Let's learn the anatomical basis behind thoracoabdominal respiration in females and abdominothoracic respiration in males

1. Anatomy
behind
Thoracoabdominal respiration (Female)
Vs
Abdominothoracic respiration (Male)

2. Anatomical differences between
male & female respiration
Female Male
Rib cage inclination Greater rib cage
inclination
More horizontally
oriented
Rib cage dimensions
(Anterior-posterior diameter,
lateral diameter)
Lesser Greater
Diaphragm length Shorter
(by ~ 9% than male)
Longer
Breathing type Thoracoabdominal
(chiefly by ribs)
Abdominothoracic
(chiefly by diaphragm)

3. Thoracoabdominal respiration in female
1. Females have greater inclination of rib cage than male
 More inclined ribs make intercostal (inspiratory) muscles
raise ribs more effectively. So, increased action of intercostal
muscles account for more pronounced thoracic breathing.
Frontal view Lateral view
* Blue (Male), Red (Female)

4. • But why do females have more inclined rib cage ?
 Unlike male, whose rib cage play a role to accommodate
lung volume displacement only, female rib cage serve
dual role to accommodate both lung volume &
abdominal volume displacement. So, females have large
volume capacity of rib cage compared to their lung size.
• Why is abdominal displacement so important in female ?
 It’s due to pregnancy in female. The more inclined rib
cage in female is a functional adaptation to pregnancy to
accommodate abdominal distension by pregnancy.
 This minimizes the distending effect of pregnant uterus
on lung & also decreases abdominal pressure.

5. Thoracoabdominal respiration in female
2. Females have shorter rib cage dimensions
 Females have smaller anterior-posterior diameter &
lateral diameter of rib cage than males.
 It’s mostly accounted by greater inclination of rib cage.
Male Female
3. Females have shorter diaphragm length than males
 Diaphragm is ~ 9 % shorter in females than male.

6. Abdominothoracic respiration in male
• Respiration in male is chiefly by diaphragm.
 Male have more horizontally oriented rib cage. So, there
is inefficient action of intercostal muscles, making
thoracic breathing less pronounced in male.
 Males have longer diaphragm
(~9 % greater than females)
• Diaphragmatic breathing could be a compensation for
inefficient action of intercostal muscles in male.
• Greater diaphragmatic action in male is linked to
 Male thoracic morphology (wider at caudal part)
 Greater mediolateral expansion of lower lungs
 More pyramidal shape of male lung.

7. Reference
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC59
80468/