than seven years, the mean  
Measurements: Before the commencement of the  
study, two research assistants who were junior resident  
doctors in the same department with the researcher were  
trained in the art of physical examination and apex beat  
location and for every ten children the researcher exam-  
ined, the research assistants examined one child to mini-  
mize observer error. For each subject, the location of the  
1
91  
Table1: Sample size calculation for each age group  
using meandistance of apex beat from the midline in a  
previous study  
Table 2: Comparison of mean distance of apex beat  
from the midline in the supine and erect positions  
N
Supine  
Erect  
t-test  
Age(months)  
Mean  
ꢀ
Z
ꢁ/2  
ꢂ
Sample size  
Age(months)  
Mean (SD)  
Mean (SD) p-value  
NEONATES  
2
.8  
.8  
0.4  
1.96  
1.96  
0.19  
0.14  
17  
31  
Neonates  
2-12  
17  
2.3 (0.6)  
2.7( 0.4)  
ND  
ND  
NC  
NC  
NC  
NC  
0.9  
0.9  
1.0  
0.9  
0.9  
0.9  
0.9  
2
-12  
3
0.4  
31  
ND  
1
2
3
3-24  
5-36  
7-48  
4.1  
4.7  
4.6  
0.7  
0.3  
0.4  
1.96  
1.96  
1.96  
0.21  
0.24  
0.23  
43  
06  
12  
13-24  
43  
06  
12  
39  
3.4(0.6)  
4.8(1.1)  
5.0 (1.3)  
4.9(1.1)  
5.5 (0.8)  
6.0(0.6)  
6.3 (0.7)  
6.7(0.5)  
6.4 (0.8)  
2
5-36  
37-48  
9-60  
ND  
4
6
9-60  
1-72  
5.0  
5.1  
5.2  
0.8  
0.5  
0.7  
1.96  
1.96  
1.96  
0.25  
0.26  
0.26  
39  
14  
28  
5.0 (1.3)  
4.9 (1.1)  
5.5 (0.7)  
6.0(0.6)  
6.3 (0.6)  
6.7(0.5)  
6.4(0.9)  
7
8
3-84  
5-96  
4
5.4  
0.6  
1.96  
0.27  
19  
9
1
7-108  
5
5
.5  
.7  
0.5  
0.6  
1.96  
1.96  
0.28  
0.29  
12  
16  
61-72  
73-84  
14  
28  
09-120  
TOTAL  
237  
8
9
1
5-96  
19  
distance of the apex beat from the midline was greater  
than the mid-clavicular line and nipple line from the  
midline. The apex beat was consistently medial in loca-  
tion in relation to the mid-clavicular line and the nipple  
line till seven years of age. Thereafter, it was located  
lateral to the mid-clavicular and nipple lines.  
7-108  
09-120  
12  
16  
NC - Not computed; ND – Not done  
Table 3: Location of apex beat from the midline in relation to mid-clavicular line and nipple line from the midline  
Age(months)  
Mean apex beat  
from Midline(cm) line (cm)  
Mid-clavicular Nipple line (cm) Location of apex in  
relation to MCL  
Location of apex  
in relation to NL  
Neonates  
2.3 ± 0.6  
2.7 ± 0.4  
3.4 ± 0.6  
4.8 ± 1.1  
5.0 ± 1.3  
5.0 ± 1.1  
5.5 ± 0.8  
6.0 ± 0.6  
6.3 ± 0.7  
6.7 ± 0.5  
6.4 ± 0.9  
3.5 ± 0.6  
4.0 ± 0.6  
4.5 ± 0.7  
5.6 ± 0.8  
5.1 ± 0.6  
5.6 ± 0.8  
6.1 ± 0.6  
6.2 ± 0.5  
6.0 ± 0.7  
6.0 ± 0.7  
5.9 ± 1.2  
4.1 ± 0.5  
4.5 ± 0.5  
5.2 ± 0.8  
5.2 ± 1.2  
5.4 ± 0.6  
5.8 ± 0.6  
5.8 ± 0.7  
6.4 ± 0.6  
6.2 ± 0.7  
6.7 ± 0.7  
6.0 ± 1.0  
Medial  
Medial  
Medial  
Medial  
Medial  
Medial  
Medial  
Medial  
Medial  
Lateral  
Lateral  
Lateral  
2
1
2
3
4
6
7
8
9
1
-12  
Medial  
3-24  
5-36  
7-48  
9-60  
1-72  
3-84  
5-96  
7-108  
09-120  
Medial  
Medial  
Medial  
Medial  
Medial  
Medial  
Lateral  
Lateral  
Lateral  
Relationship between distance of apex beat measured  
from the midline and age  
Using the above stated equation, the distance of apex  
beat from the midline was predicted for all the age  
groups as shown in Table 4. This table also shows a  
comparison between the actual mean distance of apex  
beat from the midline and predicted mean distance of the  
apex beat from the midline. There was no significant  
difference between actual mean distance of apex beat  
from the midline and the predicted mean distance of  
apex beat from the midline in all the age groups except  
in infancy and in the 9 to 10 years age- group.  
The distance of apex beat from the midline strongly and  
positively correlated with age (r = 0.869; p = 0.000).  
The relationship between age (in months) and distance  
of apex beat from the midline was described with a lin-  
ear regression equation as follows:  
Distance of apex beat from midline = 2.741 + (0.035 x  
age in months) where 2.741 and 0.035 were constant  
values generated from the linear regression analysis.  
1
92  
Table 4: Comparison between mean apex beat from the  
midline and predicted apex beat from the midline  
years, the apex beat was in the left 4th intercostal space  
in 91.7% of the subjects and in the 5th left intercostal  
space in 8.3% of the subjects. In those between four and  
five years, the apex beat was in the 4th left intercostal  
space in 51.3% of the subjects and in the 5th left inter-  
costal space in 48.7%. Thereafter, with increasing age,  
the apex beat gradually moved into the 5th left intercos-  
tal space so that above six years of age, the apex beat  
was consistently located in the 5th left intercostal space  
in all the children studied.  
Age Group  
Mean apex  
beat from  
Midline (cm)  
Predicted Apex  
beat ( x = k +by)  
(cm)  
P- values  
Neonates  
2.3 ± 0.6  
2.7 ± 0.4  
3.4 ± 0.6  
4.8 ± 1.1  
5.0 ± 1.3  
5.0 ± 1.1  
5.5 ± 0.8  
6.0 ± 0.6  
6.3 ± 0.7  
6.7 ± 0.5  
6.4 ± 0.9  
2.8  
3.2  
3.4  
3.7  
4.6  
5.1  
5.5  
6.0  
6.4  
6.9  
7.4  
0.02∗  
0.00∗  
0.575  
0.052  
0.268  
0.282  
0.868  
0.926  
0.310  
0.155  
0.000∗  
2
1
2
3
4
6
7
8
9
1
-12  
3-24  
5-36  
7-48  
9-60  
1-72  
3-84  
5-96  
7-108  
09-120  
Table 5: Proportion of children with apex beat location in  
specific Intercostal spaces in the erect or supine Position  
Age (months) Total No  
Athpex beat in  
Apex beat in  
Intercostal 5 Intercostal  
th  
4
Space  
Space  
Neonates  
17  
31  
17 (100.0)  
0 (0.0)  
2
-12  
31 (100.0)  
0 (0.0)  
1
2
3
3-24  
5-36  
7-48  
43  
6
43 (100.0)  
6 (100.0)  
11 (91.7)  
0 (0.0)  
0 (0.0)  
1 (8.3)  
12  
∗
Statistically significant differences  
4
9-60  
39  
20 (51.3)  
19 (48.7)  
Relationship between age and the apex beat location in  
the intercostals spaces  
6
7
8
1-72  
3-84  
5-96  
14  
28  
19  
2 (14.3)  
0 (0.0)  
0 (0.0)  
12 (85.7)  
28 (100.0)  
19 (100.0)  
Table 5 shows the comparison of proportions of children  
in the different age groups with apex beat in specific  
intercostal spaces in the erect or supine position. The  
apex beat was in the left 4th intercostal space in all sub-  
jects from birth to three years. Between three and four  
97-108  
1109-120  
12  
16  
0 (0.0)  
0 (0.0)  
12 (100.0)  
16 (100.0)  
Figures in parentheses are percentages  
th  
three years, the apex beat was in the 4 left intercostal  
space whereas in children aged four, five and six years,  
th  
the apex beat was in the 4 left intercostal space in some  
proportions while in the 5 left intercostal space in oth-  
th  
Discussion  
ers. This was similarly reported in the Jamaican study.  
However, in this study, all childrteh n above six years had  
their apex beat located in the 5 left intercostal space  
whereas in the Jamaican study, some proportions of  
children above six years had their apex beat located in  
1
3
Earlier report had shown that the apex beat location in  
childhood varies with age as well as with various  
physiological factors which cause a shift of the apical  
portion of the left ventricle towards the chest wall. Since  
the th4 ickness of the left ventriclar wall increases with  
th  
the 4 left intercostal space.  
1
age, the position of the apex beat in childhood in rela-  
tion to mid-clavicular line, nipple line and intercostal  
space would be expected to change with age as well as  
the chest circumference.  
With respect to the distance of apex beat f7rom the mid-  
line in relation to age, the Jamaican study reported that  
from the first birthday onwards, using linear regression  
equation, the apex beat is about 3.8 plus 0.2cm for every  
year of age while this study showed that the apex beat is  
about 2.7 plus 0.04cm for every month of age. These  
two linear regression equations are both useful, the for-  
mer was computed in years of age while the latter was  
computed in months of age, to accommodate neonates  
and infants. The lack of statistically significant differ-  
ences between actual mean of apex beat from the mid-  
line and predicted mean for most of the age groups  
With respect to the position of the apex beat in the inter-  
costal spaces, this study did not support stohme of the  
earlier reports that the apex beat is in the 4 left inter-  
costal space in all children from birth to the age of t6wo  
th  
years and thereafter in the 5 left intercostal space, or  
th  
that 1it5-i1s6 in the 4 left intercostal space in children of althl  
ages  
left intercostal space.  
or that irrespective of age, it is usually in the 5  
17  
(
using this latter linear regression equation) implies the  
The findings in the present study agrees with an earlier  
report in a similar study of position of apex beat in  
childhood done in Jamaica over three decades ago. The  
usefulness of this linear regression equation in predict-  
ing apex beat distance from the midline in the age group  
studied. The significant differences noticed in infancy  
and nine to ten years age-group may be due to the small  
7
present study showed that in all children up to the age of  
1
93  
sample size studied in those age groups.  
restless and uncooperative in the supine position thereby  
making accurate measurements difficult. Another limita-  
tion was the unavailability of echocardiograms to ex-  
clude structural cardiac diseases and cardio version.  
With regard to the relationship between apex beat dis-  
tance from the midline, nipple line and mid-clavicular  
7
line, earlier report stated that these landmarks were not  
accurate indices of normal apex beat location and that  
while the mid-clavicular was a relatively better reference  
point compared with the nipple line, the nipple line was  
of no value in assessing normal cardiac position and  
Conclusion  
7
should not be used in clinical practice. Furthermore, it  
The findings in the present study have established local  
peculiarities in the location of apex beat in relation to  
age. The mean distance of apex beat from the midline  
from birth to nine years progressively increased with  
age. A multicentre study on apex beat location in normal  
children is highly desirable to validate the findings in  
this present study.  
was reported that the position of the nipple line in rela-  
tion to the apex beat was well outside the apex beat in  
children of all ages, the mean distance of the nipple line  
being consistently greater than that of the apex beat.  
However, in this study, findings showed that the apex  
beat was consistently medial to the mid-clavicular line  
and nipple line up to the age of seven years after which  
the apex beat was lateral to mid-clavicular line and nip-  
ple line.  
Conflict of interest: None  
Funding: None  
A limitation of the study was the inability to measure all  
the parameters in the same phase of respiration in all the  
subjects hence it was difficult to harmonize mid-  
clavicular line, nipple line and apex beat measurements  
with respiratory cycle. However, this, does not seem to  
have altered the measurements significantly. Measure-  
ments were done only in erect position for subjects aged  
one to three years because these subjects were rather  
Acknowledgement  
The efforts of Drs Adekoya O.A and Ayeni V.A of  
Department of Paediatrics, Olabisi Onabanjo University  
Teaching .Hospital Sagamu are well appreciated.  
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