Anatomical differences between
Adults and Children
There are many differences between children, adolescents and adults – physiological, anatomical, cognitive, social and emotional – which all impact on the way illness and disease present in children and young people, as well as the way healthcare is provided.
Unique Vulnerabilities of Children
Children are developmentally, anatomically, and physiologically different from adults. As such, children have unique needs in disaster or emergency situations. For example:
- Children are more susceptible than adults to certain injuries and environmental insults.
- Children with acute injuries or illnesses are more likely than adults to respond to rapid and efficient medical care.
- Since children are not merely “small adults,” they require paediatric-specific equipment and pharmaceuticals.
Key Anatomical Issues
Children’s anatomy differs from adults’ anatomy in four key areas:
- Airway
- Breathing
- Circulation
- Trauma
Key Issues Concerning the Airway
A child’s airway differs in a number of ways from that of an adult.
Child and Adult Airway Diameters
The diameter of a child’s airway is smaller than the airway of an adult. It is important to be aware that the diameter of the airway increases as the child grows.
Given the smaller size of the airway, a child is more likely to experience a compromised airway than an adult is. As the result of injury or the effects of chemical agents, a child with the same degree of airway swelling as an adult will be more seriously affected and may become symptomatic earlier.
Clearing the airway is the priority with all casualties, but special attention to children is warranted, given their risk of becoming symptomatic more rapidly and acutely than adults with comparable exposure.
Source: Markenson, D.S. Pediatric Prehospital Care, New Jersey: Prentice-Hall, 2002, p. 97.
Key Issues Concerning the Airway
Differences in the Child and Adult Airway
Source: Markenson, D.S. Paediatric Prehospital Care, New Jersey: Prentice-Hall, 2002, p. 11
Key Issues Concerning Breathing
- In general, children’s chests are relatively healthy and transmit sound and air well. As a result, their chests are hyper resonant, which can make auscultation confusing and may make it difficult to differentiate focal findings from global findings.
- Children’s intercostal muscles are not fully developed, resulting in minimal compensation. As a result, children can go from early distress to failure in a short period of time. In addition, children use other muscles, such as the pectorals, in a tripod position to compensate.
Key Issues Concerning Circulation
- Children’s blood volume is much lower than that of adults, meaning that even a small amount of blood loss may be extremely significant for a child. The blood-loss measurements used to assess the level of damage in adults are not applicable to children. When examining a child, assess the amount of blood on the body and on the clothing, and bear in mind that even a small amount of blood loss can be significant in a small child.
- In general, children’s vessel walls are healthy and vasoconstrict exceptionally well. This means that, despite significant blood loss, children can maintain their blood pressure, making blood pressure a poor sign of shock. With children, one should use other symptoms to diagnose shock and should recognise that only in late shock will a child’s blood pressure fall.
Total Blood Volumes
- One-year-old child—10 kg: Blood volume 800 mL; a little more than two cans of drink.
- Six-year-old child—20 kg: Blood volume 1,600 mL; 4.5 cans of drink.
Acceptable ranges for physiological variables
| Age | Approximate Weight (kg) | Systolic BP (mmHg) | Heart Rate (Beats/minute) | Respiratory Rate (Breaths/minute) |
| Term |
3.5 |
60-95 |
120-185 |
25-60 |
| 3 months |
6 |
60-105 |
115-180 |
25-60 |
| 6 months |
8 |
75-105 |
110-180 |
20-55 |
| 1 year |
10 |
70-105 |
105-180 |
20-45 |
| 2 years |
12 |
70-105 |
95-175 |
20-40 |
| 4 years |
15 |
75-110 |
80-150 |
17-30 |
| 6 years |
20 |
80-115 |
75-140 |
16-30 |
| 8 years |
25 |
80-115 |
70-130 |
16-30 |
| 10 years |
30 |
85-120 |
60-130 |
15-25 |
| 12 years |
40 |
90-120 |
65-120 |
15-25 |
| 14 years |
50 |
90-125 |
60-115 |
14-25 |
| 16 years |
60 |
90-130 |
60-115 |
14-25 |
| 17+ years |
65 |
90- 135 |
60-115 |
14-25 |
